Sunday, May 2, 2010

Ramapo River Watershed Conference: Rockland County's Water Resources

By Katie Lukshis

Ramapo River’s 15th Annual Watershed Conference was held this past Friday at Ramapo College in Mahwah, NJ, featuring an informative array of speakers. According to the Ramapo River Watershed Intermunicipal Council, past conferences have always been well attended, since they are open to the public with a free admission to attract students and other concerned members of the community. The conference this year had a very great turn out for both the morning and afternoon presentations. The wine and cheese reception at the end was made up of a small crowd of presenters and faculty members, but allowed for great conversations.

The conference began with opening words from Ramapo College’s President, Dr. Peter Mercer, Rockland County Executive C. Scott Vanderhoef, and Mahwah Township Mayor Richard Martel. Associate Professor of Geography, Howard Horowitz along with Ramapo River Watershed Keeper and Conference organizer, Geoff Welch followed up with updates on the watershed. Horowitz made an interesting comment about the watershed and why there seems to be very little progress, stating that there is a disconnect between science and public policy. He believes there are more rational approaches to the watershed problems this area faces, and that connection between science and public policy needs to be made in order to accomplish these rational solutions.

One presentation that seemed to stand out in terms of importance was from Paul Heisig, a hydrologist from the USGS New York Water Science Center. Heisig’s presentation, “Rockland County Water-Resources Study: Summary of Findings” was prompted by the concerns over the sustainability of water resources provided by the bedrock aquifer that provides almost 1/3 of the county’s water supply. The study’s purpose carried out by the USGS was to (1) define the hydrogeologic framework of the aquifer, (2) assess conditions within it, and (3) identify other potential sources of water for the county.

Paul Heisig, presenting his findings

An important factor in this study that was outlined in Heisig’s introduction was that the population growth in Rockland County has reached nearly 300,000 people, which severely contributes to significant hydrologic changes over the past 50 years. With population increases come higher demands for water; increases in impervious surfaces such as roads, which ultimately affect ground and surface water quality; and therefore an increase in sanitary sewers, which now serve most areas and discharge wastewater to the Hudson and Ramapo Rivers.

The total water use in 2005 was estimated to be at 12.7 billion gallons, with residential use being 63.5% of that total. The second biggest use of water came as a result of increases of summertime usage, due mostly to lawn watering or other uses that do not go into the sanitary sewer system. The three primary sources of public water supply for the county are (1) fractured sedimentary bedrock aquifer that underlies most of the developed areas of the county, mainly the Newark Basin, (2) alluvial (sand and gravel) aquifers in the Ramapo and Mahwah River Valleys, and (3) surface-water sources such as the Hackensack River at Lake DeForest.

The sedimentary bedrock aquifer underlies the lowland part of the county and while coarsening from east to west, consists of mudstone, sandstone and conglomerate strata. These bedding planes have dipped about 10 degrees towards the northwest instead of forming horizontally, and a characteristic such as this has the potential to influence the flow of groundwater. There are fractures found in the bedrock that run parallel to the bedding planes, and are the major water-bearing zones located in the aquifer.

As far as the health of the aquifer goes, Heisig and his findings have showed that there has not been a continuous downward trend in groundwater levels throughout the whole aquifer; groundwater levels decline on a local basis in response to stresses from production wells, which affect stream flow, annual recharge of the aquifer, and sanitary sewering. The greatest concern in regards to the sustainability of groundwater resources is the aquifer’s response to the annual increase in pumpage during the summer months (May – October). Results from USGS studies have indicated that water levels at one-third of supply wells would approach the depth of the well pump (essentially, the bottom of the well) before October.

As surface water sources are being affected by over-pumping, this leads to a decline in the annual recharge of the aquifer. Factors that affect the recharge totals include precipitation amount, wetland and surface water area, overburden thickness, and impervious surfaces of the area.

In the event that Rockland County’s water-use exceeds what is available to them in underground water levels, there are potential additional water sources to take advantage of. One solution may be to increase current pumpage from the bedrock aquifer, since there is the possibility that there are untapped areas for public supply. Other additional sources include the Ambry Pond Reservoir in the northern part of the county, stormwater retention or reuse, increase flow augmentation to the Ramapo River through releases from the Stony Brook watershed, desalinization of water from the Hudson River, or the indirect use of recycled water.

At the conclusion of Heisig’s presentation, he made it evident that the greatest concern and threat to Rockland County’s water resources was the spike of seasonal groundwater use. The overall health and availability of groundwater resources is largely dependent on the county’s ability to limit water-use during those summer peak-demanding months.

For more information about the Ramapo River Watershed Intermunicipal Council and its partners:

For more information about the project

Katie Lukshis is an undergraduate student at Ramapo College, pursuing a Bachelor of Arts in Environmental Studies. She has worked with Geoff Welch, Ramapo River Watershed Keeper, has volunteered at Camp Hill Farm in Pomona, NY, and has worked as a student aide in the George T. Potter Library since her freshman year. She is graduating in August, and is considering continuing her studies in the Sustainability Studies Masters program at Ramapo.

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