canning dam canning dam reservoir provide major fresh water resource city perth western australia dam situated noted innovative structural hydraulic design considered forefront concrete gravity dam design time construction canning dam perth primary water supply 1960s sources fresh water tapped currently dam supplies approximately percent perth fresh water estimated storage capacity completion canning dam contributed wide range environmental ecological problems surrounding regions problems include common habitat loss despite issues adjacent parks forests provide variety recreational activities public historic walks picnic facilities history development canning river source water perth proposed report perth investigation site began engineer surveyed proposed dam current location possible site despite recommendations inquiries extreme shortage water years government funds allocated construction dam great depression 1930s small dam built kilometres downstream present canning dam intended quick fix water supply problem soon apparent major reservoir needed years work current canning dam begin new dam completed cost million designed dam directed construction improvement concrete lined channel constructed divert stream flow nearby canning dam reservoir perth primary source water boom growth city 1960s completion dam reservoir connected perth prior opening water flowed canning dam reservoir supplies approximately percent perth drinking water requirements plays important role context development perth canning reservoir store water newly completed treated water pumped plant reservoir new canning dam lies forms composed largely granite invaded linear belts volcanic rocks dam wall situated narrow gorge running east west rock sides sloping upward river bed dam wall south branch joins main stream water forming lake stretches major arms east south east south area square kilometres reservoir metres highest point metres area receives millimetres rainfall falling september widespread rainfall millimetres long term average dam wall decreased percent approximately percent average annual reduced construction construction canning dam ended long period perth water supply generally unsatisfactory quality pollution quantity project biggest public works program decade stimulated significant growth local economy provided desperately needed work men innovative design concepts construction methods new australia introduced project nearby improved canning dam site canning dam dams care taken prevent water foundation rock structure dam canning addition cutting foundation solid rock cut trench sited near upstream face dam stream rock filled drain containing open pipes provided intercept rock face concrete dam inclusion internal drainage system considered innovative period near vertical tubular cut drains provided foot intervals dam relieve internal concrete state art materials handling methods instances labour saving machinery worked operations intended labour content workers employed chiefly site preparation road construction foundation excavation clearing timber reservoir basin operations skilled workers required dam fixing concrete poured workers probably employed normal day labour rates main employment method project bulk handling cement time australia saw significant saving opposed cement standard practice day generally construction work proceeded smoothly engineering point view setbacks occur early stages construction march violent storm bringing rain days result river rose rapidly flooded dam foundation workings pumps installed work resumed days later dam completed september built longest concrete gravity dam australia second highest new_south_wales large concrete masonry gravity dams australia canning dam fifth highest sixth longest largest concrete dam western_australia terms length crest volume concrete final cost dam significantly originally work completed schedule date calculated seven years previously works recently canning dam subjected considerable cracking upper parts dam upper gallery investigations shown cracking strong aggregate concrete results swelling concrete cause secondary stresses map cracks ultimately structural cracks addition concrete strength significantly decreases old concrete dams known suffer including tennessee dam italy extensive works undertaken strengthen dam wall work involved removing existing dam wall drilling blasting dam wall plus bedrock section wall rebuilt reinforced concrete finally permanent ground anchors installed formed holes crest stressed foundation rock time completion largest capacity longest permanent ground anchors installed world innovative drilling blasting technique called works process chosen conventional drilling blasting techniques reduced risk damage existing structure vibration lower dust levels environmental issues construction drinking water supply dams water flow reduced number freshwater fish species endemic south west western_australia found system studies fish fish habitats area shown fish numbers low loss habitat loss breeding areas low flows preventing fish migrating upstream reaching important breeding nursery grounds water caused lack water flow provided suitable habitat successful breeding introduced pest canning caused dramatic flow reductions significantly altered downstream aquatic communities lack water flow resulted poor effect dam wall excessive nutrients animal waste caused river pools important summer refuge habitat aquatic terrestrial flora fauna lost modification flow regime caused periodic flooding dam required disperse seed stimulate ensure survive shallow tables important periods drought discourage prevent growth times low rainfall periodic flooding reduced recreation number recreation activities occur dam area canning dam features number picnic areas gas look outs historic walks disabled access occurs particularly track passes upstream canning dam mountain bike trails run adjacent areas tributaries illegally especially summer boating fishing swimming prohibited reservoir health reasons camping including overnight stays outside designated areas trail establishment occur frequently canning gallery
Canning Dam