III. Considerations for Protection of Instream Flow
As outlined in the nomination, the Department assisted the IRPP in an assessment of registered water withdrawals (>20,000 gpd) in relation to the proposed draft instream flow rules dated June 1, 2001 ("proposed rules"). The assessment identified two active registered water users within the Isinglass watershed, namely the Cities of Rochester and Dover. Both communities utilize surface waters within the watershed as municipal water supplies.
Monthly reporting records were compared to estimated stream flows within the framework of the General Standard outlined in the proposed rules. The assessment yielded important information relative to the two registered users. With respect to the City of Rochester, water is diverted from the Berry's River, a tributary to the Isinglass, to its reservoir and is subsequently reported as lump sum of treated water being drawn from the reservoir. Thus, without a quarterly reporting record from the Berry's River proper, it is not possible to determine the amount of water withdrawan on an instantaneous basis from the Berry's River. It is clear from field inspection and hydrologic estimates, that the amount of water diverted from the Berry's River to the reservoir would exceed the General Standard. However, the extent and duration of this exceedance cannot be determined at this time.
In contrast, the City of Dover's water monthly average withdrawal records from 1994-98 were compared to estimated stream flows. Under the General Standard, 5 months (April, May, July, October, and November) were identified in which water use exceeded exceeded the General Standard.
Although the apparent exceedances of the General Standard understandably raises concerns in the respective communities, there are three important points that must be noted. First, the water use records utilized for this analysis represent an average of four years of data, rather than a given month within a single year. Second, stream flows from the Isinglass are estimates since no current or historical gage data exist from this river. Third, and most importantly, under the proposed rules the General Standard would be utilized as a framework for prioritizing watersheds through which designated rivers flow that are in need of additional study for establishing watershed-specific instream flow standards and development of a water use management plan. The General Standard should not be viewed as an ultimate quantitative water use threshold. Rather, based on the analysis completed for the nomination, it is apparent that the Isinglass would be one of many watersheds through which designated rivers flow that do not meet the General Standard under the proposed rules. Thus, any changes in water usage by the Cities of Rochester or Dover would not occur immediately upon designation. Under the "proposed rules" the Department would create a priority list for those designated rivers or sections of designated rivers that require additional water use planning. In turn, any further action on the priority list would be subject to legislative oversight, funding appropriation, an intensive river-specific study to determine the flows that are protective of the all the river's uses, including public water supply, and a negotiated water management plan that outlines each users allocation of available water.