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Show PART VI FRAMEWORK PLAN AND ALTERNATIVES Watershed management and flood control Watershed jManagement Average annual upstream watershed damage is presently $8.71 million. This will increase to $25.6 million by the year 2020 if no additional pro- tection programs are initiated after 1965 due to population, growth, and economic activity. The program of upstream watershed management prac- tices, including land treatment and water control structures, is listed in Table 8. Man-created erosion and sediment production and associated damage will be decreased kO to 60 percent. Upstream flood and sediment damage will be reduced about 30 to 50 percent. In addition, applied man- agement practices can improve water yield in terms of quantity, quality, and timing. Flood Control Average annual flood damage in the region would increase to an esti- mated value of $10,551,000 by year 2020 with no additional flood control measures after 1965. The flood control plan consisting of flood control storage in reservoirs, levees, and channels; improved flood forecasting; land treatment; and other nonstructural measures would reduce the esti- mated average annual flood damage in 2020 by $6,7^,000 or about 65 per- cent of the amount that would occur without the program. The structural components of the plan are shown in the table below. Nonstructural mea- sures, such as zoning, flood proofing, use of building codes, subdivision regulations, and other similar techniques to limit flood damage at the principal urban areas of the region, are also included in the plan. Flood control programs Framework plan Upper Colorado Region Multiple- Single-purpose programs Sub region Time frame purpose reservoir capacity (1,000 acre-feet) Land treatment!/ (1,000 acres) Reservoir capacity (1,000 acre- Levees feet) (miles) Channels (miles) Green River 1980 2000 2020 1+66 123 75 97h 1,302 527 21 1+6 28 0 0 0 3.6 0 Upper Main Stem 1980 2000 2020 1,172 293 0 61+1 873 308 7 20 6 0 2.0 0 3.0 0 0 San Juan-Colorado 1980 2000 2020 1 0 20 797 921+ 766 2 11+ 6 0 0 2.0 0 1+.0 0 Region 1980 2000 2020 1,639 1+16 95 2,1+16 3,099 1,601 30 80 1+0 0 l.h 2.0 3.0 7.6 0 Region total 2,150 7,112 150 9-h 10.6 1/Included in watershed management program 66 |
