Table 5.2. BOD Transfer to River, by Industry Groups for Three Levels of River Flow, 

 Optimal Net Benefit Resource Allocation, Current River Quality (BCC), 

 Ashuelot River Basin 



' Reduction in BOD from median flow is due in part to reduced output. 

 Maximum net benefits = REVOWAT 



differ with different flow conditions. Much in terms of savings in expenditures 

 and opportunity for growth can be achieved in coordinated effort for meeting 

 common goals. 



5.4 Influence of River-Flow Level on Benefits and Costs 



River-flow level is directly related to assimilative capacity of the receiving 

 water body. 



The influence of flow level on the river basin can be aggregated in terms of 

 net benefits (REVOWAT) and public and private costs of providing water used 

 and waste-water treatment (SOCCOST). The influence of river flow on the 

 former is shown in Table 5.3 and the latter in Table 5.4. 



Moving from a higli-flow level to a median-flow level has a relatively small 

 effect on net benefits or minimum costs.' In a marginal sense, and moving 

 from median flow to low flow, net benefits dechne by a substantial amount. At 

 the low-flow levels, incremental costs rise rapidly as river flow decreases; at the 

 median-flow levels, cost and net benefits change less as flow level increases. The 

 most useful results would appear to be found at the median- and low-flow levels. 

 It is over this range that net benefits and cost change at the most rapid rate. 



5.5 Value of Low-Flow Augmentation 



Low-flow augmentation is a means of increasing assimilative capacity. The 

 value of this activity must be weighed against alternatives in achieving specified 

 goals. A crude approximation was developed from the change in net benefits 

 associated with change in river flow and presented in Table 5.5. The estimate 

 is based on variable cost and implies that on the average and for low-flow months, 

 flow augmentation has a value of about five cents per 1 ,000 gallons. If fixed costs 



'The optimal solutions at high- and median-flow levels included more waste-water 

 treatment facihties than are now found in the basin. 



38 



