What is a slurry seal?

A slurry seal is a mixture of fine aggregate, liquid asphalt and water that is spread over the pavement by a County hired contractor. Slurry seals are used on arterial, collector and residential roads that are in good condition. Schedule information regarding the contracted slurry seal application can be obtained by calling the Public Works Department’s Construction Division at (925) 313-2320.

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1. What are Area of Benefit (AOB) funds used for?
2. What are Best Management Practices (BMPs)?
3. What are Pollutants of Concern (POCs)?
4. What are the Public Works Counter hours of service, phone numbers, and location?
5. What can property owners do to help the County's maintenance efforts of private trees and other vegetation?
6. What can property owners do to prevent fallen leaves from creating blockages in the drainage system?
7. What do I do if my neighbor informed me that I am encroaching on his property?
8. What information should I provide when reporting a streetlight outage?
9. What is a cape seal?
10. What is a chip seal?

The County Public Works Department Maintenance crews perform two types of chip seal:

•    A single chip seal involves spraying liquid asphalt on the pavement followed by the spreading of a layer of small aggregate (chips) that is embedded into the oil.

•    A double-chip seal is a single chip seal with a second application (layer) of liquid asphalt and small aggregate.  

Single and double-chip seals are typically used on arterial and collector roads that have a significant amount of wear and high traffic volume. Schedule information regarding the chip seal application can be obtained by calling the Public Works Department Maintenance Division at (925) 313-7000, or you can visit our Pavement Management Program page.

11. What is a micro-surface seal?
12. What is a slurry seal?
13. What is a traffic Area of Benefit (AOB)?
14. What is a Watershed?
15. What is an illicit discharge and who do I call to report it?
16. What is an NOI and what permits does it cover?
17. What is C.3?
18. What is IPM and what are some ways I can try it?
19. What is NPDES and who oversees it?
20. What is the Adopt-A-Road Program?
21. What is the basis of the Area of Benefit (AOB) Program?

The Area of Benefit (AOB) Program is based on the following government codes:

  1. California Government Code Section 66000-66025 (Mitigation Fee Act)
  2. California Government Code Section 66484 (Subdivision Map Act)
  3. Title 9 Division 913 of the Contra Costa County Ordinance Code
22. What is the construction work occurring on a County Road or Flood Control Facility?
23. What is the CRIPP?
24. What is the County's responsibility in maintaining private drainage systems?

Contra Costa County has 31 major watersheds and sub-watersheds containing more than 1,300 miles of creeks and drainages. Of that total, the County maintains approximately 75 miles of improved creeks and drainages. The rest is the responsibility of private property owners.

The County maintains only those drainage facilities required as a condition of development constructed to standards applicable at the time of construction and located in an easement or other land right accepted by the County. Creek maintenance is the responsibility of the owner whose property abuts a creek.

When the creek area is not properly maintained, the resulting obstructions can lead to increased flooding, changes in the course of the creek, and increased erosion on the obstructed property and/or downstream properties. See Division 1010 of the Title 10 County Ordinance Code for more information on. The Public Works Department recommends the following guidelines on private creek maintenance (PDF).

25. What is the design storm for my project?
26. What is the difference between a Stormwater Pollution Prevention Plan (SWPPP) and a Stormwater Control Plan (SWCP)?
27. What is the difference between point source and non-point source?
28. What is the difference between the County Watershed Program and the Contra Costa Clean Water Program?
29. What is the difference between the storm drain system and the sanitary sewer?
30. What is the drainage easement across my property? Can I build on it? What can I do on it?
  1. Easements provide the Public Works Department and Flood Control District with land rights for construction, reconstruction, maintaining and accessing its drainage facilities and for other related purposes. Some access easements are not used regularly but must be kept clear for potential future use. An easement allows the property owner use of the property as long as it does not interfere with easement rights.
  2. No permanent structures or encroachments will be permitted or constructed within or over any drainage easement. This includes, but is not limited to:
  • fill slopes
  • retaining walls
  • fencing
  • sheds
  • landscaping
           Any such obstructions will be removed as necessary for maintenance and access purposes and will not be repaired or replaced (Title 0; 914-14.010).

31. What is the Public Works Budget?
32. What projects are upcoming or currently advertised?
33. What should I do if I see someone dumping garbage on private or public property?