The Plight of Aging Dams, and One Solution

As dams age, the danger to life and property around them increases. If they were to suddenly fail and flood downstream communities and infrastructure, there would be serious loss of property and life. More and more, dam removal has become the best option for property owners who no longer want or can no longer afford the rising cost of maintenance and repair work required to maintain such a complex structure.

The Courier-Post recently published this Commentary piece titled, “The Plight of Aging Dams, and One Solution”, which was written by Princeton Hydro’s Vice President and Principal Engineer Geoffrey M. Goll:

Many of our nation’s dams, while originally intended to provide benefits for mills, water supply and energy generation, are severely aged and unmaintained. Nearly 20,000 of the dams on the Army Corps of Engineers’ National Inventory of Dams – which doesn’t even include many dams that are not inventoried or known about – were built in the 1960s. With expected lifespans of 50 years, these dams have reached their limit. And by 2020, 70 percent of all dams will be over 50 years old. Like roads and bridges, dams also require upkeep, maintenance and eventually removal or rehabilitation.

As dams age, the danger to life and property around them increases. If they were to suddenly fail and flood downstream communities and infrastructure, there would be loss of property and life. The Association of State Dam Safety Officials, the professional organization for dam safety engineering professionals and regulators, estimates there would need to be a $21 billion investment to repair just 2,000 deficient, high-hazard dams. More and more, the removal of dams has become an option for owners who no longer want or no longer can afford the rising cost of maintenance and repair work required to maintain such a complex structure.

For dams like this, removal benefits local economies, and eliminates threats to people and property in local communities. There are also many byproduct benefits, including restoring fish migration routes, improving water quality, restoring floodplain functions and values, and increasing biodiversity.

On Sept. 8, we had the honor of meeting the Secretary of the Interior Sally Jewell during a visit of our Hughesville Dam removal project on the Musconetcong River, located in northwestern New Jersey. This project exemplifies the successes that can be achieved through public-private partnerships, including local communities, state and federal agencies, nongovernmental organizations, and private commercial entities. This is the fifth dam removed on the Musconetcong River by a coalition of stakeholders, led by the Musconetcong Watershed Association. The Department of the Interior (specifically, the U.S. Fish and Wildlife Service) provided funding to remove this very old, out-of-compliance dam.

The success of these partnerships is due to the unique strengths that each organization brings to the table. This project achieved the removal of a flood and safety hazard, and will restore additional river miles for migratory fish, improve water quality by removing the heat sink of the reservoir, and provide additional safe passage for recreation along the river.

It is easy to see why Secretary Jewell chose this site to visit, but the old and outdated dam at Hughesville is far from alone. Across the nation, we need to remove dams like this at a much larger scale – aging dams that no longer are of value to us, but increase the danger to those who live downstream. If we can build on this momentum and start to address the issue of dam safety compliance on a national scale, we can address these threats to American’s safety and strengthen local economies.

Lake Management and Restoration in the Hudson River Valley

Lake Management Planning in Action
at Sleepy Hollow Lake and Truesdale Lake

The Hudson River Valley encompasses 7,228 square miles along the eastern edge of New York State. It comprises 3 million residents, 133 communities and 553 significant freshwater lakes, ponds and reservoirs. Princeton Hydro has worked with municipalities and organizations in the Hudson River Valley for over 18 years actively restoring, protecting and managing waterbodies throughout the area.

Princeton Hydro is currently implementing customized Lake Management Plans at two waterbodies in the Hudson River Valley: Sleepy Hollow Lake, a 324-acre drinking water reservoir/recreational lake located in Green County, NY and Truesdale Lake, an 83-acre lake in Northern Westchester County, NY.

Sleepy Hollow Lake

Stretching over two and a half miles long and reaching depths of approximately 70 feet, Sleepy Hollow Lake is a NYSDEC Class “A” drinking water reservoir that provides potable water for the Sleepy Hollow community. The lake is also extensively used by residents for swimming, boating and water-skiing. And, it is recognized as an outstanding large-mouth bass and white crappie (current New York State record holder) fishery!

Princeton Hydro was hired by the Association of Property Owners (APO) at Sleepy Hollow Lake to develop a comprehensive lake management plan. The first step involved an in-depth analysis of the biological, chemical and physical attributes of the lake, with the goal being to generate a database that can be used to better understand the interactions defining the Sleepy Hollow Lake ecosystem.

The data collection and investigation phase includes:

  • Watershed Investigation: an in-depth assessment of the major and minor tributaries and road network in order to identify areas of stream bank and ditch erosion; sources of both sediment and nutrient loading to the lake
  • Bathymetric Survey: the accurate mapping of water depths and the quantification of the amount of accumulated, unconsolidated sediment present in the lake
  • Fisheries & Food Web Study: the collection of fish and plankton data for the purpose of creating a comprehensive fisheries management program focused on managing the lake’s outstanding fishery, further promoting the ecological balance of the lake, and enhancing lake water quality
  • Aquatic Plant Mapping: the development of detailed maps identifying the plant species present in the lake along with their relative abundance and distribution throughout the lake, but especially within the shallower coves
  • Hydrologic & Pollutant Budget: the computation of the lake’s hydrologic budget and pollutant loading budget. The hydrologic budget represents the water balance of the lake and is an estimate of all of the inputs and losses of water. The pollutant budget represents an estimate of the amount of nitrogen and phosphorus entering the lake from various sources. These data are used to evaluate the effectiveness of lake management options, enabling us to determine the best, most ecologically sound and most cost-effective approach to protect and improve the lake’s water quality now and into the future.

Princeton Hydro is now in the process of utilizing all of the data developed during the investigation phase of the project to create a comprehensive Lake Management Plan that will be used to guide the APO’s future lake restoration and protection initiatives. The Lake Management Plan and supporting data will also be used by Princeton Hydro on behalf of the APO to seek grant funding for various lake and watershed restoration projects.

Princeton Hydro is also overseeing the aquatic plant management program at Sleepy Hollow Lake, the focus of which is to control invasive plant species in a manner consistent with and complimentary of the lake’s overall ecological enhancement.

Truesdale Lake

At Truesdale Lake, Princeton Hydro is working with the Truesdale Lake Property Owners Association (TLPOA) to develop a comprehensive Lake Management Plan. The Plan provides a detailed project implementation roadmap for TLPOA, including recommendations for priority ranking of particular activities and restoration measures. A key element of the Plan are the short-term (1-year) and long-term (5-year) water quality and problematic algae and invasive aquatic plant control goals. Another highlight of the Plan is the review of Federal, State, County and local grants, programs and initiatives that may provide funding for identified lake and watershed projects.

During the Plan’s development, Princeton Hydro has provided the TLPOA with lake management consultation services such as community education initiatives, the coordination of NYSDEC permitting activities associated with the implementation of lake restoration measures, and the oversight and administration of an aquatic weed management program at the lake.

Earlier this year, Truesdale Lake experienced excessive aquatic weed growth, which significantly reduced the water quality, recreational use and aesthetics of the lake. Princeton Hydro utilized its Truxor, an eco-friendly, amphibious machine, to cut and remove the nuisance weed growth from the lake. This program helped reduce the negative impacts to the lake and lake users caused by the dense weed growth. Future use of the Truxor to remove invasive weeds is already part of the long-term Lake Management Plan for TLPOA. The Truxor will be used in concert with other measures to control invasive weed growth and restore a more balanced native aquatic plant community.

For more information about Princeton Hydro’s work in the Hudson River Valley or to discuss your project goals, please contact us.