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Under Attack
New York's Kensico and West Branch Reservoirs Confront Intensified Development

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The West Branch Reservoir is located in Putnam County, in the towns of Carmel and Kent, approximately 35 miles north of New York City. It consists of two basins, separated by NY State Route 301. Although this reservoir receives water from its own small watershed and the Boyd Corners Reservoir to its northwest, most of the water in the West Branch now arrives from the West-of-Hudson Delaware system reservoirs via the Delaware Aqueduct. (See Map 1.) The West Branch Reservoir, which holds 10 billion gallons at full capacity, has a 19.9 square mile watershed that has, in recent years, become a location for intensifying development and a source of increasing pollution threats.

Like the Kensico Reservoir, the West Branch serves a crucial function in providing water to nearly half of the state's population. Although it is geographically located in the Croton watershed, its primary role is to serve as a settling basin for water heading from four Delaware system reservoirs to New York City. Water withdrawn from the West Branch usually is sent to the Kensico Reservoir before entering the city's water supply distribution system. The West Branch serves as a crucial back-up to Kensico and as the city's "insurance policy" in the event of a problem at Kensico. When the Kensico Reservoir must be taken off-line, as has happened on several occasions in recent years, the West Branch becomes the source water reservoir for more than half a billion gallons a day of Delaware system waters, and water leaving the West Branch for the city's distribution system must then meet stringent federal standards for drinking water safety. (The West Branch also receives water from the Boyd Corners Reservoir. As such, the Boyd Corners watershed must also receive priority attention.)


The 19.9 square miles of land surrounding the West Branch Reservoir make up its relatively small watershed of under 12,000 acres. In recent years, this watershed has been the site of expanding residential development. According to one New York City DEP estimate, there are now about 1,320 residences located throughout the West Branch watershed. Information on current land use in the West Branch is sketchy. But a 1987 breakdown indicated that from 1968 to 1987, the number of acres of land developed for residential uses jumped by approximately 700 acres (to 1,768).

In the last few years, an increasing number of parcels in this crucial watershed have been converted or slated for residential development. Among the subdivisions that were recently built or are under construction, as of November 1998, were the following:

  • Cranewood Estates - the last lots of an 82 acre subdivision are now under construction;

  • Pennebrook Estates - a 21 lot subdivision is under construction on 70 acres;

  • Stony Ridge Estates - a 23 lot subdivision was recently completed on 42 acres; and

  • Laurel Farms (formerly called Meadow Crest Estates) - a 49 acre subdivision for 35 luxury homes is nearing completion on a site adjacent to New York City buffer land.

The following additional subdivision projects have been proposed by developers in the West Branch watershed:

  • McDonald and Leiner Subdivision - a ten lot residential subdivision on 36 acres;

  • Lakepointe Woods - a proposal to subdivide a 513 acre site into 102 lots with individual septic systems;

  • Michaels Glen Subdivision - a 25 lot cluster subdivision on a 29 acre site is in the review process (the project sponsors are seeking a variance to build a road within 100 feet of a watercourse);

  • Willow Pond Subdivision - a 10 lot subdivision of a 33 acre site;

  • Templand Subdivision - a 12 lot subdivision of a 14.7 acre parcel overlooking the reservoir and adjacent to New York City water supply land;

  • Horsepound Ridge - a proposal to subdivide 104 acres into 35 building lots;

  • South Sagamore Estates - a proposed subdivision of 72.44 acres into 11 lots; and

  • Land of Williams - an approved subdivision of 35 acres into 10 lots.


Many of the same problems from ill-planned development in the Kensico Reservoir basin (described above on pages 14-18) are present as well in the West Branch watershed. One difference is that the development pressures in the West Branch watershed are primarily from residential subdivision, not corporate sprawl. Yet many of the impacts of poorly planned growth are similar in both watersheds.

For example, in recent years, there have been exceedances of the coliform bacteria standard in several streams that feed into the West Branch (e.g. Horse Pound Brook and Long Pond Stream).[44] Preliminary analysis of these bacteria suggest they come from a human source of contamination such as a failing septic system.[44] DEP characterizes the water quality of these streams as only "fair" and notes that the streams may have "localized effects on reservoir water quality."[46] DEP has also reported occasional fecal coliform excursions in the reservoir itself, similar to those found in the Kensico Reservoir and possibly associated with birds roosting.[47]

The overall health of the reservoir, as measured by its trophic state index, indicates that at least parts of the West Branch have been in an unhealthy eutrophic state for much of the last decade.[48] Even more troubling, DEP data suggest that the primary reason the entire West Branch Reservoir is not exhibiting the eutrophication problems common to the city's other East-of-Hudson reservoirs is that the West Branch Reservoir's watershed flow is being diluted by water entering the reservoir from the Delaware system.[49]

To be sure, the quality of water leaving the West Branch Reservoir for Kensico and the city's distribution system remains generally high today, according to DEP. But the problems mentioned above are cautionary developments suggesting that additional protective measures are necessary to safeguard the West Branch watershed. (And since the West Branch watershed today is still less developed than the Kensico basin, it is especially well-suited for full-scale anti-sprawl and pollution prevention safeguards.) Currently, however, development in the West Branch watershed shows no signs of abating. Indeed, Putnam County is now the fastest growing county in New York State.[50] Under these circumstances, it is a mistake to believe that the current health of the West Branch Reservoir can be sustained without an intensified protection effort.


Government efforts to address the threats to the West Branch watershed have not, for the most part, moved into high gear. New York State agencies do not seem to be giving the West Branch watershed any special attention. And the New York City DEP, while recognizing the importance of this water supply, has not yet created a coordinated team to address the range of threats to West Branch. Further, neither the state nor the city has advanced a comprehensive plan to stem development and protect the crucial wetlands of the West Branch watershed.

Those actions that have been taken to safeguard the West Branch fall into three categories. First, under state Health Department rules, no new surface discharges of pollution (e.g., from sewage treatment plants) are allowed in the West Branch watershed (since waters from the West Branch reach the city's distribution system in less than 60 days). But, as DEP has warned, new subsurface discharges are not prohibited by these rules. And developers have been known to segment larger projects that would require hook-up to a surface-discharging sewage plant into several smaller developments that are allowed to advance with simple subsurface discharge systems (e.g., septic tanks). "So," DEP correctly warns, "the restriction on surface discharges may not translate into relief from development pressure, or subsequent increases in non-point source pollution."[51]

Regarding other government actions to protect the West Branch watershed, the DEP is continuing to monitor bird populations at the reservoir. DEP has recorded seasonal increases in bird activity, but has apparently not yet implemented a bird-deterrent program similar to apparently successful operations at Kensico.[52] DEP also is assessing the function of wetlands in the West Branch watershed and is planning silvicultural work and landscape restoration along the reservoir's shoreline.[53]

The one important exception to government's generally lackluster approach to West Branch watershed protection has been New York City's active land acquisition program there. Significantly (and in contrast with its lack of action in the Kensico watershed), the city's land purchasing program has made the West Branch watershed a top priority. According to DEP's land staff, the city had purchased 1,216 West Branch acres and had an additional 2,654 acres under contract as of October 1998.[54] This is a positive track record, and merits praise. By itself, however, this land program will be unable to protect the entire West Branch watershed from further unsound development.


44. NYCDEP, "West Branch Drainage Basin Report," January 1998, p. 20.

Horse Pound Brook, for example, which contributes less than 1% of total reservoir inflow accounts for about 33% of total and fecal coliform loads. Ibid., p. 17.

45. Ibid., p. 47.

Indeed, DEP's filtration avoidance report to EPA revealed that two recent septic system failures had occurred at commercial establishments in the West Branch watershed. NYCDEP, "Quarterly Report on Enforcement Actions, Volume I," October 1998, pp. 5-6.

46. "West Branch Report," p. 25.

47. "West Branch Report," p. 2.

48. "West Branch Report," p. 36.

49. "West Branch Report," p. 57.

50. Eric Gross, "Putnam's Fastest Growing County in State," The Putnam Courier-Trader, March 26, 1998, p. 3.

51. "West Branch Report," p. 12.

52. "West Branch Report," p. 45.

53. "West Branch Report," pp. 52-53.

54. NYCDEP, " Land Acquisition & Stewardship Program Status Report," October 23, 1998.

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