228.22 Municipal uses – Examined costs in 2 major urban areas: Southern California (Los Angeles...
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Transcript of 228.22 Municipal uses – Examined costs in 2 major urban areas: Southern California (Los Angeles...
Municipal uses – Examined costs in 2 major urban areas: Southern California (Los Angeles south to San Diego) & Central Arizona (Phoenix)
Recreation – $0.03 – 0.13 billionLimited data availabilitySome uses are not valuable, but rafting and kayaking are valuableFor Green River and Colorado River above Lake Mead, value of
lost water for boating estimated at $0.5 – 2.3 million per year
Underestimates total value because only considers part of system
Flood control – $2.9 billionTamarisk stand trap sediments, which leads to a narrowing river
channel, and narrowing of the flood plainNarrower channels means channel can hold less water, which
means floods at lower volumes of waterPlus the dense vegetation backs-up the water , spreading it out
over a larger areaThus get more frequent and large floodsUsed Army Corps of Engineer’s conservative estimates of extra
flood damage due to Tamarisk of $52 million per year times 55 years
1953
1998
CHANGES IN RIPARIAN VEGETATION IN THE SOUTHWESTERN UNITED STATES: Floods and Riparian Vegetation on the San Juan River, Southeastern Utah-- USGS
Sedimentation – Benefits of $0.07 billionTamarisk traps sediments, and hence increases lifetime of
reservoirs
Dove hunting – Benefits of $0.02 billionDoves like Tamarisk thicketsIncreases value for hunting
Add up the total losses & benefits• Municipal uses $1.4 – 3.7 billion• Agricultural uses $2.1 – 6.7 billion• Hydroelectric power $0.8 – 2.4 billion• Recreation $0.03 – 0.13 billion• Flood control $2.9 billion• Wildlife $0.09 – 0.37 billion• Sedimentation - $0.07 billion• Dove hunting - $0.02 billion
________________TOTAL $7.3 – 16.1 billion loss
Case study: Klamath weed (Hypericum perforatum)• Broad-leaved, perennial herb• Introduced from Europe in 1793; reached California
late 1800’s• Extremely invasive; toxic• By early 1940’s: 5 million acres of infested rangeland• Biological control in California
1945/1946: 2 leaf feeders introduced1950: root feeder introducedTotal Cost: $750,000
• By early 1960’s in California, insects had reduced Klamath weed acreage to <1% of peak acreage
• Annual benefits estimated @ $3,500,000 per year in CaliforniaTotal Benefits (1965 – 2005): $140 millionBenefit : Cost ratio = 187 : 1 (not adjusted for
inflation)
Case study: Eurasian watermilfoil (Myriophyllum spicatum)From Eiswerth et al. (2000) Weed Technology 14:511-518• Aquatic weed that forms dense, floating mats• Introduced to Chesapeake Bay in 1880’s; now widespread throughout US• Spreads primarily by plant fragments• Population reported at Lake Tahoe since 1960’s• Economic impacts include
↓ recreational activities (fishing, boating, swimming, etc.)Clog irrigation canals, gates, etc.↓hydroelectric generation by clogging intake pipesNon-use value: degradation of Lake Tahoe
Study only focused on recreational uses• Low & high economic values for 4 sites in
Lake Tahoe – Truckee – Pyramid watershedIf 100% infestation, lose $30-45 million per yearIf 5% infestation, lose >$1 million per year
South African fynbosEucalypts, pines, Acacias, and other species have invaded the
fynbos of South Africa’s Cape Province