-Some parts of a watershed may require such costly treatments for stabilization 

 that their application for sediment reduction is not feasible; it would be far less 

 expensive to dredge out an equivalent amount of deposit. Other parts of a watershed 

 may feasibly be trenched, furrowed, ripped, or harrowed at reasonable cost. The costs 

 and benefits of various treatment schedules must be evaluated in order to rank treatable 

 areas by priority for treatment. 



VsTien grazing opportunities are included in the evaluation, priorities might change. 

 With good cost-treatment response data coupled with information on consequences of 

 grazing intensity, a Linear Program solution to optimize some objective function, 

 subject to budget and land use constraints, would indicate different priorities depend- 

 ing on the levels of use and money specified as available. The data for North Dragon 

 indicated that using a given budget, sediment reduction could be increased 15 acre-inches 

 per year (from 117 to 132) by dropping grazing from 500 to 100 AUM's. The areas desig- 

 nated for treatment (priorities for treatment) also changed. This simply means that 

 the kind and level of any land use affect not only the final results of treatment, but 

 also influence the preferred ranking of treatments and selection of areas to treat in 

 order to meet objectives and stay within the bounds of the constraints. These influ- 

 ences must be taken into account early in the planning of watershed projects. 



Budget Levels 



Establishing a budget level for a particular watershed project is a most difficult 

 task; many factors must be considered and good cost-response data are mandatory. Also, 

 some definite goals or objectives must be set--how much erosion is to be stopped or 

 sediment delivery reduction to be achieved. The "Let's git 'eri" approach to stabiliza- 

 tion and rehabilitation implies at least two things, both of which are untrue. First, 

 it implies that given enough money, all erosion on the watershed could be stopped. 

 Second, it implies that stopping as much erosion as is physically possible is worth 

 whatever it will cost. 



It is unreal to assume that all erosion and sedimentation can be stopped. On 

 North Dragon, only about 10 acre-feet of sediment can be kept out of the reservoir 

 annually by the best and most appropriate treatment of areas where treatment is feas- 

 ible; geologic erosion cannot be stopped. 



It is equally unreal to assume that whatever it would cost to achieve the minimum 

 erosion and sediment delivery would be worth it. For .North Dragon, the marginal cost 

 of reducing sediment skyrockets after the use of treatments costing up to about $50 

 per acre-inch reduction (for hydrologic type IP) as the data for furrowing illustrate 

 (table 1). (The same is also true for trenching on North Dragon.) By treating hydrol- 

 ogic types 9C through IP, costs of $30,840 result in a total sediment reduction of 

 1,743 acre-inches (145 acre-feet) over an 80-year period. Treating the remaining 

 hydrologic areas resulted in a total furrowing cost of $37,980 and a total sediment 

 reduction of 1,819 acre-inches (151 acre-feet). That means that the last 76 acre-inches 

 (6 acre-feet) cost $7,140, or about $94 per acre-inch (or an average of $1,128 per acre- 

 foot). The sediment reduction on hydrologic type 4C costs $133 per acre-inch ($1,596 

 per acre-foot) by furrowing, and on hydrologic t\'pe 5E a treatment cost of $225 resulted 

 in no additional sediment reduction. (It might well be cheaper to haul out the last 

 6 acre-feet of sediment after it is deposited.) 



As in all spending situations, beyond some point the marginal cost of additional 

 benefits becomes excessive. That is, an infinite amount of money will buy virtually 

 no additional benefits. In this case it appears that no more than $32,000 could be 

 justified on furrowing (fig. 1). 



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