Water Resources in Rockland - Planning in a Changing World


United Water of New York agreed in December of 2006, pursuant to a Public Service Commission order, to increase Rockland County water supply, both in the near term and in the medium term (2015 and beyond). The goal of the near term effort is to bridge the gap between December 2006 peak day capacity of 45.5mgd and the projected peak day demand of 52.6mgd in 2015. A number of steps have been proposed and are in process to meet these demands in the next 6 years. At the same time United Water has initiated a long-term water supply planning process to meet demand in 2015 and beyond.


Problems Meeting Peak Demand

Rockland County projects future demand based on historical demand trends, after removing from the analysis years in which demand is reduced by mandatory or voluntary conservation programs (more...).


United Water New York Long-Term Water Supply Project — Alternatives Considered

Following the December 2006 PSC Order UWNY filed a Project Description in January of 2007 identifying 6 potential long-term sources of increased water supply:

  1. A new reservoir at Ambrey Pond
  2. Desalination of brackish Hudson River water
  3. Additional groundwater supplies
  4. Reuse of wastewater
  5. Increased use of Lake DeForest
  6. Use of the Suffern Quarry.

Subsequent evaluation by UWNY determined that only Ambrey Pond and a Desalination Plant on the Hudson were viable long term water supply projects and in September of 2007 UWNY filed a preliminary conceptual design for the Hudson Desalination plant as the recommended Long Term Water Supply Project.

On September 26, 2008 UWNY released a Draft Environmental Impact Statement(DEIS) for the proposed Hudson River Desal Plant now named the Haverstraw Water Supply Project. At the time UWNY noted "Because a lead agency has not been established, this document has not been determined to be 'adequate for public review' by a lead agency pursuant to 6 NYCRR § 617.9(a)(3)."

Once the document is considered adequate for public review, a Notice of Completion and request for public comment will be published by the lead agency. The publication of the Notice of Completion starts the public comment period." 

The alternatives evaluated in the pre-DEIS include all the alternatives above as well as 4 additional alternatives:

  1. No Action
  2. Ramapo River High Flow Skimming with Off Stream Storage
  3. Hudson River Skimming
  4. Combination of Alternatives

In addition to the Hudson River Desal plant only Ambrey Pond and Wastewater Reuse were found to meet the purpose and need for the project because they are judged to be able to provide a reliable and sustainable long-term water source for Rockland County. Wastewater Reuse was rejected because of anticipated public rejection of the use of treated wastewater for drinking. Ambrey Pond was rejected because of the ultimate capacity, the time required to complete the project, and a range of adverse local impacts.


New York State DEC has been established as the Lead Agency for State Environmental Quality Review of the proposed Long Term Water Supply Project

On June 29, 2009 DEC released its Final Scoping Document for a Draft Environmental Impact Statement (DEIS) for the United Water New York Haverstraw Water Supply Project. DEC has preliminarily identified significant environmental issues including but not limited to:

  • Water quality in the reach of the Hudson River where the intake is proposed
  • Water supply allocation including cross-basin transport
  • Energy demands of pretreatment, desalination and treatment technologies, including greenhouse gas and climate change implications
  • Comparison of impacts and viability of possible alternatives to desalination including demand reduction
The Final Scoping Document consists of the outline released on June 29th which follows the chapter sequence of UWNY's preliminary draft EIS and the full draft EIS itself.

Short-Term Water Supply Program and Related Improvements

While most of the attention in Rockland County has been on United Water's long-term plan with its recommended alternative of a desalination plant on the Hudson River at Haverstraw, average and peak day demands until at least 2015 will be met by United Water New York's short-term water supply program and related improvements.

Some short-term actions have been completed already:

  1. Letchworth Water Treatment Plant: update and expansion has added 2mgd additional peak capacity, with no impact on safe yield.
  1. Sparkill well field: Construction of air stripping towers to gasoline contaminated wells has added an additional 0.4mgd in peak capacity in 2008 with another 0.15mgd expected in 2009.

"Safe Yield" has traditionally been defined as the amount of groundwater that can be pumped annually without drawing down aquifer levels because it is equal to annual recharge over the long term. This traditional definition does not include the concept of groundwater-fed surface water sources or groundwater-dependent ecosystems.


Some short-term actions are being evaluated for feasibility:

1. Creating new wells and purchase of existing private wells, including potential wells at Rockland Psychiatric Center, the former St. Agatha Home and Helen Hayes Hospital. Cumulative peak capacity increase could be 1-1.5mgd, with marginal increase in safe yield.

2. Aquifer Storage and Recovery. This action involves pumping water into existing aquifers for storage and use later. If feasible, this is likely to provide more value as a way to Rocklandwater_htmlsincrease flexibility, although a nominal increase in peaking capacity may also be realized (potentially up to 0.5 mgd).

3. Potake Pond Diversion. During dry conditions, United Water is permitted to use water from Potake Pond to prevent the Ramapo River levels from becoming too low. This also allows UW to pump more from the Ramapo wells near the river. The amount of water in Potake Pond available for use is currently being studied and the environmental and hydrological impacts of this change are being evaluated. 

This change would increase UW's flexibility, but would not increase the total safe yield of the system. The use of additional storage in Potake Pond would increase peaking capacity and further extend the period when United Water is able to use the Ramapo Valley Well Field, increasing the flexibility of the United Water system to meet demand during dry conditions. It would not, however, add to the safe yield of the system."

4. Lake DeForest Spill Skimming. When Lake DeForest is full, water passes over the dam; this plan allow usage of this water instead of water that would otherwise have been drawn from wells.  This additional supply would only be available under wet conditions and would therefore not increase the safe yield of Lake DeForest., Nonetheless, this plan would allow existing groundwater wells to be maintained at higher levels, thereby increasing their reliability allowing them to retain their capacity for peak demand periods.


Additional Activities Underway to Improve Rockland County's Water Supply in the Short-Term

1. Reduction of Water Used for Water Treatment

2. Underground Infrastructure Renewal Program. To reduce leakage, United Water has an ongoing program of system-wide replacement of aging water mains, fire flow improvements, and transmission improvements. According to American Water Works Association benchmarks United Water's leakage in Rockland County is in line with that of well-run water distribution systems in the US.

3. Water Conservation Programs. While United Water can't mandate conservation measures and is thereby limited in its ability to depend on conservation as a quantifiable component of a long-term water supply program, it has taken some steps to encourage water conservation and to educate its customers on the importance of water conservation. (more...)


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