This area, at the extreme head of Cohocton River, is naturally tributary to Chemung and Susquehanna Rivers.
An excellent site for a diversion dam and reservoir exists on this area at a suitable elevation to permit water to be diverted to be conveyed into Springwater Creek drainage basin by gravity.
A covered concrete conduit would lead from the reservoir, following approximately between 1300 and 1400 foot contours, into the head of Springwater Creek north of Wayland. This would provide an area of 11.16 square miles in area "A", and an additional area, "B", of 1.15 square miles, from which water could be diverted into the same conduit (Fig. 2). The drainage basin is clean rural area, containing only one small hamlet.
This project would, however, involve diversion from the drainage basin of an interstate stream.
It may be noted that there is already a similar diversion of most of the water from an area of 45 square miles from Mud Creek, naturally tributary to Cohocton River near Bath. This diversion, by the Lamoka Power Corporation, into Keuka Lake, began about 1929. The natural low water flow is, I understand, released to the stream.
In this connection a precedent is established for diversion by the decision of the U. S. Supreme Court in the so-called Delaware River case (Master's Report and decision of the U. S. Supreme Court, State of N. J. vs State and City of N. Y., case of original jurisdiction No. 17, U. S. Supreme Court.) In this case the writer represented the State of New Jersey as Chief Engineer.
In this case New York City proposed to divert 600 mgd from Delaware River in New York State, and action for injunction was brought by the State of New Jersey but permanent injunction was denied, although the permissible diversion was reduced to 440 mgd.
In the present instance argument might be made that this diversion of the Cohocton area is unnecessary, as Rochester already has another approved source of supply on Honeoye Creek. A similar situation existed in the Delaware River Case, New York City having previously reported favorably on a supply of equal volume from sources east of Hudson River and lying wholly within New York State, but afterwards, by official action, the City adopted the Delaware River source. The Special Master held that the question of necessity could not be entered into as the City had the right to determine the most advantageous and desirable source of its water supply.
While, of course, the Cohocton diversion would represent a technical invasion of property rights, the court held in the New Jersey case that before an injunction could be granted, something more than trivial damage must be shown. Also it was held by the Supreme Court in that case that the question of use of an interstate stream rested primarily on a reasonable and equitable diversion and use of the stream rather than on the ordinary principles of common law.
There are important waterpower developments on lower Susquehanna River. However, the area to be diverted, namely, 12.3 square miles, is so small compared with the total area of over 25,000 square miles at the location of the principal power developments that this question, if it arises, should be capable of ready adjustment.
The principal developments are: Head, Drainage area, feet square miles Conowingo ........................ 89 ............... 27,000 Safe Harbor ...................... 53 ............... 26,000 Holtwood ......................... 53 ............... 25,000
If the entire flow was diverted and if it could all be used for power, the loss of power would be roundly 200 hp.
The Cohocton diversion would turn water into Springwater Creek. There would be some increase in flood discharge of that stream but never in excess of the capacity of the diversion conduit. Some flood channel improvement on Springwater Creek should be made.
Pending completion of surveys, determination of the available sizes of intake reservoirs and the economic sizes of diversion conduits cannot be made.
The suggestion naturally occurs that since at least 10 mgd additional supply can be obtained from Calabogue and Cohocton drainage basins, outside the Hemlock Lake Basin, why not bring these sources in at once, making this the first step in the program? The answer is, of course, that storage for regulation of this added inflow is not at present available and the first step therefore be to provide additional storage space.
Upon completion of the project, with the bringing in of the Cohocton area, the drainage area tributary t o the Hemlock system will be roundly 100 square miles and the net dependable supply at least 50 mgd, after allowing a reserve storage in Hemlock Reservoir of 10% for Emergency use.