neighboring waters that are outside of the riparian area and/or
floodplain but that have a surface or shallow subsurface hydrologic
connection to (a)(1) through (a)(5) waters). Connectivity of ``other
waters'' to downstream waters that do not meet the definition of
adjacent will vary within a watershed and over time, which is why a
case-specific significant nexus determination for ``other waters''
is necessary under (a)(7). See, e.g., id. at 6-2. The types of
chemical, physical, and biological connections between ``other
waters'' and downstream waters are described below for illustrative
purposes. As described in the preamble above, when the agencies are
conducting a case-specific determination for significant nexus under
(a)(7), they examine the connections between the water (including
any similarly situated waters in the region) and downstream waters
and determine if those connections significantly affect the
chemical, physical, or biological integrity of the downstream water,
using any available site-information and field observations where
available, relevant scientific studies or data, or other relevant
jurisdictional determinations that have been made on similar
resources in the region.
    The hydrologic connectivity of ``other waters'' to downstream
waters occurs on a gradient and can include waters that have
groundwater or occasional surface water connections (through
overland flow) to the tributary network and waters that have no
hydrologic connection to the tributary network. Id. at 5-1. The
connectivity of ``other waters'' to downstream waters will vary
within a watershed as a function of local factors (e.g. position,
topography, and soil characteristics). Id. at 3-41 to 3-43.
Connectivity also varies over time, as the tributary network and
water table expand and contract in response to local climate. Id. at
3-31 to 3-33. Lack of connection does not necessarily translate to
lack of impact; even when lacking connectivity, waters can still
impact chemical, physical, and biological conditions downstream. Id.
at 3-29, 3-31.
    The physical effect that ``other waters'' have downstream is
less obvious than the physical connections of waters that are
adjacent or waters that are tributary, due to the physical distance
of ``other waters'' from the stream network. Despite this physical
distance, they are frequently connected in some degree through
either surface water or groundwater systems; over time, impacts in
one part of the hydrologic system will be felt in other parts. T.C.
Winter and J.W. LaBaugh, ``Hydrologic Considerations in Defining
Isolated Wetlands,'' Wetlands 23:532-540 (2003) at 538. For example,
``other waters'' that overspill into downstream water bodies during
times of abundant precipitation are connected over the long term.
Id. at 539. Wetlands that lack surface connectivity in a particular
season or year can, nonetheless, be highly connected in wetter
seasons or years. Report at 5-22 to 5-25. Many ``other waters''
interact with groundwater, either by receiving groundwater discharge
(flow of groundwater to the ``other water''), contributing to
groundwater recharge (flow of water from the ``other water'' to the
groundwater), or both. Id. at 5-23 (citing R.F. Lide, et al.,
``Hydrology of a Carolina Bay Located on the Upper Coastal Plain of
Western South Carolina,'' Wetlands 15:47-57 (1995); K.J. Devito, et
al., ``Groundwater Surface-Water Interactions in Headwater Forested
Wetlands of the Canadian Shield,'' Journal of Hydrology 181:127-47
(1996); R.K. Matheney and P.J. Gerla, ``Environmental Isotopic
Evidence for the Origins of Ground and Surface Water in a Prairie
Discharge Wetland,'' Wetlands 16:109-120 (1996); D.O. Rosenberry and
T.C. Winter, ``Dynamics of Water-Table Fluctuations in an Upland
between Two Prairie-Pothole Wetlands in North Dakota,'' Journal of
Hydrology 191:266-289 (1997); J.E. Pyzoha, et al., ``A Conceptual
Hydrologic Model for a Forested Carolina Bay Depressional Wetland on
the Coastal Plain of South Carolina, USA,'' Hydrological Processes
22:2689-2698 (2008)). Factors that determine whether a water
recharges groundwater or is a site of groundwater discharge include
topography, geology, soil features, and seasonal position of the
water table relative to the water. Id. at 5-24 (citing P.J. Phillips
and R.J. Shedlock, ``Hydrology and Chemistry of Groundwater and
Seasonal Ponds in the Atlantic Coastal-Plain in Delaware, USA,''
Journal of Hydrology 141:157-78 (1993); R.J. Shedlock, et al.,
``Interactions between Ground-Water and Wetlands, Southern Shore of
Lake-Michigan, USA,'' Journal of Hydrology 141:127-55 (1993); D.O.
Rosenberry and T.C. Winter, ``Dynamics of Water-Table Fluctuations
in an Upland Between two Prairie-Pothole Wetlands in North Dakota,''
Journal of Hydrology 191:266-89 (1997); J.E. Pyzoha, et al., ``A
Conceptual Hydrologic Model for a Forested Carolina Bay Depressional
Wetland on the Coastal Plain of South Carolina, USA,'' Hydrological
Processes 22: 2689-98 (2008)). Similarly, the magnitude and transit
time of groundwater flow from an ``other water'' to downstream
waters depend on several factors, including the intervening distance
and the properties of the rock or unconsolidated sediments between
the water bodies (i.e., the hydraulic conductivity of the material).
Id. at 5-24. Surface and groundwater hydrological connections are
those generating the capacity for ``other waters'' to affect
downstream waters, as water from the ``other water'' may contribute
to baseflow or stormflow through groundwater recharge. Id. at 5-25.
Contributions to baseflow are important for maintaining conditions
that support aquatic life in downstream waters. As discussed further
below, even in cases where waters lack a connection to downstream
waters, they can influence downstream water through water storage
and mitigation of peak flows. Id. at 5-36.
    The chemical effects that ``other waters'' have on downstream
waters are linked to their hydrologic connection downstream, though
a surface connection is not needed for a water to influence the
chemical integrity of the downstream water. Because the majority of
``other waters'' are hydrologically connected to downstream waters
via surface or groundwater connections, most ``other waters'' can
affect water quality downstream (although these connections do not
meet the definition of adjacency). D.F. Whigham and T. E. Jordan,
``Isolated Wetlands and Water Quality,'' Wetlands 23:541-549 (2003)
at 542. ``Other waters'' can act as sinks and transformers for
nitrogen and phosphorus, metals, pesticides, and other contaminants
that could otherwise negatively impact downstream waters. Report at
5-30 (citing R.R. Brooks, et al., ``Cobalt and Nickel Uptake by the
Nyssaceae,'' Taxon 26:197-201 (1977); H.F. Hemond, ``Biogeochemistry
of Thoreau's Bog, Concord, Massachusetts,'' Ecological Monographs
50:507-526 (1980); C.B. Davis, et al., ``Prairie Pothole Marshes as
Traps for Nitrogen and Phosphorus in Agricultural Runoff,'' in B.
Richardson, ed., Selected Proceedings of the Midwest Conference on
Wetland Values and Management, June 17-19, 1981, St. Paul, MN, (St.
Paul, MN: The Freshwater Society, 1981), pp. 153-163; H.F. Hemond,
``The Nitrogen Budget of Thoreau's Bog,'' Ecology 64:99-109 (1983);
K.C. Ewel and H.T. Odum, ed., Cypress Swamps, (Gainesville, Florida:
University of Florida Press, 1984); J.T. Moraghan, ``Loss and
Assimilation of 15N-nitrate Added to a North Dakota Cattail Marsh,''
Aquatic Botany 46:225-234 (1993); C.M. Kao, et al., ``Non-point
Source Pesticide Removal by a Mountainous Wetland,'' Water Science
and Technology 46:199-206 (2002); P.I. Boon, ``Biogeochemistry and
Bacterial Ecology of Hydrologically Dynamic Wetlands,'' in D.P.
Batzer and R.R. Sharitz, ed., Ecology of Freshwater and Estuarine
Wetlands (Berkeley, CA: University of California Press, 2006), pp.
115-176; E.J. Dunne, et al., ``Phosphorus Release and Retention by
Soils of Natural Isolated Wetlands,'' International Journal of
Environment and Pollution 28:496-516 (2006); T.E. Jordan, et al.,
``Comparing Functional Assessments of Wetlands to Measurements of
Soil Characteristics and Nitrogen Processing,'' Wetlands 27:479-497

(2007); S.L. Whitmire and S.K. Hamilton, ``Rates of Anaerobic
Microbial Metabolism in Wetlands of Divergent Hydrology on a Glacial
Landscape,'' Wetlands 28:703-714 (2008)). Also see, e.g., T.M.
Isenhart, Transformation and Fate of Nitrate in Northern Prairie
Wetlands, Ph.D. Dissertation (Ames, Iowa: Iowa State University,
1992). The body of published scientific literature and the Report
indicate that sink removal of nutrients and other pollutants by
``other waters'' is significant and geographically widespread.
Report at 5-30. Water quality characteristics of ``other waters''
are highly variable, depending primarily on the sources of water,
characteristics of the substrate, and land uses within the
watershed. D.F. Whigham and T.E. Jordan, ``Isolated Wetlands and
Water Quality,'' Wetlands 23:541-549 (2003) at 541. These variables
inform whether an ``other water'' has a significant nexus to an
(a)(1) through (a)(3) water. For instance, some prairie potholes may
improve water quality and may efficiently retain nutrients that
might otherwise cause water quality problems downstream; in such
systems it may be their lack of a direct hydrologic connection that
enables the prairie potholes to more effectively retain nutrients.
Id. at 543.
    ``Other waters'' can be biologically connected to each other and
to downstream waters through the movement of seeds,
macroinvertebrates, amphibians, reptiles, birds, and mammals. Report
at 5-31 to 5-33; S.G. Leibowitz, ``Isolated Wetlands and Their
Functions: An Ecological Perspective,'' Wetlands 23:517-531 (2003)
at 519. The movement of organisms between ``other waters'' and
downstream waters is governed by many of the same factors that
affect movement of organisms between adjacent wetlands and
downstream waters (See Part II Section 2.A.d.). Report at 5-31.
Generally, ``other waters'' are further away from stream channels
than adjacent waters, making hydrologic connectivity less frequent,
and increasing the number and variety of landscape barriers over
which organisms must disperse. Id. Plants, though non-mobile, have
evolved many adaptations to achieve dispersal over a variety of
distances, including water-borne dispersal during periodic
hydrologic connections, ``hitchhiking'' on or inside highly mobile
animals, and more typically via wind dispersal of seeds and/or
pollen. Id. at 5-31 (citing S.M. Galatowitsch and A.G. van der Valk,
``The Vegetation of Restored and Natural Prairie
Wetlands,''Ecological Applications 6:102-112 (1996); H.R. Murkin and
P.J. Caldwell, ``Avian Use of Prairie Wetlands,'' in H.R. Murkin, et
al., ed., Prairie Wetland Ecology: The Contribution of the Marsh
Ecology Research Program, (Ames, IA: Iowa State University Press,
2000), pp. 249-286; J.M. Amezaga, et al., ``Biotic Wetland
Connectivity--Supporting a New Approach for Wetland Policy,'' Acta
Oecologica-International Journal of Ecology 23:213-222 (2002); J.
Figuerola and A.J. Green, ``Dispersal of Aquatic Organisms by
Waterbirds: a Review of Past Research and Priorities for Future
Studies,'' Freshwater Biology 47:483-494 (2002); M.B. Soons and G.W.
Heil, ``Reduced Colonization Capacity in Fragmented Populations of
Wind-Dispersed Grassland Forbs,'' Journal of Ecology 90:1033-1043
(2002); M.B. Soons, ``Wind Dispersal in Freshwater Wetlands:
Knowledge for Conservation and Restoration,'' Applied Vegetation
Science 9:271-278 (2006); C. Nilsson, et al., ``The Role of
Hydrochory in Structuring Riparian and Wetland Vegetation,''
Biological Reviews 85:837-858 (2010)). Mammals that disperse
overland can also contribute to connectivity and can act as
transport vectors for hitchhikers such as algae. Id. at 5-32 (citing
C.E. Shanks and G.C. Arthur, ``Muskrat Movements and Population
Dynamics in Missouri Farm Ponds and Streams,'' Journal of Wildlife
Management 16:138-148 (1952); J.P. Roscher, ``Alga Dispersal by
Muskrat Intestinal Contents,'' Transactions of the American
Microscopical Society 86:497-498 (1967); W.R. Clark, ``Ecology of
Muskrats in Prairie Wetlands,'' in H. R. Murkin, et al., ed., 2000,
pp. 287-313)). Invertebrates also utilize birds and mamals to
hitchhike, and these hitchhikers can be an important factor
structuring invertebrate metapopulations in ``other waters'' and in
aquatic habitats separated by hundreds of kilometers. Id. (citing J.
Figuerola and A.J. Green, ``Dispersal of Aquatic Organisms by
Waterbirds: A Review of Past Research and Priorities for Future
Studies,'' Freshwater Biology 47:483-494 (2002); J. Figuerola, et
al., ``Invertebrate Eggs Can Fly: Evidence of Waterfowl-Mediated
Gene Flow in Aquatic Invertebrates,'' American Naturalist 165:274-
280 (2005); M.R. Allen, ``Measuring and Modeling Dispersal of Adult
Zooplankton,'' Oecologia 153:135-143 (2007); D. Frisch, et al.,
``High Dispersal Capacity of a Broad Spectrum of Aquatic
Invertebrates Via Waterbirds,'' Aquatic Sciences 69:568-574 (2007)).
Numerous flight-capable insects use both ``other waters'' and
downstream waters; these insects move outside the tributary network
to find suitable habitat for overwintering, refuge from adverse
conditions, hunting, foraging, or breeding, and then can return back
to the tributary network for other lifecycle needs. Id. at 5-33
(citing D.D. Williams, ``Environmental Constraints in Temporary
Fresh Waters and Their Consequences for the Insect Fauna,'' Journal
of the North American Benthological Society 15:634-650 (1996); A.J.
Bohonak and D.G. Jenkins, ``Ecological and Evolutionary Significance
of Dispersal by Freshwater Invertebrates,'' Ecology Letters 6:783-
796 (2003)). Amphibians and reptiles also move between ``other
waters'' and downstream waters to satisfy part of their life history
requirements. Id. at 5-33. Alligators in the Southeast, for
instance, can move from tributaries to shallow, seasonal limesink
wetlands for nesting, and also use these wetlands as nurseries for
juveniles; sub-adults then shift back to the tributary network
through overland movements. Id. (citing A.L. Subalusky, et al.,
``Ontogenetic Niche Shifts in the American Alligator Establish
Functional Connectivity between Aquatic Systems,'' Biological
Conservation 142:1507-1514 (2009); A.L. Subalusky, et al.,
``Detection of American Alligators in Isolated, Seasonal Wetlands,''
Applied Herpetology 6:199-210 (2009)). Similarly, amphibians and
small reptile species, such as frogs, toads, and newts, commonly use
both tributaries and ``other waters,'' during one or more stages of
their life cycle, and can at times disperse over long distances. Id.
(citing V.S. Lamoureux and D.M. Madison, ``Overwintering Habitats of
Radio-Implanted Green Frogs, Rana clamitans,'' Journal of
Herpetology 33:430-435 (1999); K.J. Babbitt, et al., ``Patterns of
Larval Amphibian Distribution along a Wetland Hydroperiod
Gradient,'' Canadian Journal of Zoology-Revue Canadienne De Zoologie
81:1539-1552 (2003); S.B. Adams, et al., ``Instream Movements by
Boreal Toads (Bufo boreas boreas),'' Herpetological Review 36:27-33
(2005); D.M. Green, ``Bufo americanus, American Toad,'' in M.
Lannoo, ed., Amphibian Declines: The Conservation Status of the
United States Species (Berkeley, CA: University of California Press,
2005), pp. 692-704; T.W. Hunsinger and M. J. Lannoo, ``Notophthalmus
viridescens, Eastern Newt,'' in M. Lannoo, ed., 2005, pp. 912-914;
J.W. Petranka and C.T. Holbrook, ``Wetland Restoration for
Amphibians: Should Local Sites Be Designed to Support
Metapopulations or Patchy Populations?,'' Restoration Ecology
14:404-411 (2006)).
    Even when a surface or groundwater hydrologic connection between
a water and a downstream water is visibly absent, many waters still
have the ability to substantially influence the integrity of
downstream waters. However, such circumstances would be uncommon.
Id. at 5-22 to 5-25. Aquatic systems that may seem disconnected
hydrologically are often connected but at irregular timeframes or
through subsurface flow, and perform important functions that can be
vital to the chemical, physical, or biological integrity of
downstream waters. Some wetlands that are not adjacent may be
hydrologically disconnected most of the time but connected to the
stream network during rare high-flow events. The lack of a
hydrologic connection also allows for water storage in ``other
waters,'' attenuating peak streamflows, and, thus, downstream
flooding, and also reducing nutrient and soil pollution in
downstream waters. Report at 5-25 to 5-26, 5-36. Prairie potholes a
great distance from any tributary, for example, are thought to store
significant amounts of runoff. Id. at 5-36 (citing R.P. Novitzki,
``Hydrologic Characteristics of Wisconsin's Wetlands and Their
Influence on Floods,'' in P. Greeson, et al., ed., Wetland Functions
and Values: The Status of Our Understanding, Proceedings of the
National Symposium on Wetlands (Minneapolis, MN: American Water
Resources Association, 1979), pp. 377-388; D.E. Hubbard and R.L.
Linder, ``Spring Runoff Retention in Prairie Pothole Wetlands,''
Journal of Soil and Water Conservation 41:122-125 (1986); J. Jacques
and D.L. Lorenz, ``Techniques for Estimating the Magnitude and
Frequency of Floods in Minnesota,'' Water Resources Investigations
Report 87-4170, (St. Paul, MN: U.S. Geological Survey, 1988); K.C.
Vining, ``Simulation of Streamflow and Wetland Storage, Starkweather
Coulee Subbasin, North Dakota, Water Years 1981-98,'' Water-
Resources Investigations Report 02-4113 (Bismarck, North Dakota:
U.S. Geological

Survey, 2002); R.A. Gleason, et al., Estimating Water Storage
Capacity of Existing and Potentially Restorable Wetland Depressions
in a Subbasin of the Red River of the North, U.S. Geological Survey
Open-File Report 2007-1159 (Reston, VA: U.S. Geological Survey,
2007); D.L. Lorenz, et al., ``Techniques for Estimating the
Magnitude and Frequency of Peak Flows on Small Streams in Minnesota
Based on Through Water Year 2005,'' USGS Scientific Investigations
Report 2009-5250, (Reston, VA: U.S. Geological Survey, 2010)).
Filling wetlands reduces water storage capacity in the landscape and
causes runoff from rainstorms to overwhelm the remaining available
water conveyance system. See, e.g., C.A. Johnston, et al., ``The
Cumulative Effect of Wetlands on Stream Water Quality and
Quantity,'' Biogeochemistry 10:105-141 (1990); A.L. Moscrip and D.R.
Montgomery, ``Urbanization, Flood Frequency, and Salmon Abundance in
Puget Lowland Streams,'' Journal of the American Water Resources
Association 33:1289-1297 (1997); N.E. Detenbeck, et al.,
``Evaluating Perturbations and Developing Restoration Strategies for
Inland Wetlands in the Great Lakes Basin,'' Wetlands 19(4): 789-820
(1999); N.E. Beck, et al., ``Relationship of Stream Flow Regime in
the Western Lake Superior Basin to Watershed Type Characteristics,''
Journal of Hydrology 309(1-4): 258-276 (2005). Wetlands, even when
lacking a hydrologic connection downstream, improve downstream water
quality by accumulating nutrients, trapping sediments, and
transforming a variety of substances. See, e.g., National Research
Council, Wetlands: Characteristics and Boundaries (Washington, DC:
National Academy Press, 1995), p. 38.
    Under today's proposal, on a case-specific basis, ``other
waters'' that have a significant nexus to an (a)(1) through (a)(3)
water are ``waters of the United States'' under (a)(7). The
scientific literature and data in the Report and elsewhere support
that some ``other waters'' (including some of those in the case
studies), along with other similarly situated waters in the region,
do greatly affect the chemical, physical, or biological integrity of
(a)(1) through (a)(3) waters, and thus would be jurisdictional under
(a)(7).
    Though much of the literature cited in the Report relates to
``other waters'' that are wetlands, the Report indicates that non-
wetland waters that are not (a)(1) through (a)(6) waters also can
have chemical, physical, or biological connections that
significantly impact downstream waters. For instance, non-adjacent
ponds or lakes that are not part of the tributary network can still
be connected to downstream waters through chemical, physical, and
biological connections. Lake storage has been found to attenuate
peak streamflows in Minnesota. Id. at 5-25 (citing J. Jacques and
D.L. Lorenz, Techniques for Estimating the Magnitude and Frequency
of Floods of Ungauged Streams in Minnesota, USGS Water-Resources
Investigations Report 84-4170 (Washington, DC: U.S. Geological
Survey, 1988); D.L. Lorenz, et al., Techniques for Estimating the
Magnitude and Frequency of Peak Flows on Small Streams in Minnesota
Based on Data through Water Year 2005, U.S. Geological Survey
Scientific Investigations Report 2009-5250 (Reston, VA: U.S.
Geological Survey, 2010)). Similar to wetlands, ponds are often used
by invertebrate, reptile, and amphibian species that also utilized
downstream waters for various life history requirements,
particularly because many ponds, particularly temporary ponds, are
free of predators, such as fish, that prey on larvae. The American
toad and Eastern newt are widespread habitat generalists that can
move among streams, wetlands, and ponds to take advantage of each
aquatic habitat, feeding on aquatic invertebrate prey, and avoiding
predators. See, e.g., Id. at 5-33 (citing K.J. Babbitt et al.,
``Patterns of Larval Amphibian Distribution along a Wetland
Hydroperiod Gradient,'' Canadian Journal of Zoology-Revue Canadienne
De Zoologie 81:1539-1552 (2003); D.M. Green, ``Bufo americanus,
American Toad,'' in M. Lannoo, ed., Amphibian Declines: The
Conservation Status of United States Species, (Berkeley, CA:
University of California Press, 2005), pp. 692-704; T.W. Hunsinger
and M.J. Lannoo, ``Notophthalmus viridescens, Eastern Newt,'' in M.
Lannoo, ed., Amphibian Declines: The Conservation Status of United
States Species, (Berkeley, CA: University of California Press,
2005), pp. 912-914; J.W. Petranka and C.T. Holbrook, ``Wetland
Restoration for Amphibians: Should Local Sites Be Designed to
Support Metapopulations or Patchy Populations?,'' Restoration
Ecology 14:404-411 (2006)). Additionally, stream networks that are
not part of the tributary system (e.g., streams in closed basins
without an (a)(1) through (a)(3) water or losing streams and other
streams that cease to flow before reaching downstream (a)(1) through
(a)(3) waters) may likewise have a significant impact on the
chemical, physical, or biological integrity of downstream waters.
Non-tributary streams may be connected via groundwater to downstream
waters. Such streams may also provide habitat to insect, amphibian,
and reptile species that also use the tributary network.

i. Additional Request for Public Comment on ``Other Waters''

    The agencies are considering whether to determine by rule that
prairie potholes, Carolina and Delmarva bays, pocosins, Texas
coastal prairie wetlands, western vernal pools, and perhaps other
categories of waters, either alone or in combination with ``other
waters'' of the same type in a single point of entry watershed have
a significant nexus and are jurisdictional. R.W. Tiner,
``Geographically Isolated Wetlands of the United States,'' Wetlands
23(3):494-516 (2003); M.G. Forbes, et al., ``Nutrient Transformation
and Retention by Coastal Prairie Wetlands, Upper Gulf Coast,
Texas,'' Wetlands 32(4): 705-715 (2012). These waters would not
require a case-by-case analysis. At the same time, the agencies
could determine by rule that playa lakes, and perhaps other
categories of waters, do not have a significant nexus and are not
jurisdictional. These waters would not be subject to a case-by-case
analysis of significant nexus. As the science develops, the agencies
may determine that additional categories of ``other waters'' have a
significant nexus and are thus categorically jurisdictional. The
specific categories of ``other waters'' for which there is currently
evidence of a significant nexus are discussed below:
    a. Prairie potholes are a complex of glacially formed wetlands,
usually occurring in depressions that lack permanent natural
outlets, that are found in the central United States and Canada.
Report at 5-57. The vast area they occupy is variable in many
aspects, including climatically, topographically, geologically, and
in terms of land use and alteration, which imparts variation on the
potholes themselves. Prairie potholes demonstrate a wide range of
hydrologic permanence, from holding permanent standing water to
wetting only in years with high precipitation, which in turn
influences the diversity and structure of their biological
communities. Owing in large part to their spatial and temporal
variability, individual prairie potholes span the entire continuum
of connectivity to and isolation from the river network and other
bodies of water. Potholes generally accumulate and retain water
effectively due to the low permeability of their underlying soil,
which can modulate flow characteristics of nearby streams and
rivers. Potholes also can accumulate chemicals in overland flow,
thereby reducing chemical loading to other bodies of water. When
potholes are artificially connected to streams and lakes through
drainage, isolation is eliminated and they become sources of water
and chemicals. Potholes also support a community of highly mobile
organisms, from plants to invertebrates that move among potholes and
that can biologically connect the entire complex to the river
network. Based on these connections and the strength of their
effects, individually or in combination with other prairie potholes
in the watershed, on the chemical, physical, or biological integrity
of an (a)(1) through (a)(3) water, the agencies could conclude by
rule that prairie potholes have a significant nexus and are
jurisdictional. The agencies' determination will be informed by the
final version of the Report and other available scientific
information.
    b. Carolina and Delmarva bays are ponded depressional wetlands
that occur along the Atlantic coastal plain from northern Florida to
New Jersey. Id. at 5-49. Most bays receive water through
precipitation, lose water through evapotranspiration, and lack
natural surface outlets. Both mineral-based and peat-based bays have
shown connections to shallow groundwater. Bays typically are in
proximity to each other or to open waters, providing the potential
for surface water connections in large rain events via overland
flow. Fish are reported in bays that are known to dry out,
indirectly demonstrating surficial connections. Amphibians and
reptiles use bays extensively for breeding and for rearing young.
These animals can disperse many meters on the landscape and can
colonize, or serve as a food source to, downstream waters.
Similarly, bays foster abundant insects that have the potential to
become part of the downstream food chain. Humans have ditched and
channelized a high percentage of bays, creating new surface
connections to ``other waters'' and allowing

transfer of nutrients, sediment, and other pollutants such as
methylmercury. Based on these connections and the strength of their
effects, individually or in combination with other Carolina or
Delmarva bays in the watershed, on the chemical, physical, or
biological integrity of an (a)(1) through (a)(3) water, the agencies
could conclude by rule that Carolina and Delmarva bays have a
significant nexus and are jurisdictional. The agencies'
determination will be informed by the final version of the Report
and other available scientific information.
    c. Vernal pools are shallow, seasonal wetlands that accumulate
water during colder, wetter months and gradually dry up during
warmer, drier months. Id. at 5-66. Western vernal pools are seasonal
wetlands associated with topographic depressions, soils with poor
drainage, mild, wet winters and hot, dry summers in western North
America from southeastern Oregon to northern Baja California, Mexico
(Id. at 5-67, citing E.T. Bauder and S. McMillan, ``Current
Distribution and Historical Extent of Vernal Pools in Southern
California and Northern Baja California, Mexico,'' pp. 56-70 in C.W.
Witham, et al., editors, Ecology, Conservation, and Management,
1998). Because their hydrology and ecology are so tightly coupled
with the local and regional geological processes that formed them,
western vernal pools typically occur within ``vernal pool
landscapes,'' or complexes of pools in which swales connect pools to
each other and to seasonal streams (Id. at 5-67 to 5-68, citing W.A.
Weitkamp, et al., ``Pedogenesis of a Vernal Pool Entisol-Alfisol-
Vertisol Catena in Southern California,'' Soil Science Society of
America Journal 60:316323 (1996); D.W. Smith and W.L. Verrill,
``Vernal Pool-Soil-Landform Relationships in the Central Valley,
California,'' pp. 15-23 in C.W. Witham, et al., editors, Ecology,
Conservation, and Management of Vernal Pool Ecosystems--Proceedings
from a 1996 Conference (California Native Plant Society, Sacramento,
CA,1998); M.C. Rains, et al., ``The Role of Perched Aquifers in
Hydrological Connectivity and Biogeochemical Processes in Vernal
Pool Landscapes, Central Valley, California,'' Hydrological
Processes 20:1157-1175 (2008)). Despite differences in geology,
climate, and biological communities, some common findings about the
hydrologic connectivity of vernal pools in different regions,
including Western vernal pools, include evidence for temporary or
permanent outlets, frequent filling and spilling of higher pools
into lower elevation swales and stream channels, and conditions
supporting subsurface flows through pools without perched aquifers
to nearby streams. Non-glaciated vernal pools in western states are
reservoirs of biodiversity and can be connected genetically to other
locations and aquatic habitats through wind- and animal-mediated
dispersal. Based on these connections and the strength of their
effects, individually or in combination with other western vernal
pools in the watershed, on the chemical, physical, or biological
integrity of an (a)(1) through (a)(3) water, the agencies could
conclude by rule that western vernal pools have a significant nexus
and are jurisdictional. The agencies' determination will be informed
by the final version of the Report and other available scientific
information. The jurisdictional status of vernal pools located in
other areas will be determined on a case-by-case significant nexus
analysis with any similar situated waters in the single point of
entry watershed. For example, insects and amphibians that can live
in streams or permanent pools opportunistically use glaciated vernal
pools in the Northeast and Midwest as alternative breeding habitat,
refuge from predators or environmental stressors, hunting or
foraging habitat, or stepping-stone corridors for dispersal and
migration.
    d. The word pocosin comes from the Algonquin Native American
word for ``swamp on a hill,'' and these evergreen shrub and tree
dominated landscapes are found from Virginia to northern Florida,
but mainly in North Carolina. (C.J. Richardson, ``Pocosins:
Hydrologically Isolated or Integrated Wetlands on the Landscape?,''
Wetlands 23(3):563-576 (2003)). Usually, there is no standing water
present in these peat-accumulating wetlands, but a shallow water
table leaves the soil saturated for much of the year. They range in
size from less than an acre to several thousand acres. The slow
movement of water through the dense organic matter in pocosins
removes excess nutrients deposited by rainwater. The same organic
matter also acidifies the water. This pure water is slowly released
to downstream waters and estuaries, where it helps to maintain the
proper salinity, nutrients, and acidity. (Id.) Because pocosins are
the topographic high areas on the regional landscape, they serve as
the source of water for downstream areas. Pocosins often have
seasonal connections to drainageways leading to estuaries or are
contiguous with other wetlands draining into perennial streams or
estuaries. (R.W. Tiner, ``Geographically Isolated Wetlands of the
United States,'' Wetlands 23(3):494-516 (2003)). Other pocosins have
been ditched and are directly connected to streams. (Id.) The
draining of pocosins and decreased salinity in estuaries may be
having a negative effect on brown shrimp in North Carolina. (Id.)
Based on these connections and the strength of their effects,
individually or in combination with other pocosins in the watershed,
on the chemical, physical, or biological integrity of an (a)(1)
through (a)(3) water, the agencies could conclude by rule pocosins
have a significant nexus and are jurisdictional. The agencies'
determination will be informed by the final version of the Report
and other available scientific information.
    e. Along the Gulf of Mexico from western Louisiana to south
Texas, freshwater wetlands occur as a mosaic of depressions, ridges,
intermound flats, and mima mounds. (M.G. Forbes, et al., ``Nutrient
Transformation and Retention by Coastal Prairie Wetlands, Upper Gulf
Coast, Texas,'' Wetlands 32(4): 705-715 (2012)). These coastal
prairie wetlands were formed thousands of years ago by ancient
rivers and bayous and once occupied almost a third of the landscape
around Galveston Bay, Texas. Texas coastal prairie wetlands are
locally abundant and in close proximity to other coastal prairie
wetlands and function together cumulatively. (N. Enwright, et al.,
``Using Geographic Information Systems (GIS) to Inventory Coastal
Prairie Wetlands Along the Upper Gulf Coast, Texas,'' Wetlands
31:687-697 (2011)). Collectively as a complex, Texas coastal prairie
wetlands may be geographically and hydrologically connected to each
other via swales and connected to downstream waters, contributing
flow to those downstream waters. (B.P. Wilcox, et al., ``Evidence of
Surface Connectivity for Texas Gulf Coast Depressional Wetlands,''
Wetlands 31(3):451-458 (2011)). Cumulatively, these wetlands can
control nutrient release levels and rates to downstream waters, as
they capture, store, transform and pulse releases of nutrients to
those waters. (M.G. Forbes, et al., ``Nutrient Transformation and
Retention by Coastal Prairie Wetlands, Upper Gulf Coast, Texas,''
Wetlands 32(4): 705-715 (2012)). Based on these connections and the
strength of their effects, individually or in combination with other
coastal prairie wetlands in the watershed, on the chemical,
physical, or biological integrity of an (a)(1) through (a)(3) water,
the agencies could conclude by rule Texas coastal prairie wetlands
have a significant nexus and are jurisdictional. The agencies'
determination will be informed by the final version of the Report
and other available scientific information.
    The agencies could also conclude that playa lakes in the Great
Plains even in combination with other playa lakes in a single point
of entry watershed always lack a significant nexus and therefore are
not jurisdictional. Playa lakes are round, shallow wetlands found
primarily in the High Plains, a subregion of the Great Plains in the
western and Midwestern United States. (D.A. Haukos, and L.M. Smith,
``Past and Future Impacts of Wetland Regulations on Playas,''
Wetlands 23(3):577-589 (2003); R.W. Tiner, ``Geographically Isolated
Wetlands of the United States,'' Wetlands 23(3):494-516 (2003)).
Each playa typically occurs within a closed or terminal watershed,
where all water in the watershed drains to the playa. (D.A. Haukos,
and L.M. Smith, ``Past and Future Impacts of Wetland Regulations on
Playas,'' Wetlands 23(3):577-589 (2003)). As such, playas typically
do not drain to an (a)(1) through (a)(3) water. Most playas are fed
by precipitation and associated runoff, though a few are fed by
groundwater. (R.W. Tiner, ``Geographically Isolated Wetlands of the
United States,'' Wetlands 23(3):494-516 (2003)). Most playas fill
with water only after spring rainstorms when freshwater collects in
the round depressions of the otherwise flat landscape of west Texas,
Oklahoma, New Mexico, Colorado, and Kansas. Although playas play a
role in groundwater recharge of the Ogallala Aquifer, in local
floodwater storage, and in provision of wildlife habitat, available
scientific literature indicates that their chemical, physical, or
biological connections to and effects on (a)(1) through (a)(3)
waters are of a limited and tenuous nature.
    The agencies seek comment, data, and information on whether
there are

subcategories of ``other waters'' or specific combinations of
characteristics that are ``likely, in the majority of cases, to
perform important functions for an aquatic ecosystem incorporating
navigable waters,'' and, thus, should be per se jurisdictional. For
example, if there are additional studies addressing the connectivity
of prairie potholes in the Red River Valley, including the factors
influencing that connectivity and how it is important to particular
downstream waters, that would be relevant information.

Appendix B

Legal Analysis

Background

    Congress enacted the Federal Water Pollution Control Act
Amendments of 1972, Public Law 92-500, 86 Stat. 816, as amended, (33
U.S.C. 1251 et seq.) (Clean Water Act or CWA) ``to restore and
maintain the chemical, physical, and biological integrity of the
Nation's waters.'' 33 U.S.C. 1251(a).\9\ The U.S. Supreme Court
first addressed the scope of ``waters of the United States''
protected by the CWA in United States v. Riverside Bayview Homes,
474 U.S. 121 (1985), which involved wetlands adjacent to a
traditional navigable water in Michigan. In a unanimous opinion, the
Court deferred to the Corps' ecological judgment that adjacent
wetlands are ``inseparably bound up'' with the waters to which they
are adjacent, and upheld the inclusion of adjacent wetlands in the
regulatory definition of ``waters of the United States.'' Id. at
134. The Court observed that the broad objective of the CWA to
restore and maintain the integrity of the Nation's waters
``incorporated a broad, systemic view of the goal of maintaining and
improving water quality. . . . Protection of aquatic ecosystems,
Congress recognized, demanded broad federal authority to control
pollution, for `[w]ater moves in hydrologic cycles and it is
essential that discharge of pollutants be controlled at the source.'
In keeping with these views, Congress chose to define the waters
covered by the Act broadly.'' Id. at 132-33 (citing Senate Report
92-414).
---------------------------------------------------------------------------

    \9\ The 1972 legislation extensively amended the Federal Water
Pollution Control Act (FWPCA), which was originally enacted in 1948.
Further amendments to the FWPCA enacted in 1977 acknowledged the
popular name of the statute as the Clean Water Act. See Public Law
95-217, 91 Stat. 1566; 33 U.S.C. 1251 note.
---------------------------------------------------------------------------

    The issue of CWA jurisdiction over ``waters of the United
States'' was addressed again by the Supreme Court in Solid Waste
Agency of Northern Cook County v. U.S. Army Corps of Engineers, 531
U.S. 159 (2001) (SWANCC). In SWANCC, the Court (in a 5-4 opinion)
held that the use of ``isolated'' nonnavigable intrastate ponds by
migratory birds was not by itself a sufficient basis for the
exercise of Federal regulatory authority under the CWA. The SWANCC
Court noted that in Riverside it had ``found that Congress' concern
for the protection of water quality and aquatic ecosystems indicated
its intent to regulate wetlands `inseparably bound up' with the
`waters of the United States' '' and that ``it was the significant
nexus between the wetlands and `navigable waters' that informed our
reading of the CWA'' in that case. Id. at 167. SWANCC did not
invalidate (a)(3) or other parts of the regulatory definition of
``waters of the United States.''
    Five years after SWANCC, the Court again addressed the CWA term
``waters of the United States'' in Rapanos v. United States, 547
U.S. 715 (2006). Rapanos involved two consolidated cases in which
the CWA had been applied to wetlands adjacent to nonnavigable
tributaries of traditional navigable waters. All Members of the
Court agreed that the term ``waters of the United States''
encompasses some waters that are not navigable in the traditional
sense. A four-Justice plurality in Rapanos interpreted the term
``waters of the United States'' as covering ``relatively permanent,
standing or continuously flowing bodies of water . . . ,'' id. at
739, that are connected to traditional navigable waters, id. at 742,
as well as wetlands with a ``continuous surface connection . . .''
to such water bodies, id. (Scalia, J., plurality opinion). The
Rapanos plurality noted that its reference to ``relatively
permanent'' waters did ``not necessarily exclude streams, rivers, or
lakes that might dry up in extraordinary circumstances, such as
drought,'' or ``seasonal rivers, which contain continuous flow
during some months of the year but no flow during dry months . . .
.'' Id. at 732 n.5 (emphasis in original). Justice Kennedy's
concurring opinion took a different approach. Justice Kennedy
concluded that ``to constitute `navigable waters' under the Act, a
water or wetland must possess a `significant nexus' to waters that
are or were navigable in fact or that could reasonably be so made.''
Id. at 759 (citing SWANCC, 531 U.S. at 167, 172). He concluded that
wetlands possess the requisite significant nexus if the wetlands
``either alone or in combination with similarly situated [wet]lands
in the region, significantly affect the chemical, physical, and
biological integrity of other covered waters more readily understood
as `navigable.' '' 547 U.S. at 780. Justice Kennedy's opinion notes
that such a relationship with navigable waters must be more than
``speculative or insubstantial.'' Id. at 780. In Rapanos, the four
dissenting Justices, who would have affirmed the court of appeals'
application of the pertinent regulatory provisions, concluded that
the term ``waters of the United States'' encompasses, inter alia,
all tributaries and wetlands that satisfy either the plurality's
standard or that of Justice Kennedy. Id. at 810 & n.14 (Stevens, J.,
dissenting). Neither the plurality nor the Kennedy opinions
invalidated any of the regulatory provisions defining ``waters of
the United States.''
    The Circuit Courts of Appeals are not uniform as to the
controlling standard for ``waters of the United States'' under
Rapanos. The First, Third and Eighth Circuits have concluded that
CWA jurisdiction exists if either Justice Kennedy's standard or the
plurality's standard is met. United States v. Johnson, 467 F.3d 56,
66 (1st Cir. 2006), cert. denied, 552 U.S. 948 (2007); U.S. v.
Donovan, 661 F.3d. 174, 176 (3rd Cir. 2011), cert. denied, 132 S.Ct.
2409 (2012); U.S. v. Bailey, 571 F.3d 791, 798-99 (8th Cir. 2009).
The Seventh and Ninth Circuits limited their holdings that the
Kennedy standard applied to the facts of the cases before them, and
did not foreclose the possibility that in some cases the plurality's
standard might apply. N. Cal. River Watch v. City of Healdsburg, 496
F.3d 993, 999-1000 (9th Cir. 2007), cert. denied, 552 U.S. 1180
(2008); United States v. Gerke Excavating, Inc., 464 F.3d 723, 725
(7th Cir. 2006), cert. denied, 552 U.S. 810 (2007). The Fifth and
Sixth Circuits did not choose a controlling standard because the
waters at issue satisfied both standards. United States v. Lucas,
516 F.3d 316, 326-27 (5th Cir. 2008), cert. denied, 555 U.S. 822
(2008); United States v. Cundiff, 555 F.3d 200, 210-13 (6th Cir.
2009), cert. denied, 558 U.S. 818 (2009). The Eleventh Circuit has
held that only the Kennedy standard determines jurisdiction. United
States v. Robison, 505 F.3d 1208 (11th Cir. 2007), cert. denied sub
nom United States v. McWane and McWane v. United States, 555 U.S.
1045 (2008). No Circuit Court has held that only the plurality
standard applies.

Traditional Navigable Waters

    EPA and the Corps are proposing no changes to the existing
regulation related to traditional navigable waters and at paragraph
(a)(1) will continue to assert jurisdiction over all waters which
are currently used, or were used in the past, or may be susceptible
to use in interstate or foreign commerce, including all waters which
are subject to the ebb and flow of the tide. See e.g., 33 CFR
328.3(a)(1); 40 CFR 230.3(s)(1); 40 CFR 122.2 (``waters of the
U.S.'')). These ``(a)(1) waters'' are the ``traditional navigable
waters.'' These (a)(1) waters include all of the waters defined in
33 CFR part 329, which implements sections 9 and 10 of the Rivers
and Harbors Act, and by numerous decisions of the Federal courts,
plus all other waters that are navigable-in-fact (e.g., the Great
Salt Lake, UT and Lake Minnetonka, MN).
    To determine whether a water body constitutes an (a)(1) water
under the regulations, relevant considerations include Corps
regulations, prior determinations by the Corps and by the Federal
courts, and case law. Corps districts and EPA regions would
determine whether a particular water body is a traditional navigable
water based on application of those considerations to the specific
facts in each case.
    As noted above, the (a)(1) waters include, but are not limited
to, waters that meet any of the tests set forth in 33 CFR part 329
(e.g., the water body is (a) subject to the ebb and flow of the
tide, and/or (b) the water body is presently used, or has been used
in the past, or may be susceptible for use (with or without
reasonable improvements) to transport interstate or foreign
commerce). The Corps districts have made determinations in the past
under these regulations for purposes of asserting jurisdiction under
sections 9 and 10 of the Rivers and Harbors Act of 1899 (33 U.S.C.
401 and 403). Pursuant to 33 CFR 329.16, the Corps maintains lists
of final determinations of navigability for purposes of Corps
jurisdiction under the Rivers and Harbors Act of 1899. While absence
from the list should not be taken as an indication that the water is
not navigable (Sec.  329.16(b)), Corps districts and EPA Regions
rely on any final Corps

determination that a water body meets any of the tests set forth in
part 329.
    If the Federal courts have determined that a water body is
navigable-in-fact under Federal law for any purpose, that water body
qualifies as a ``traditional navigable water'' subject to CWA
jurisdiction under 33 CFR 328.3(a)(1) and 40 CFR 230.3(s)(1). Corps
districts and EPA regions are guided by the relevant opinions of the
Federal courts in determining whether such water bodies are
``currently used, or were used in the past, or may be susceptible to
use in interstate or foreign commerce'' (33 CFR 328.3(a)(1); 40 CFR
230.3(s)(1)) or ``navigable-in-fact.''
    The definition of ``navigable-in-fact'' derives from a long line
of cases originating with The Daniel Ball, 77 U.S. 557 (1870). The
Supreme Court stated:

Those rivers must be regarded as public navigable rivers in law
which are navigable in fact. And they are navigable in fact when
they are used, or are susceptible of being used, in their ordinary
condition, as highways for commerce, over which trade and travel are
or may be conducted in the customary modes of trade and travel on
water.

The Daniel Ball, 77 U.S. at 563.
    In The Montello, the Supreme Court clarified that ``customary
modes of trade and travel on water'' encompasses more than just
navigation by larger vessels:

The capability of use by the public for purposes of transportation
and commerce affords the true criterion of the navigability of a
river, rather than the extent and manner of that use. If it be
capable in its natural state of being used for purposes of commerce,
no matter in what mode the commerce may be conducted, it is
navigable in fact, and becomes in law a public river or highway.

The Montello, 87 U.S. 430, 441-42 (1874). In that case, the Court
held that early fur trading using canoes sufficiently showed that
the Fox River was a navigable water of the United States. The Court
was careful to note that the bare fact of a water's capacity for
navigation alone is not sufficient; that capacity must be indicative
of the water's being ``generally and commonly useful to some purpose
of trade or agriculture.'' Id. at 442.
    In Economy Light & Power, the Supreme Court held that a waterway
need not be continuously navigable; it is navigable even if it has
``occasional natural obstructions or portages'' and even if it is
not navigable ``at all seasons . . . or at all stages of the
water.'' Economy Light & Power Co. v. U.S., 256 U.S. 113, 122
(1921).
    In United States v. Holt State Bank, 270 U.S. 49 (1926), the
Supreme Court summarized the law on navigability as of 1926 as
follows:

The rule long since approved by this court in applying the
Constitution and laws of the United States is that streams or lakes
which are navigable in fact must be regarded as navigable in law;
that they are navigable in fact when they are used, or are
susceptible of being used, in their natural and ordinary condition,
as highways for commerce, over which trade and travel are or may be
conducted in the customary modes of trade and travel on water; and
further that navigability does not depend on the particular mode in
which such use is or may be had--whether by steamboats, sailing
vessels or flatboats--nor on an absence of occasional difficulties
in navigation, but on the fact, if it be a fact, that the stream in
its natural and ordinary condition affords a channel for useful
commerce.

Holt State Bank, 270 U.S. at 56.
    In U.S. v. Utah, 283 U.S. 64 (1931) and U.S. v. Appalachian
Elec. Power Co, 311 U.S. 377 (1940), the Supreme Court held that so
long as a water is susceptible to use as a highway of commerce, it
is navigable-in-fact, even if the water has never been used for any
commercial purpose. U.S. v. Utah, at 81-83 (``The question of that
susceptibility in the ordinary condition of the rivers, rather than
of the mere manner or extent of actual use, is the crucial
question.''); U.S. v. Appalachian Elec. Power Co., 311 U.S. at 416
(``Nor is lack of commercial traffic a bar to a conclusion of
navigability where personal or private use by boats demonstrates the
availability of the stream for the simpler types of commercial
navigation.'') Appalachian Power further held that a water is
navigable-in-fact even if it is not navigable and never has been but
may become so by reasonable improvements. 311 U.S. at 407-08.
    In 1971, in Utah v. United States, 403 U.S. 9 (1971), the
Supreme Court held that the Great Salt Lake, an intrastate water
body, was navigable under Federal law even though it ``is not part
of a navigable interstate or international commercial highway.'' Id.
at 10. In doing so, the Supreme Court stated that the fact that the
Lake was used for hauling of animals by ranchers rather than for the
transportation of ``water-borne freight'' was an ``irrelevant
detail.'' Id. at 11. ``The lake was used as a highway and that is
the gist of the federal test.'' Id.
    Most recently, the Supreme Court explained:

The Daniel Ball formulation has been invoked in considering the
navigability of waters for purposes of assessing federal regulatory
authority under the Constitution, and the application of specific
federal statutes, as to the waters and their beds. See, e.g., ibid.;
The Montello, 20 Wall. 430, 439, 22 L.Ed. 391 (1874); United States
v. Appalachian Elec. Power Co., 311 U.S. 377, 406, and n. 21, 61
S.Ct. 291, 85 L.Ed. 243 (1940) (Federal Power Act); Rapanos v.
United States, 547 U.S. 715, 730-731, 126 S.Ct. 2208, 165 L.Ed.2d
159 (2006) (plurality opinion) (Clean Water Act); id., at 761, 126
S.Ct. 2208 (KENNEDY, J., concurring in judgment) (same). It has been
used as well to determine questions of title to water beds under the
equal-footing doctrine. See Utah, supra, at 76, 51 S.Ct. 438;
Oklahoma v. Texas, 258 U.S. 574, 586, 42 S.Ct. 406, 66 L.Ed. 771
(1922); Holt State Bank, supra, at 56, 46 S.Ct. 197. It should be
noted, however, that the test for navigability is not applied in the
same way in these distinct types of cases.

Among the differences in application are the following. For state
title under the equal-footing doctrine, navigability is determined
at the time of statehood, see Utah, supra, at 75, 51 S.Ct. 438, and
based on the ``natural and ordinary condition'' of the water, see
Oklahoma, supra, at 591, 42 S.Ct. 406. In contrast, admiralty
jurisdiction extends to water routes made navigable even if not
formerly so, see, e.g., Ex parte Boyer, 109 U.S. 629, 631-632, 3
S.Ct. 434, 27 L.Ed. 1056 (1884) (artificial canal); and federal
regulatory authority encompasses waters that only recently have
become navigable, see, e.g., Philadelphia Co. v. Stimson, 223 U.S.
605, 634-635, 32 S.Ct. 340, 56 L.Ed. 570 (1912), were once navigable
but are no longer, see Economy Light & Power Co. v. United States,
256 U.S. 113, 123-124, 41 S.Ct. 409, 65 L.Ed. 847 (1921), or are not
navigable and never have been but may become so by reasonable
improvements, see Appalachian Elec. Power Co., supra, at 407-408, 61
S.Ct. 291. With respect to the federal commerce power, the inquiry
regarding navigation historically focused on interstate commerce.
See The Daniel Ball, 1229*1229 supra, at 564. And, of course, the
commerce power extends beyond navigation. See Kaiser Aetna v. United
States, 444 U.S. 164, 173-174, 100 S.Ct. 383, 62 L.Ed.2d 332 (1979).
In contrast, for title purposes, the inquiry depends only on
navigation and not on interstate travel. See Utah, supra, at 76, 51
S.Ct. 438. This list of differences is not exhaustive. Indeed,
``[e]ach application of [the Daniel Ball] test . . . is apt to
uncover variations and refinements which require further
elaboration.'' Appalachian Elec. Power Co., supra, at 406, 61 S.Ct.
291.

PPL Montana v. Montana, 565 U.S. ------(2012).
    Also of note are two decisions from the courts of appeals. In
FPL Energy Marine Hydro, a case involving the Federal Power Act, the
D.C. Circuit reiterated the fact that ``actual use is not necessary
for a navigability determination'' and repeated earlier Supreme
Court holdings that navigability and capacity of a water to carry
commerce could be shown through ``physical characteristics and
experimentation.'' FPL Energy Marine Hydro LLC v. FERC, 287 F.3d
1151, 1157 (D.C. Cir. 2002). In that case, the D.C. Circuit upheld a
FERC navigability determination that was based upon three
experimental canoe trips taken specifically to demonstrate the
river's navigability. Id. at 1158-59.
    The 9th Circuit has also implemented the Supreme Court's holding
that a water need only be susceptible to being used for waterborne
commerce to be navigable-in-fact. Alaska v. Ahtna, Inc., 891 F.2d
1404 (9th Cir. 1989). In Ahtna, the 9th Circuit held that current
use of an Alaskan river for commercial recreational boating was
sufficient evidence of the water's capacity to carry waterborne
commerce at the time that Alaska became a state. Id. at 1405. It was
found to be irrelevant whether or not the river was actually being
navigated or being used for commerce at the time, because current
navigation showed that the river always had the capacity to support
such navigation. Id. at 1404.
    In summary, when determining whether a water body qualifies as a
``traditional navigable water'' (i.e., an (a)(1) water), relevant
considerations include whether the water body meets any of the tests
set forth in Part 329, or a Federal court has determined that the
water body is

``navigable-in-fact'' under Federal law for any purpose, or the
water body is ``navigable-in-fact'' under the standards that have
been used by the Federal courts.

Interstate Waters

1. Interstate Waters

    The agencies' proposal today makes no change to the interstate
waters section of the existing regulations and the agencies would
continue to assert jurisdiction over interstate waters, including
interstate wetlands. The language of the CWA is clear that Congress
intended the term ``navigable waters'' to include interstate waters,
and the agencies' interpretation, promulgated contemporaneously with
the passage of the CWA, is consistent with the statute and
legislative history. The Supreme Court's decisions in SWANCC and
Rapanos did not address the interstate waters provision of the
existing regulation.

A. The Language of the Clean Water Act, the Statute as a Whole, and the
Statutory History Demonstrate Congress' Clear Intent To Include
Interstate Waters as ``Navigable Waters'' Subject to the Clean Water
Act

    While as a general matter, the scope of the terms ``navigable
waters'' and ``waters of the United States'' is ambiguous, the
language of the CWA, particularly when read as a whole, demonstrates
that Congress clearly intended to continue to subject interstate
waters to Federal regulation. The statutory history of Federal water
pollution control places the terms of the CWA in context and
provides further evidence of Congressional intent to include
interstate waters within the scope of the ``navigable waters''
protected by the Act. Congress clearly intended to subject
interstate waters to CWA jurisdiction without imposing a requirement
that they be water that is navigable for purposes of Federal
regulation under the Commerce Clause themselves or be connected to
water that is navigable for purposes of Federal regulation under the
Commerce Clause.\10\ The CWA itself is clear that interstate waters
that were previously subject to Federal regulation remain subject to
Federal regulation. The text of the CWA, specifically the CWA's
provision with respect to interstate waters and their water quality
standards, in conjunction with the definition of navigable waters,
provides clear indication of Congress' intent. Thus, interstate
waters are ``navigable waters'' protected by the CWA.
---------------------------------------------------------------------------

    \10\ For purposes of the CWA, EPA and the Corps have interpreted
the term ``traditional navigable waters'' to include all of the
``navigable waters of the United States,'' defined in 33 CFR part
329 and by numerous decisions of the Federal courts, plus all other
waters that are navigable-in-fact (e.g., the Great Salt Lake, UT and
Lake Minnetonka, MN). This section explains why EPA and the Corps do
not interpret the CWA or the Supreme Court's decisions in Solid
Waste Agency of Northern Cook County (SWANCC) v. U.S. Army Corps of
Engineers, 531 U.S. 159 (2001) and Rapanos v. United States, 547
U.S. 715 (2006), to restrict CWA jurisdiction over interstate waters
to only those interstate waters that are traditional navigable
waters or that connect to traditional navigable waters.
---------------------------------------------------------------------------

(1) The Plain Language of the Clean Water Act and the Statute as a
Whole Clearly Indicate Congress' Intent to Include Interstate Waters
Within the Scope of ``Navigable Waters'' for Purposes of the Clean
Water Act

    Under well settled principles, the phrase ``navigable waters''
should not be read in isolation from the remainder of the statute.
As the Supreme Court has explained:

The definition of words in isolation, however, is not necessarily
controlling in statutory construction. A word in a statute may or
may not extend to the outer limits of its definitional
possibilities. Interpretation of a word or phrase depends upon
reading the whole statutory text, considering the purpose and
context of the statute, and consulting any precedents or authorities
that inform the analysis.

Dolan v. U.S. Postal Service, 546 U.S. 481, 486 (2006); see also
United States Nat'l. Bank of Oregon v. Indep. Ins. Agents of Am.,
Inc., 508 U.S. 439, 455 (1993).
    While the term ``navigable waters'' is, in general, ambiguous,
interstate waters are waters that are clearly covered by the plain
language of the definition of ``navigable waters.'' \11\ Congress
defined ``navigable waters'' to mean ``the waters of the United
States, including the territorial seas.'' Interstate waters are
waters of the several States and, thus, the United States. While the
1972 Act was clearly not limited to interstate waters, it was
clearly intended to include interstate waters.
---------------------------------------------------------------------------

    \11\ The Supreme Court has found that the term ``waters of the
United States'' is ambiguous in some respects. Rapanos, 547 U.S. at
752 (plurality opinion), 804 (dissent).
---------------------------------------------------------------------------

    Furthermore, the CWA does not simply define ``navigable
waters.'' Other provisions of the statute provide additional textual
evidence of the scope of this term of the Act. Most importantly,
there is a specific provision in the 1972 CWA establishing
requirements for those interstate waters which were subject to the
prior Water Pollution Control Acts.
    The CWA requires states to establish water quality standards for
navigable waters and submit them to the Administrator for
review.\12\ Under section 303(a) of the Act, in order to carry out
the purpose of this Act, any water quality standard applicable to
interstate waters which was adopted by any State and submitted to,
and approved by, or is awaiting approval by, the Administrator
pursuant to this Act as in effect immediately prior to the date of
enactment of the Federal Water Pollution Control Act Amendments of
1972, shall remain in effect unless the Administrator determined
that such standard is not consistent with the applicable
requirements of the Act as in effect immediately prior to the date
of enactment of the Federal Water Pollution Control Act Amendments
of 1972. If the Administrator makes such a determination he shall,
within three months after the date of enactment of the Federal Water
Pollution Control Act Amendments of 1972, notify the State and
specify the changes needed to meet such requirements. If such
changes are not adopted by the State within ninety days after the
date of such notification, the Administrator shall promulgate such
changes in accordance with subsection (b). CWA section 303(a)(1)
(emphasis added).
---------------------------------------------------------------------------

    \12\ Section 303 of the Act requires the states to submit
revised and new water quality standards to the Administrator for
review. CWA section 303(c)(2)(A). Such revised or new water quality
standards ``shall consist of the designated uses of the navigable
waters involved and the water quality criteria for such waters.''
Id. If the Administrator determines that a revised or new standard
is not consistent with the Act's requirements, or determines that a
revised or new standard is necessary to meet the Act's requirements,
and the state does not make required changes, ``[t]he Administrator
shall promptly prepare and publish proposed regulations setting
forth a revised or new water quality standard for the navigable
waters involved.'' CWA section 303(c)(4).
---------------------------------------------------------------------------

    Under the 1965 Act, as discussed in more detail below, states
were directed to develop water quality standards establishing water
quality goals for interstate waters. By the early 1970s, all the
states had adopted such water quality standards. Advanced Notice of
Proposed Rulemaking, Water Quality Standards Regulation, 63 FR
36742, 36745, July 7, 1998. In section 303(a), Congress clearly
intended for existing Federal regulation of interstate waters to
continue under the amended CWA. Water quality standards for
interstate waters were not merely to remain in effect, but EPA was
required to actively assess those water quality standards and even
promulgate revised standards for interstate waters if states did not
make necessary changes. By the plain language of the statute, these
water quality standards for interstate waters were to remain in
effect ``in order to carry out the purpose of this Act.'' The
objective of the Act is ``to restore and maintain the chemical,
physical, and biological integrity of the Nation's waters.'' CWA
section 101(a). It would contravene Congress' clearly stated intent
for a court to impose an additional jurisdictional requirement on
all rivers, lakes, and other waters that flow across, or form a part
of, state boundaries (``interstate waters'' as defined by the 1948
Act, Sec.  10, 62 Stat. 1161), such that interstate waters that were
previously protected were no longer protected because they lacked a
connection to a water that is navigable for purposes of Federal
regulation under the Commerce Clause. Nor would all the existing
water quality standards be ``carry[ing] out the purpose of this
Act,'' if the only water quality standards that could be implemented
through the Act (through, for example, National Pollutant Discharge
Elimination System permits under section 402) were those water
quality standards established for interstate waters that are also
waters that are navigable for purposes of Federal regulation under
the Commerce Clause or that connect to waters that are navigable for
purposes of Federal regulation under the Commerce Clause. Nowhere in
section 303(a) does Congress make such a distinction.

(2) The Federal Water Pollution Control Statute That Became the Clean
Water Act Covered Interstate Waters

    In 1972, when Congress rewrote the law governing water
pollution, two Federal statutes addressed discharges of pollutants
into interstate waters and water that is

navigable for purposes of Federal regulation under the Commerce
Clause, and tributaries of each: The Water Pollution Control Act of
1948, as amended, and section 13 of the Rivers and Harbors Act of
1899 (known as the ``Refuse Act''). Of the two, the Water Pollution
Control Act extended Federal authority over interstate waters and
their tributaries. In contrast, the Refuse Act extended Federal
jurisdiction over the ``navigable waters of the United States'' and
their tributaries. These two separate statutes demonstrate that
Congress recognized that interstate waters and ``navigable waters of
the United States'' were independent lawful bases of Federal
jurisdiction.

a. The Federal Water Pollution Control Act Prior to 1972

    From the outset, and through all the amendments pre-dating the
1972 Amendments, the Federal authority to abate water pollution
under the Water Pollution Control Act, and the Federal Water
Pollution Control Act (FWPCA) as it was renamed in 1956, extended to
interstate waters. In addition, since first enacted in 1948, and
throughout all the amendments, the goals of the Act have been, inter
alia, to protect public water supplies, propagation of fish and
aquatic life, recreation, agricultural, industrial, and other
legitimate uses. See 62 Stat. 1155 and 33 U.S.C. 466 (1952), 33
U.S.C. 466 (1958), 33 U.S.C. 466 (1964), 33 U.S.C. 1151 (1970).
    In 1948, Congress enacted the Water Pollution Control Act in
connection with the exercise of jurisdiction over the waterways of
the Nation and in the consequence of the benefits to public health
and welfare by the abatement of stream pollution. See Pub. L. No.
80-845, 62 Stat. 1155 (June 30, 1948). The Act authorized technical
assistance and financial aid to states for stream pollution
abatement programs, and made discharges of pollutants into
interstate waters and their tributaries a nuisance, subject to
abatement and prosecution by the United States. See section
2(d)(1),(4), 62 Stat. at 1156-1157 (section 2(d)(1) of the Water
Pollution Control Act of 1948, 62 Stat. at 1156, stated that the
``pollution of interstate waters'' in or adjacent to any State or
States (whether the matter causing or contributing to such pollution
is discharged directly into such waters or reaches such waters after
discharge into a tributary of such waters), which endangers the
health or welfare of persons in a State other than that in which the
discharge originates, is declared to be a public nuisance and
subject to abatement as provided by the Act. (emphasis added));
Sec.  2(a), 62 Stat. 1155 (requiring comprehensive programs for
``interstate waters and tributaries thereof''); Sec.  5, 62 Stat.
1158 (authorizing loans for sewage treatment to abate discharges
into ``interstate waters or into a tributary of such waters'').
Under the statute, ``interstate waters'' were defined as all rivers,
lakes, and other waters that flow across, or form a part of, state
boundaries. Section 10, 62 Stat. 1161.
    In 1956, Congress strengthened measures for controlling
pollution of interstate waters and their tributaries. Public Law 84-
660, 70 Stat. 498 (1956) (directing further cooperation between the
Federal and State Governments in development of comprehensive
programs for eliminating or reducing ``the pollution of interstate
waters and tributaries'' and improving the sanitary condition of
surface and underground waters, and authorizing the Surgeon General
to make joint investigations with States into the conditions of and
discharges into ``any waters of any State or States.'').
    In 1961, Congress amended the FWPCA to substitute the term
``interstate or navigable waters'' for ``interstate waters.'' See
Public Law 87-88, 75 Stat. 208 (1961). Accordingly, beginning in
1961, the provisions of the FWPCA applied to all interstate waters
and navigable waters and the tributaries of each, see 33 U.S.C.
466a, 466g(a) (1964).\13\
---------------------------------------------------------------------------

    \13\ Congress did not define the term ``navigable waters'' in
the 1961 Amendments, or in subsequent FWPCA Amendments, until 1972.
---------------------------------------------------------------------------

    In 1965, Congress approved a second set of major legislative
changes, requiring each state to develop water quality standards for
interstate waters within its boundaries by 1967. Public Law 89-234,
79 Stat. 908 (1965).\14\ Failing establishment of adequate standards
by the state, the Act authorized establishment of water quality
standards by Federal regulation. Id. at 908. The 1965 Amendments
provided that the discharge of matter ``into such interstate waters
or portions thereof,'' which reduces the quality of such waters
below the water quality standards established under this subsection
(whether the matter causing or contributing to such reduction is
discharged directly into such waters or reaches such waters after
discharge into tributaries of such waters), is subject to abatement
through procedures specified in the Act, including (after
conferences and negotiations and consideration by a Hearing Board)
legal action in the courts. Id. at 909.\15\
---------------------------------------------------------------------------

    \14\ In 1967, the state of Arizona created the Water Quality
Control Council (Council) to implement the requirements of the 1965
FWPCA. The Council adopted water quality standards for those waters
that were considered ``interstate waters'' pursuant to the existing
Federal law. The Council identified the Santa Cruz River as an
interstate water and promulgated water quality standards for the
river in accordance with Federal law.
    \15\ The 1966 Amendments authorized civil fines for failing to
provide information about an alleged discharge causing or
contributing to water pollution. Public Law 89-753, 80 Stat. 1250
(1966); see also S. Rep. No. 414, 92d Congress, 1st Sess. 10 (1972)
(describing the history of the FWPCA).
---------------------------------------------------------------------------

 b. The Refuse Act

    Since its original enactment in 1899, the Refuse Act has
prohibited the discharge of refuse matter ``into any navigable water
of the United States, or into any tributary of any navigable
water.'' Ch. 425, 30 Stat. 1152 (1899). It also has prohibited the
discharge of such material on the bank of any tributary where it is
liable to be washed into a navigable water. Id. Violators are
subject to fines and imprisonment. Id. at 1153 (codified at 33
U.S.C. 412). In 1966, the Supreme Court upheld the Corps'
interpretation of the Refuse Act as prohibiting discharges that
pollute the navigable waters, and not just those discharges that
obstruct navigation. United States v. Standard Oil Co., 384 U.S.
224, 230 (1966). In 1970, President Nixon signed an Executive Order
directing the Corps (in consultation with the Federal Water
Pollution Control Administration \16\) to implement a permit program
under section 13 of the RHA ``to regulate the discharge of
pollutants and other refuse matter into the navigable waters of the
United States or their tributaries and the placing of such matter
upon their banks.'' E.O. 11574, 35 FR 19627, Dec. 25, 1970. In 1971,
the Corps promulgated regulations establishing the Refuse Act Permit
Program. 36 FR 6564, 6565, April 7, 1971. The regulations made it
unlawful to discharge any pollutant (except those flowing from
streets and sewers in a liquid state) into a navigable waterway or
tributary, except pursuant to a permit. Under the permit program,
EPA advised the Corps regarding the consistency of a proposed
discharge with water quality standards and considerations, and the
Corps evaluated a permit application for impacts on anchorage,
navigation, and fish and wildlife resources. Id. at 6566.
---------------------------------------------------------------------------

    \16\ In December 1970, administration of the Federal Water
Pollution Control Administration was transferred from the Secretary
of the Interior to EPA. S. Rep. No. 414, 92d Congress, 1st Sess.
(1972).
---------------------------------------------------------------------------

 c. The Federal Water Pollution Control Act Amendments of 1972

    When Congress passed the Federal Water Pollution Control Act
Amendments of 1972 (referred to hereinafter as the CWA or CWA), it
was not acting on a blank slate. It was amending existing law that
provided for a Federal/State program to address water pollution. The
Supreme Court has recognized that Congress, in enacting the CWA in
1972, ``intended to repudiate limits that had been placed on federal
regulation by earlier water pollution control statutes and to
exercise its powers under the Commerce Clause to regulate at least
some waters that would not be deemed `navigable' under the classical
understanding of that term.'' Riverside Bayview Homes, 474 U.S. at
133; see also International Paper Co. v. Ouellette, 479 U.S. 481,
486, n.6 (1987).
    The amendments of 1972 defined the term ``navigable waters'' to
mean ``the waters of the United States, including the territorial
seas.'' 33 U.S.C. 1362(7). While earlier versions of the 1972
legislation defined the term to mean ``the navigable waters of the
United States,'' the Conference Committee deleted the word
``navigable'' and expressed the intent to reject prior geographic
limits on the scope of Federal water-protection measures. Compare S.
Conf. Rep. No. 1236, 92d Cong., 2d Sess. 144 (1972), with H.R. Rep.
No. 911, 92 Cong., 2d Sess. 356 (1972) (bill reported by the House
Committee provided that ``[t]he term `navigable waters' means the
navigable waters of the United States, including the territorial
seas''); see also S. Rep. No. 414, 92d Cong., 1st Sess. 77
(``Through a narrow interpretation of the definition of interstate
waters the implementation of the 1965 Act was severely limited. . .
. Therefore, reference to the control requirements must be made to
the navigable waters, portions thereof, and their tributaries.'').
Thus, Congress intended the scope of the 1972 Act to include, at a

minimum, the waters already subject to Federal water pollution
control law--both interstate waters and waters that are navigable
for purposes of Federal regulation under the Commerce Clause. Those
statutes covered interstate waters, defined interstate waters
without requiring that they be a traditional navigable water or be
connected to water that is a traditional navigable water, and
demonstrated that Congress knew that there are interstate waters
that are not navigable for purposes of Federal regulation under the
Commerce Clause.
    In fact, Congress amended the Federal Water Pollution Control
Act in 1961 to substitute the term ``interstate or navigable
waters'' for ``interstate waters,'' demonstrating that Congress
wanted to be very clear that it was asserting jurisdiction over both
types of waters: interstate waters even if they were not navigable
for purposes of Federal regulation under the Commerce Clause, and
traditional navigable waters even if they were not interstate
waters. At no point were the interstate waters already subject to
Federal water pollution control authority required to be navigable
or to connect to a traditional navigable water. Further, as
discussed above, the legislative history clearly demonstrates that
Congress was expanding jurisdiction--not narrowing it--with the 1972
amendments. Thus, it is reasonable to conclude that by defining
``navigable waters'' as ``the waters of the United States'' in the
1972 amendments, Congress included not just traditionally navigable
waters, but all waters previously regulated under the Federal Water
Pollution Control Act, including non-navigable interstate waters.
    Based on the statutory definition of navigable waters, the
requirement of section 303(a) for water quality standards for
interstate waters to remain in effect, the purposes of the Act, and
the more than three decades of Federal water pollution control
regulation that provides a context for reading those provisions of
the statute, the intent of Congress is clear that the term
``navigable waters'' includes ``interstate waters'' as an
independent basis for CWA jurisdiction, whether or not they
themselves are traditional navigable waters or are connected to a
traditional navigable water.

B. Supreme Court Precedent Supports CWA Jurisdiction Over
Interstate Waters Without Respect to Navigability

    In two seminal decisions, the Supreme Court established that
resolving interstate water pollution issues was a matter of Federal
law and that the CWA was the comprehensive regulatory scheme for
addressing interstate water pollution. Illinois v. Milwaukee, 406
U.S. 91 (1972); City of Milwaukee v. Illinois, 451 U.S. 304 (1981).
In both of these decisions, the Court held that Federal law applied
to interstate waters. Moreover, these cases analyzed the applicable
Federal statutory schemes and determined that the provisions of the
Federal Water Pollution Control Act and the CWA regulating water
pollution applied generally to interstate waters. The holdings of
these cases recognized the Federal interest in interstate water
quality pollution; and City of Milwaukee recognized that CWA
jurisdiction extends to interstate waters without regard to
navigability.
    In Illinois v. Milwaukee, the Court considered a public nuisance
claim brought by the State of Illinois against the city of Milwaukee
to address the adverse effects of Milwaukee's discharges of poorly
treated sewage into Lake Michigan, ``a body of interstate water.''
406 U.S. at 93. In relevant part, the Court held that the Federal
common law of nuisance was an appropriate mechanism to resolve
disputes involving interstate water pollution. 406 U.S. at 107
(``federal courts will be empowered to appraise the equities of
suits alleging creation of a public nuisance by water pollution'').
The Court further noted that in such actions the Court could
consider a state's interest in protecting its high water quality
standards from ``the more degrading standards of a neighbor.'' Id.
    In reaching this conclusion, the Court examined in detail the
scope of the Federal regulatory scheme as it existed prior to the
October, 1972 FWPCA amendments. In its April, 1972 decision, the
Court concluded that the Federal Water Pollution Control Act ``makes
clear that it is federal, not state, law that in the end controls
the pollution of interstate or navigable waters.'' 406 U.S. at 102
(emphasis added). The Court, in this case, concluded that the
regulatory provisions of the Federal Water Pollution Control Act did
not address the right of a state to file suit to protect water
quality. However, this was not because this statute did not reach
interstate waters. The Court specifically noted that section 10(a)
of the Federal Water Pollution Control Act ``makes pollution of
interstate or navigable waters subject `to abatement' '' 406 U.S. at
102 (emphasis added). Rather, the Court noted that the plaintiff in
this action was seeking relief outside the scope of the Federal
Water Pollution Control Act and that statute explicitly provided
that independent ``state and interstate action to abate pollution of
interstate or navigable waters shall be encouraged and shall not . .
. be displaced by Federal enforcement action.'' 406 U.S. at 104
(citing section 10(b) of the Federal Water Pollution Control Act).
    In addition, in Illinois v. Milwaukee, the Court acknowledged
that it was essential for Federal law to resolve interstate water
pollution disputes, citing with approval the following discussion
from Texas v. Pankey:

Federal common law and not the varying common law of the individual
states is, we think, entitled and necessary to be recognized as a
basis for dealing in uniform standard with the environmental rights
of a State against improper impairment by sources outside its
domain. . . . Until the field has been made the subject of
comprehensive legislation or authorized administrative standards,
only a federal common law basis can provide an adequate means for
dealing with such claims as alleged federal rights.

406 U.S. at 107 n. 9, citing Texas v. Pankey, 441 F.2d 236, 241-242.
    In City of Milwaukee, the Court revisited this dispute and
addressed the expanded statutory provisions of the CWA regulating
water pollution. The scope of the CWA amendments led the Court to
reverse its decision in Illinois v. Milwaukee. In reaching this
result, the Court concluded that Congress had elected to exercise
its authority under Federal law to occupy the field of water
pollution regulation. As a result, the Court concluded that there
was no basis for maintaining a Federal common law of nuisance.

Congress has not left the formulation of appropriate federal
standards to the courts through application of often vague and
indeterminate nuisance concepts and maxims of equity jurisprudence,
but rather has occupied the field through the establishment of a
comprehensive regulatory program supervised by an expert
administrative agency. The 1972 Amendments to the Federal Water
Pollution Control Act were not merely another law ``touching
interstate waters''. . . Rather, the Amendments were viewed by
Congress as a ``total restructuring'' and ``complete rewriting'' of
the existing water pollution legislation considered in that case.

451 U.S. at 317.
    The Court's analysis in Illinois v. Milwaukee made clear that
Federal common law was necessary to protect ``the environmental
rights of States against improper impairment by sources outside its
domain.'' 406 U.S. at 107, n. 9. In the context of interstate water
pollution, nothing in the Court's language or logic limits the reach
of this conclusion to only navigable interstate waters. In City of
Milwaukee, the Court found that the CWA was the ``comprehensive
regulatory program'' that ``occupied the field'' (451 U.S. 317) with
regard to interstate water pollution, eliminating the basis for an
independent common law of nuisance to address interstate water
pollution. Since the Federal common law of nuisance (as well as the
statutory provisions regulating water pollution in the Federal Water
Pollution Control Act) applied to interstate waters whether
navigable or not, the CWA could only occupy the field of interstate
water pollution if it too extended to non-navigable as well as
navigable interstate waters.
    With regard to the specifics of interstate water pollution, the
City of Milwaukee Court noted that, in Illinois v. Milwaukee, it had
been concerned that Illinois did not have a forum in which it could
protect its interests in abating water pollution from out of state,
absent the recognition of Federal common law remedies. 451 U.S. at
325. The Court then went on to analyze in detail the specific
procedures created by the CWA ``for a State affected by decisions of
a neighboring State's permit-granting agency to seek redress.'' 451
U.S. at 326. The Court noted that ``any State whose waters may be
affected by the issuance of a permit'' is to receive notice and the
opportunity to comment on the permit. Id. (citing to CWA section
402(b)(3)(5). In addition the Court noted provisions giving EPA the
authority to veto and issue its own permits ``if a stalemate between
an issuing and objecting state develops.'' Id. (citing to CWA
sections 402(d)(2)(A),(4)). In light of these protections for states
affected by interstate water pollution, the court concluded that

[t]he statutory scheme established by Congress provides a forum for
the pursuit of such claims before expert agencies by means of the
permit-granting process. It would be quite inconsistent with this
scheme if federal courts were in effect to ``write their own
ticket'' under the guise of federal common law after permits have
already been issued and permittees have been planning and operating
in reliance on them.

451 U.S. at 326.

    Nothing in the language or the reasoning of this discussion
limits the applicability of these protections of interstate waters
to navigable interstate waters or interstate waters connected to
navigable waters. If these protections only applied to navigable
interstate waters, a downstream state would be unable to protect
many of its waters from out of state water pollution. This would
hardly constitute a comprehensive regulatory scheme that occupied
the field of interstate water pollution.
    For these reasons, the holdings and the reasoning of these
decisions establish that the regulatory reach of the CWA extends to
all interstate waters without regard to navigability.\17\
---------------------------------------------------------------------------

    \17\ Nothing in subsequent Supreme Court case law regarding
interstate waters in any way conflicts with the agencies'
interpretation. See International Paper v. Ouellette, 479 U.S. 481
(1987); Arkansas v. Oklahoma, 503 U.S. 91 (1992). In both of these
cases, the Court detailed how the CWA had supplanted the Federal
common law of nuisance to establish the controlling statutory scheme
for addressing interstate water pollution disputes. Nothing in
either decision limits the applicability of the CWA to interstate
water pollution disputes involving navigable interstate waters or
interstate waters connected to navigable waters.
---------------------------------------------------------------------------

C. The Supreme Court's Decisions in SWANCC and Rapanos Do Not Limit
or Constrain Clean Water Act Jurisdiction Over Non-Navigable
Interstate Waters

    As noted above, the Supreme Court recognized that Congress, in
enacting the CWA, ``intended to repudiate limits that had been
placed on federal regulation by earlier water pollution control
statutes and to exercise its powers under the Commerce Clause to
regulate at least some waters that would not be deemed `navigable'
under the classical understanding of that term.'' Riverside Bayview,
474 U.S. at 133; see also International Paper Co. v. Ouellette, 479
U.S. 481, 486 n.6, (1987). In Riverside Bayview, and subsequently in
SWANCC and Rapanos, the Court addressed the construction of the CWA
terms ``navigable waters'' and ``the waters of the United States.''
In none of these cases did the Supreme Court address interstate
waters, nor did it overrule prior Supreme Court precedent which
addressed the interaction between the CWA and Federal common law to
address pollution of interstate waters. Therefore, the statute, even
in light of SWANCC and Rapanos, does not impose an additional
requirement that interstate waters must be water that is navigable
for purposes of Federal regulation under the Commerce Clause or
connected to water that is navigable for purposes of Federal
regulation under the Commerce Clause to be jurisdictional waters for
purposes of the CWA.
    At the outset, it is worth noting that neither SWANCC nor
Rapanos dealt with the jurisdictional status of interstate waters.
Repeatedly in the SWANCC decision the Court emphasized that the
question presented concerned the jurisdiction status of nonnavigable
intrastate waters located in two Illinois counties. SWANCC 531 U.S.
at 165-166, 171 (``we thus decline to . . . hold that isolated
ponds, some only seasonal, wholly located within two Illinois
counties fall under Sec.  404(a) definition of navigable waters . .
.'') (emphasis added). Nowhere in Justice Rehnquist's majority
opinion in SWANCC does the Court discuss the Court's interstate
water case law.\18\ The Court does not even discuss the fact that
CWA jurisdictional regulations identify interstate waters as
regulated ``waters of the United States.'' In fact, the repeated
emphasis on the intrastate nature of the waters at issue can be read
as an attempt to distinguish SWANCC from the Court's interstate
water jurisprudence.
---------------------------------------------------------------------------

    \18\ It is worth noting the Justice Rehnquist was also the
author of City of Milwaukee.
---------------------------------------------------------------------------

    In Rapanos, the properties at issue were located entirely within
the State of Michigan. 547 U.S. 715, 762-764. Thus, the Court had no
occasion to address the text of the CWA with respect to interstate
waters or the agencies' regulatory provisions concerning interstate
waters. In addition, neither Justice Kennedy nor the plurality
discusses the impact of their opinions on the Court's interstate
waters jurisprudence. The plurality decision acknowledges that CWA
jurisdictional regulations include interstate waters. 547 U.S. 715,
724. However, the plurality did not discuss in any detail its views
as to the continued vitality of regulations concerning such waters.
    Moreover, one of the analytical underpinnings of the SWANCC and
Rapanos decisions is irrelevant to analysis of regulations asserting
jurisdiction over interstate waters. In SWANCC, the Court declined
to defer to agency regulations asserting jurisdiction over isolated
waters because

[w]here an administrative interpretation of a statute invokes the
outer limits of Congress' power, we expect a clear indication that
Congress intended that result. . . .This requirement stems from our
prudential desire not to needlessly reach constitutional issues and
our assumption that Congress does not casually authorize
administrative agencies to interpret a statute to push the limit of
Congressional authority. . . . This concern is heightened where the
administrative interpretation alerts the federal-state framework by
permitting federal encroachment upon a traditional state power.

531 U.S. at 172-173 (citations omitted).
    However, the Court's analysis in Illinois v. Milwaukee and City
of Milwaukee makes clear that Congress has broad authority to create
Federal law to resolve interstate water pollution disputes. As
discussed above, the Court in Illinois v. Milwaukee, invited further
Federal legislation to address interstate water pollution, and in so
doing concluded that State law was not an appropriate basis for
addressing interstate water pollution issues. 406 U.S. at 107 n. 9
(citing Texas v. Pankey, 441 F.2d 236, 241-242). In City of
Milwaukee, the Court indicated that central to its holding in
Illinois v. Milwaukee was its concern ``that Illinois did not have
any forum to protect its interests [in the matters involving
interstate water pollution].'' 451 U.S. 325. As discussed above, the
Court cited with approval the statutory provisions of the CWA
regulating water pollution as an appropriate means to address that
concern.
    The City of Milwaukee and Illinois v. Milwaukee decisions make
clear that assertion of Federal authority to resolve disputes
involving interstate waters does not alter ``the Federal-State
framework by permitting Federal encroachment on a traditional State
power.'' 531 U.S. at 173. ``Our decisions concerning interstate
waters contain the same theme. Rights in interstate streams, like
questions of boundaries, have been recognized as presenting Federal
questions.'' Illinois v. Milwaukee, 406 U.S. at 105 (internal
quotations and citations omitted).
    The Supreme Court's analysis in SWANCC and Rapanos materially
altered the criteria for analyzing CWA jurisdictional issues for
wholly intrastate waters. However, these decisions by their terms
did not affect the body of case law developed to address interstate
waters. The holdings in the Supreme Court's interstate waters
jurisprudence, in particular City of Milwaukee, apply CWA
jurisdiction to interstate waters without regard to, or discussion
of, navigability. In City of Milwaukee, the Court held that the CWA
provided a comprehensive statutory scheme for addressing the
consequences of interstate water pollution. Based on this analysis,
the Court expressly overruled its holding in Illinois v. Milwaukee
that the Federal common law of nuisance would apply to resolving
interstate water pollution disputes. Instead, the Court held that
such disputes would now be resolved through application of the
statutory provisions of the CWA regulating water pollution.
    It would be unreasonable to interpret SWANCC or Rapanos as
overruling City of Milwaukee with respect to CWA jurisdiction over
non-navigable interstate waters. Such an interpretation would result
in no law to apply to water pollution disputes with regard to such
waters, unless one were to assume that the Court intended (without
discussion or analysis) to restore the Federal common law of
nuisance as the law to apply in such matters. Moreover, SWANCC and
Rapanos acknowledge that CWA regulatory jurisdiction extends to at
least some non-navigable waters. See, e.g., 547 U.S. at 779
(Kennedy, J.). Neither the SWANCC Court nor the plurality or Kennedy
opinions in Rapanos purports to set out the complete boundaries of
CWA jurisdiction. See, e.g., 547 U.S. at 731 (``[w]e need not decide
the precise extent to which the qualifiers `navigable' and `of the
United States' restrict the coverage of the Act.'') (plurality
opinion).
    In addition, as the Supreme Court has repeatedly admonished, if
a Supreme Court precedent has direct application in a case yet
appears to rest on a rationale rejected in some other line of
decisions, lower courts should follow the case which directly
controls,

leaving to the Supreme Court the prerogative of overruling its
precedents. Agostino v. Felton, 521 U.S. 203, 237 (1997); United
States v. Hatter, 532 U.S. 557, 566-567 (1981). Moreover, when the
Supreme Court overturns established precedent, it is explicit. See,
Lawrence v. Texas, 539 U.S. 558, 578 (``Bowers was not correct when
it was decided, and it is not correct today. It ought not to remain
binding precedent. Bowers v. Hardwick should be and now is
overruled.'').

D. The Agencies' Longstanding Interpretation of the Term
``Navigable Waters'' To Include ``Interstate Waters''

    EPA, the agency charged with implementing the CWA, has always
interpreted the 1972 Act to cover interstate waters. Final Rules, 38
FR 13528, May 22, 1973 (the term ``waters of the United States''
includes ``interstate waters and their tributaries, including
adjacent wetlands''). While the Corps of Engineers initially limited
the scope of coverage for purposes of section 404 of the CWA to
those waters that were subject to the Rivers and Harbors Act of
1899, after a lawsuit, the Corps amended its regulations to provide
for the same definition of ``waters of the United States'' that
EPA's regulations had always established. In 1975, the Corps'
revised regulations defined ``navigable waters'' to include
``[i]nterstate waters landward to their ordinary high water mark and
up to their headwaters.'' In their final rules promulgated in 1977,
the Corps adopted EPA's definition and included within the
definition of ``waters of the United States'' ``interstate waters
and their tributaries, including adjacent wetlands.'' The preamble
provided an explanation for the inclusion of interstate waters:

The affects [sic] of water pollution in one state can adversely
affect the quality of the waters in another, particularly if the
waters involved are interstate. Prior to the FWPCA amendments of
1972, most federal statutes pertaining to water quality were limited
to interstate waters. We have, therefore, included this third
category consistent with the Federal government's traditional role
to protect these waters from the standpoint of water quality and the
obvious effects on interstate commerce that will occur through
pollution of interstate waters and their tributaries.

Final Rules, 42 FR 37122, July 19, 1977.

    The legislative history similarly provides support for the
agencies' interpretation. Congress in 1972 concluded that the
mechanism for controlling discharges and, thereby abating pollution,
under the FWPCA and Refuse Act ``has been inadequate in every vital
aspect.'' S. Rep. No. 414, 92d Cong., 1st Sess. 7 (1972). The Senate
Committee on Public Works reported that development of water quality
standards, assigned to the states under the 1965 FWPCA Amendments,
``is lagging'' and the ``1948 abatement procedures, and the almost
total lack of enforcement,'' prompted the search for ``more direct
avenues of action against water polluters and water pollution.'' Id.
at 5. The Committee further concluded that although the Refuse Act
permit program created in 1970 ``seeks to establish this direct
approach,'' it was too weak because it applied only to industrial
polluters and too unwieldy because the authority over each permit
application was divided between two Federal agencies. See id. at 5;
see also id. at 70-72 (discussing inadequacies of Refuse Act
program).
    In light of the poor success of those programs, the Committee
recommended a more direct and comprehensive approach which, after
amendment in conference, was adopted in the 1972 Act. The text,
legislative history and purpose of the 1972 Amendments all show an
intent--through the revisions--to broaden, improve and strengthen,
not to curtail, the Federal water pollution control program that had
existed under the Refuse Act and FWPCA.\19\ The 1972 FWPCA
Amendments were ``not merely another law `touching interstate
waters' '' but were ``viewed by Congress as a `total restructuring'
and `complete rewriting' of the existing water pollution
legislation.'' \20\
---------------------------------------------------------------------------

    \19\ See id. at 9 (``The scope of the 1899 Refuse Act is
broadened; the administrative capability is strengthened.''); id. at
43 (``Much of the Committee's time devoted to this Act centered on
an effort to resolve the existing water quality program and the
separate pollution program developing under the 1899 Refuse Act.'').
Congress made an effort ``to weave'' the Refuse Act permit program
into the 1972 Amendments, id. at 71, as the statutory text shows.
See 33 U.S.C. 1342(a) (providing that each application for a permit
under 33 U.S.C. 407, pending on October 18, 1972, shall be deemed an
application for a permit under 33 U.S.C. 1342(a)).
    \20\ City of Milwaukee v. Illinois, 451 U.S. at 317; see also
id. at 318 (holding that the CWA precluded Federal common-law claims
because ``Congress' intent in enacting the [CWA] was clearly to
establish an all-encompassing program of water pollution
regulation''); Middlesex County Sewerage Auth. v. National Sea
Clammers Ass'n, 453 U.S. 1, 22 (1981) (existing statutory scheme
``was completely revised'' by enactment of the CWA).
---------------------------------------------------------------------------

    As the legislative history of the 1972 Act confirms, Congress'
use of the term ``waters of the United States'' was intended to
repudiate earlier limits on the reach of Federal water pollution
efforts: ``The conferees fully intend that the term `navigable
waters' be given the broadest possible constitutional interpretation
unencumbered by agency determinations which have been made or may be
made for administrative purposes.'' See S. Conf. Rep. No. 1236, 92d
Cong., 2d Sess. 144 (1972). The House and Senate Committee Reports
further elucidate the Conference Committee's rationale for removing
the word ``navigable'' from the definition of ``navigable waters,''
in 33 U.S.C. 1362(7). The Senate report stated:

    The control strategy of the Act extends to navigable waters. The
definition of this term means the navigable waters of the United
States, portions thereof, tributaries thereof, and includes the
territorial seas and the Great Lakes. Through a narrow
interpretation of the definition of interstate waters the
implementation of the 1965 Act was severely limited. Water moves in
hydrologic cycles and it is essential that discharge of pollutants
be controlled at the source. Therefore, reference to the control
requirements must be made the navigable waters, portions thereof,
and their tributaries.

See S. Rep. 414, 92d Cong., 1st Sess. 77 (1971); see also H.R. Rep.
No. 911, 92d Cong., 2d Sess. 131 (1972) (``The Committee fully
intends that the term ``navigable waters'' be given the broadest
possible constitutional interpretation unencumbered by agency
determinations which have been made or may be made for
administrative purposes.''). These passages strongly suggest that
Congress intended to expand Federal protection of waters. There is
no evidence that Congress intended to exclude interstate waters
which were protected under Federal law if they were not water that
is navigable for purposes of Federal regulation under the Commerce
Clause or connected to water that is navigable for purposes of
Federal regulation under the Commerce Clause. Such an exclusion
would be contrary to all the stated goals of Congress in enacting
the sweeping amendments which became the CWA.
    The CWA was enacted in 1972. EPA's contemporaneous regulatory
definition of ``waters of the United States,'' promulgated in 1973,
included interstate waters. The definition has been EPA's
interpretation of the geographic jurisdictional scope of the CWA for
approximately 40 years. Congress has also been aware of and has
supported the Agency's longstanding interpretation of the CWA.
``Where `an agency's statutory construction has been fully brought
to the attention of the public and the Congress, and the latter has
not sought to alter that interpretation although it has amended the
statute in other respects, then presumably the legislative intent
has been correctly discerned.' '' North Haven Board of Education v.
Bell, 102 456 U.S. 512, 535 (1982) (quoting United States v.
Rutherford, 442 U.S. 544 n. 10 (1979) (internal quotes omitted)).
    The 1977 amendments to the CWA were the result of Congress'
thorough analysis of the scope of CWA jurisdiction in light of EPA
and Corps regulations. The 1975 interim final regulations
promulgated by the Corps in response to NRDC v. Callaway,\21\
aroused considerable congressional interest. Hearings on the subject
of section 404 jurisdiction were held in both the House and the
Senate.\22\ An amendment to limit the geographic reach of section
404 to waters that are navigable for purposes of Federal regulation
under the Commerce Clauses and their adjacent wetlands was passed by
the House, 123 Cong. Rec. 10434 (1977), defeated on the floor of the
Senate, 123 Cong. Rec. 26728 (1977), and eliminated by the
Conference Committee, H.R. Conf. Rep. 95-830, 95th Cong., 1st Sess.
97-105 (1977). Congress rejected the proposal to limit the
geographic reach of section 404 because it wanted a permit system
with ``no gaps'' in its protective sweep. 123 Cong. Rec. 26707
(1977) (remarks of Sen. Randolph). Rather than alter the geographic
reach of section

404, Congress amended the statute by exempting certain activities--
most notably certain agricultural and silvicultural activities--from
the permit requirements of section 404. See 33 U.S.C. 1344(f).
---------------------------------------------------------------------------

    \21\ 40 FR 31320, 31324 (July 25, 1975).
    \22\ Section 404 of the Federal Water Pollution Control Act
Amendments of 1972: Hearings Before the Senate Comm. on Public
Works, 94th Cong., 2d Sess. (1976); Development of New Regulations
by the Corps of Engineers, Implementing Section 404 of the Federal
Water Pollution Control Act Concerning Permits for Disposal of
Dredge or Fill Material: Hearings Before the Subcomm. on Water
Resources of the House Comm. on Public Works and Transportation,
94th Cong., 1st Sess. (1975).
---------------------------------------------------------------------------

    Other evidence abounds to support the conclusion that when
Congress rejected the attempt to limit the geographic reach of
section 404, it was well aware of the jurisdictional scope of EPA
and the Corps' definition of ``waters of the United States.'' For
example, Senator Baker stated (123 Cong. Rec. 26718 (1977)):

Interim final regulations were promulgated by the [C]orps [on] July
25, 1975.* * * Together the regulations and [EPA] guidelines
established a management program that focused the decisionmaking
process on significant threats to aquatic areas while avoiding
unnecessary regulation of minor activities. On July 19, 1977, the
[C]orps revised its regulations to further streamline the program
and correct several misunderstandings. * * *
Continuation of the comprehensive coverage of this program is
essential for the protection of the aquatic environment. The once
seemingly separable types of aquatic systems are, we now know,
interrelated and interdependent. We cannot expect to preserve the
remaining qualities of our water resources without providing
appropriate protection for the entire resource.
Earlier jurisdictional approaches under the [Rivers and Harbors Act]
established artificial and often arbitrary boundaries. . . .

    This legislative history leaves no room for doubt that Congress
was aware of the agencies' definition of navigable waters. While
there was controversy over the assertion of jurisdiction over all
adjacent wetlands and some non-adjacent wetlands, the agencies'
assertion of CWA jurisdiction over interstate waters was
uncontroversial.
    Finally, the constitutional concerns which led the Supreme Court
to decline to defer to agency regulations in SWANCC and Rapanos are
not present here where the agency is asserting jurisdiction over
interstate waters. In SWANCC, the Court declined to defer to agency
regulations asserting jurisdiction over non-adjacent, non-navigable,
intrastate waters because the Court felt such an interpretation of
the statute invoked the outer limits of Congress' power. The Court's
concern ``is heightened where the administrative interpretation
alters the federal-state framework by permitting federal
encroachment upon a traditional state power.'' 531 U.S. at 172-173
(citations omitted). Authority over interstate waters is squarely
within the bounds of Congress' Commerce Clause powers.\23\ Further,
the Federal Government is in the best position to address issues
which may arise when waters cross state boundaries, so this
interpretation does not disrupt the Federal-State framework in the
manner the Supreme Court feared that the assertion of jurisdiction
over a non-adjacent, non-navigable, intrastate body of water based
on the presence of migratory birds did. The Supreme Court's analysis
in Illinois v. Milwaukee and City of Milwaukee makes clear that
Congress has broad authority to create Federal law to resolve
interstate water pollution disputes. Therefore, as discussed in
Section II.B above, it is appropriate for the agencies to adopt an
interpretation of the extent of CWA jurisdiction over interstate
waters that gives full effect to City of Milwaukee unless and until
the Supreme Court elects to revisit its holding in that case.
---------------------------------------------------------------------------

    \23\ In Illinois v. Milwaukee, the Supreme Court noted that
``Congress has enacted numerous laws touching interstate waters.''
406 U.S. at 101.
---------------------------------------------------------------------------

    Thus, based on the language of the statute, the statutory
history, the legislative history, and the caselaw, the agencies'
continue their longstanding interpretation of ``navigable waters''
to include interstate waters.

Tributaries

    In Rapanos, Justice Kennedy reasoned that Riverside Bayview and
SWANCC ``establish the framework for'' determining whether an
assertion of regulatory jurisdiction constitutes a reasonable
interpretation of ``navigable waters''--``the connection between a
non-navigable water or wetland and a navigable water may be so
close, or potentially so close, that the Corps may deem the water or
wetland a `navigable water' under the Act;'' and ``[a]bsent a
significant nexus, jurisdiction under the Act is lacking.'' 547 U.S.
at 767. ``The required nexus must be assessed in terms of the
statute's goals and purposes. Congress enacted the law to `restore
and maintain the chemical, physical, and biological integrity of the
Nation's waters,' 33 U.S.C. 1251(a), and it pursued that objective
by restricting dumping and filling in `navigable waters,' sections
1311(a), 1362(12).'' Id. at 779. ``Justice Kennedy concluded that
the term ``waters of the United States'' encompasses wetlands and
other waters that ``possess a `significant nexus' to waters that are
or were navigable in fact or that could reasonably be so made.'' Id.
at 759. He further concluded that wetlands possess the requisite
significant nexus: ``if the wetlands, either alone or in combination
with similarly situated [wetlands] in the region, significantly
affect the chemical, physical, and biological integrity of other
covered waters more readily understood as `navigable.' '' Id. at
780.
    While Justice Kennedy's opinion focused on adjacent wetlands in
light of the facts of the cases before him, the agencies determined
it was reasonable and appropriate to undertake a detailed
examination of the scientific literature to determine whether
tributaries, as a category and as the agencies propose to define
them, significantly affect the chemical, physical, or biological
integrity of downstream navigable waters, interstate waters, or
territorial seas into which they flow. Based on this extensive
analysis, the agencies concluded that tributaries with bed and
banks, and ordinary high water marks, alone or in combination with
other tributaries, as defined by the proposed regulation, in the
watershed perform these functions and should be considered, as a
category, to be ``waters of the United States.''
    The assertion of jurisdiction over this category of waters is
fully consistent with Justice Kennedy's opinion in Rapanos.
``Justice Kennedy concluded that the term ``waters of the United
States'' encompasses wetlands and other waters that ``possess a
`significant nexus' to waters that are or were navigable in fact or
that could reasonably be so made.'' Id. at 759. With respect to
tributaries, Justice Kennedy rejected the plurality's approach that
only ``relatively permanent'' tributaries are within the scope of
CWA jurisdiction. He stated that the plurality's requirement of
``permanent standing water or continuous flow, at least for a period
of `some months' . . . makes little practical sense in a statute
concerned with downstream water quality.'' Id. at 769. Instead,
Justice Kennedy concluded that ``Congress could draw a line to
exclude irregular waterways, but nothing in the statute suggests it
has done so;'' in fact, he stated that Congress has done ``[q]uite
the opposite . . ..'' Id. at 769. Further, Justice Kennedy
concluded, based on ``a full reading of the dictionary definition''
of ``waters,'' that ``the Corps can reasonably interpret the Act to
cover the paths of such impermanent streams.'' Id. at 770 (emphasis
added).
    Moreover, Justice Kennedy's opinion did not reject the agencies'
existing regulations governing tributaries. The consolidated cases
in Rapanos involved discharges into wetlands adjacent to
nonnavigable tributaries and, therefore, Justice Kennedy's analysis
focused on the requisite showing for wetlands. Justice Kennedy
described the Corps' standard for asserting jurisdiction over
tributaries: ``the Corps deems a water a tributary if it feeds into
a traditional navigable water (or a tributary thereof) and possesses
an ordinary high water mark . . ..'' Id. at 781, see also id at 761.
He acknowledged that this requirement of a perceptible ordinary high
water mark for ephemeral streams, 65 FR 12828, March 9, 2000,
``[a]ssuming it is subject to reasonably consistent application, . .
. may well provide a reasonable measure of whether specific minor
tributaries bear a sufficient nexus with other regulated waters to
constitute navigable waters under the Act.'' 547 U.S. at 781, see
also id. at 761. With respect to wetlands, Justice Kennedy concluded
that the breadth of this standard for tributaries precluded use of
adjacency to such tributaries as the determinative measure of
whether wetlands adjacent to such tributaries ``are likely to play
an important role in the integrity of an aquatic system comprising
navigable waters as traditionally understood.'' Id. at 781. He did
not, however, reject the Corps' use of ``ordinary high water mark''
to assert regulatory jurisdiction over tributaries themselves. Id.
    In the foregoing passage regarding the existing regulatory
standard for ephemeral streams, Justice Kennedy also provided a
``but see'' citation to a 2004 U.S. General Accounting Office (now
the U.S. Government Accountability Office) (GAO) report ``noting
variation in results among Corps district offices.'' Id. In 2005,
the Corps issued a regulatory guidance letter (RGL 05-05) to Corps
districts on OHWM identification that was designed to ensure more
consistent practice. The Corps has also issued documents to provide
additional technical assistance for problematic OHWM delineations.
See, e.g., R.W. Lichvar and S.M.

McColley, U.S. Army Corps of Engineers, A Field Guide to the
Identification of the Ordinary High Water Mark (OHWM) in the Arid
West Region of the Western United States: A Delineation Manual,
ERDC/CRREL TR-08-12 (2008). Moreover, the agencies propose today for
the first time a regulatory definition of ``tributary.'' The
definition expressly addresses some of the issues with respect to
identification of an OHWM that caused many of the inconsistencies
reported by the GAO. For example, this proposed regulation clearly
provides that a water that otherwise meets the proposed definition
of tributary remains a jurisdictional tributary even if there are
natural or man-made breaks in the OHWM. The proposed definition also
provides a non-exclusive list of examples of breaks in the OHWM to
assist in clearly and consistently determining what meets the
definition of tributary.
    Most fundamentally, the agencies believe that the scientific
literature demonstrates that tributaries, as a category and as the
agencies propose to define them, play a critical role in the
integrity of aquatic systems comprising traditional navigable waters
and interstate waters, and therefore are ``waters of the United
States'' within the meaning of the Clean Water Act.

Adjacent Waters

    The CWA explicitly establishes authority over adjacent wetlands.
Under section 404(g), states are authorized to assume responsibility
for administration of the section 404 permitting program with
respect to ``navigable waters (other than those waters which are
presently used, or are susceptible to use in their natural condition
or by reasonable improvement as a means to transport interstate or
foreign commerce shoreward to their ordinary high water mark,
including all waters which are subject to the ebb and flow of the
tide shoreward to their mean high water mark, or mean higher high
water mark on the west coast, including wetlands adjacent
thereto).'' 33 U.S.C. 1344(g)(1) (emphasis added). While this
provision mainly serves as a limitation on the scope of waters for
which states may be authorized to issue permits, it also shows that
Congress was concerned with the protection of adjacent wetlands and
recognized their important role in protecting downstream traditional
navigable waters. Indeed, the existing definition of adjacency was
developed in recognition of the integral role wetlands play in
broader aquatic ecosystems:

The regulation of activities that cause water pollution cannot rely
on . . . artificial lines . . . but must focus on all waters that
together form the entire aquatic system. Water moves in hydrologic
cycles, and the pollution of this part of the aquatic system,
regardless of whether it is above or below an ordinary high water
mark, or mean high tide line, will affect the water quality of the
other waters within that aquatic system. For this reason, the
landward limit of Federal jurisdiction under Section 404 must
include any adjacent wetlands that form the border of or are in
reasonable proximity to other waters of the United States, as these
wetlands are part of this aquatic system.

42 FR 37128, July 19, 1977.
    As the Supreme Court found in United States v. Riverside Bayview
Homes, Inc., ``the evident breadth of congressional concern for
protection of water quality and aquatic ecosystems suggests that it
is reasonable for the Corps to interpret the term `waters' to
encompass wetlands adjacent to waters as more conventionally
defined.'' 474 U.S. at 133.
    In upholding the Corps' judgment about the relationship between
waters and their adjacent wetlands, the Supreme Court in Riverside
Bayview acknowledged that the agencies' regulations take into
account functions provided by wetlands in support of this
relationship. ``[A]djacent wetlands may `serve significant natural
biological functions, including food chain production, general
habitat, and nesting, spawning, rearing and resting sites for
aquatic . . . species.' '' Id. at 133 (citing Sec.  320.4(b)(2)(i)).
The Court further stated that the Corps had reasonably concluded
that ``wetlands adjacent to lakes, rivers, streams, and other bodies
of water may function as integral parts of the aquatic environment
even when the moisture creating the wetlands does not find its
source in the adjacent bodies of water.'' 474 U.S. at 135.
    Two decades later, a majority of justices in Rapanos concluded
that the agencies' regulatory definition of adjacent wetlands
reasonable. Justice Kennedy stated:

As the Court noted in Riverside Bayview, `the Corps has concluded
that wetlands may serve to filter and purify water draining into
adjacent bodies of water, 33 CFR 320.4(b)(2)(vii)(1985), and to slow
the flow of surface runoff into lakes, rivers, and streams and thus
prevent flooding and erosion, see Sec.  320.4(b)(2)(iv) and (v).'
Where wetlands perform these filtering and runoff-control functions,
filling them may increase downstream pollution, much as a discharge
of toxic pollutants would.. . . In many cases, moreover, filling in
wetlands separated from another water by a berm can mean that flood
water, impurities, or runoff that would have been stored or
contained in the wetlands will instead flow out to major waterways.
With these concerns in mind, the Corps' definition of adjacency is a
reasonable one, for it may be the absence of an interchange of
waters prior to the dredge and fill activity that makes protection
of the wetlands critical to the statutory scheme.

547 U.S. at 775 (citations omitted).
The four dissenting justices similarly concluded:

The Army Corps has determined that wetlands adjacent to tributaries
of traditionally navigable waters preserve the quality of our
Nation's waters by, among other things, providing habitat for
aquatic animals, keeping excessive sediment and toxic pollutants out
of adjacent waters, and reducing downstream flooding by absorbing
water at times of high flow. The Corps' resulting decision to treat
these wetlands as encompassed within the term `waters of the United
States' is a quintessential example of the Executive's reasonable
interpretation of a statutory provision.

Id. at 778 (citing Chevron U.S.A. Inc. v. Natural Resources Defense
Council, Inc., 467 U.S. 837, 842-845 (1984)).
    For those wetlands adjacent to traditional navigable waters,
Justice Kennedy concluded in Rapanos that the agencies' existing
regulation ``rests upon a reasonable inference of ecologic
interconnection, and the assertion of jurisdiction for those
wetlands is sustainable under the Act by showing adjacency alone.''
547 U.S. at 780. For other adjacent waters, including adjacent
wetlands, Justice Kennedy's significant nexus standard provides a
framework for establishing categories of waters which are per se
``waters of the United States.'' First, he provided that wetlands
are jurisdictional if they ``either alone or in combination with
similarly situated lands in the region, significantly affect the
chemical, physical, and biological integrity of other covered waters
more readily understood as `navigable.' '' Id. at 780. Next, Justice
Kennedy stated that ``[t]hrough regulation or adjudication, the
Corps may choose to identify categories of tributaries that, due to
their volume of flow (either annually or on average), their
proximity to navigable waters, or other relevant considerations, are
significant enough that wetlands adjacent to them are likely, in the
majority of cases, to perform important functions for an aquatic
system incorporating navigable waters.'' Id. at 780-81.
    While the issue was not before the Supreme Court, it is
reasonable to also assess whether non-wetland waters have a
significant nexus, as Justice Kennedy's opinion makes clear that a
significant nexus is a touchstone for CWA jurisdiction. The agencies
have determined that adjacent waters as defined in today's proposed
rule, alone or in combination with other adjacent waters in the
region that drains to a traditional navigable water, interstate
water or the territorial seas, significantly affect the chemical,
physical, and biological integrity of those waters. As explained in
more detail in Section H, below, the proposed rule interprets the
phrase ``in the region'' to mean the watershed that drains to the
nearest traditional navigable water or interstate water through a
single point of entry. The agencies have determined that because the
movement of water from watershed drainage basins to river networks
and lakes shapes the development and function of these systems in a
way that is critical to their long term health, the watershed is a
reasonable and technically appropriate reflection of Congressional
intent.
    The agencies have concluded that all waters that meet the
proposed definition of ``adjacent'' are similarly situated for
purposes of analyzing whether they, in the majority of cases, have a
significant nexus to an (a)(1) through (a)(3) water. Based on the
agencies' review of the scientific literature, we have concluded
that these waters, when bordering, contiguous or located in the
floodplain or riparian area, or when otherwise meeting the
definition of ``adjacent,'' provide many similar functions that
significantly affect the chemical, physical, or biological integrity
of traditional navigable waters, interstate waters, or the
territorial seas. Further, because the proposed definition generally

focuses on the location of the waters (i.e., those that are located
near (a)(1) through (a)(5) waters), interpreting the term
``similarly situated'' to include all adjacent waters, as defined in
the proposed rule, is reasonable and consistent with the science.
The geographic position of an ``adjacent'' water relative to the
tributary is indicative of the relationship to it, with many of its
defining characteristics resulting from the movement of materials
and energy between the categories of waters. The scientific
literature documents that waters that are adjacent to (a)(1) through
(a)(5) waters, including wetlands, oxbow lakes and adjacent ponds,
are integral parts of stream networks because of their ecological
functions and how they interact with each other, and with downstream
traditional navigable waters, interstate waters, or the territorial
seas. In other words, tributaries and their adjacent waters, and the
downstream traditional navigable waters, interstate waters, and
territorial seas into which those waters flow, are an integrated
ecological system, and discharges of pollutants, including
discharges of dredged or fill material, into any component of that
ecological system, must be regulated under the CWA to restore and
maintain the chemical, physical, or biological integrity of these
waters.
    Based on the science, as summarized below, the agencies have
concluded that wetlands and waters adjacent to all tributaries that
meet the proposed definition of ``tributary'' provide vital
functions for downstream traditional navigable waters, interstate
waters, or the territorial seas. In particular, the scientific
literature supports the conclusion that waters adjacent to all