Burden Pond Dam on the Wynants Kill Creek of New York
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Technical Report Assessment of Sediments Impounded by the Burden Pond Dam on the Wynants Kill Creek of New York Submitted to New York State Water Resources Institute (WRI) at Cornell University and New York State Department of Environmental Conservation (DEC), Hudson River Estuary Program for the project “Assessment of Sediment Properties in the Impoundment of an Aged Dam in the Hudson River Watershed” Prepared by Weiming Wu and Ian Knack Department of Civil and Environmental Engineering Clarkson University Box 5710, 8 Clarkson Avenue Potsdam, NY 13699, U.S.A. March 31, 2016 Summary Burden Pond Dam is a small old dam located on the Wynants Kill Creek, a tributary of the Lower Hudson River in New York. For safety concern and to connect the upstream and downstream aquatic habitats, removal of this dam may be considered as one of the management plans. The present project aimed to assess the quantity and quality of sediments filled in the impoundment of Burden Pond Dam. Cross-sections were surveyed and sediment core and grab samples were collected, to quantify the sediment deposit amount and analyze the deposit size compositions and the associated chemicals. The data show that the lake sediments consist of gravels and sands in the upper end of the lake, and sand, silt and clay in the area close to the dam. It is estimated that about 28.8 acre-feet sediment deposits will likely be eroded and transported to the downstream if the dam is removed or failed. PCBs and pesticides are not abundant in the lake sediments. However, the lake sediments are enriched with nitrogen and phosphorus, as well as metals including Al (Aluminum), K (Potassium), Mg (Magnesium), Mn (Manganese), Ba (Barium) and Fe (Iron). These data and results are useful for the dam removal feasibility and impact studies in terms of the potential hazards the sediments may pose if reintroduced into the environment. 1 Acknowledgements This project was supported by NYS Water Resource Institute (WRI) at Cornell University and New York State Department of Environmental Conservation (NYS DEC), Hudson River Estuary Program. Clarkson University waivered the indirect costs associated with this project. City of Troy is acknowledged for allowing us to use the Burden Pond Dam as the study site. Mr. Nick Davis at City of Troy Engineering Department is highly appreciated for his help for the field work. NYS DEC and WRI officials Andrew Meyer, Andrew Donovan, Scott W. Cuppett and Christina Tonitto are acknowledged for their kind comments and suggestions for this project, and helping us to find the study site. Dr. Thomas Holsen and Dr. Philip K. Hopke, Professors at Clarkson University, helped analyze the chemicals on the sediment samples. 2 Table of Contents Chapter 1 – Introduction 4 1.1 Problem Statement 4 1.2 Objective of the Project 4 1.3 Project Team and Student Training 4 1.4 Arrangement of This Report 5 Chapter 2 – Background Information of the Burden Pond Dam 6 2.1 Geomorphological Information 6 2.2 Potential Hazards 7 2.3 Water Quality and Ecosystems 8 2.4 Socio-economics 9 Chapter 3 – Field Surveying and Sampling 11 3.1 Field Surveying of Cross-Section Bathymetry 11 3.2 Sediment Sampling 14 3.3 Geomorphological Features of the Pond and Its Upstream and Downstream Channels 18 Chapter 4 – Size Compositions of the Pond Sediments 28 Chapter 5 – Chemicals Absorbed with the Pond Sediments 34 5.1 Nitrogen and Phosphorus 34 5.2 Mercury 35 5.3 PCBs and Pesticides 36 5.4 Toxic Metals 39 Chapter 6 – Possible Sediment Erosion upon Dam Removal 57 6.1 Sediment Erosion Layer Thickness 57 6.2 Evolution of Cross Sections 59 6.3 Sediment Erosion Volume 64 Chapter 7 – Conclusions 66 References 68 Appendix A – Data of Sediment Size Compositions 69 Appendix B – Bathymetry Data of Cross Sections 76 3 Chapter 1. Introduction 1.1 Problem Statement In the last centuries, particularly since 1940s, the U. S. has built a large number of dams for flood control, power generation, water supply, recreation and so on. There are over 5,500 dams in New York State. Some of these dams have reached their design life. Because of population growth and land-use changes through time, the impoundments are filling up with sediments, some structural components have deteriorated, safety regulations are stricter, and the hazard classification has changed for some dams (Bennett and Cooper, 2000). The Burden Pond Dam on the Wynants Kill Creek is one of such aged dams. There is an increasing focus on decommission and removal of older dams, to reduce the flood risk imposed by them and connect the aquatic habitats downstream and upstream (Alderson and Rosman, 2014). However, before any rehabilitation strategy is designed and implemented, the quantity and quality of the sediments impounded by those dams should be assessed to determine the potential hazards if the sediments are reintroduced into the environment. 1.2 Objective of the Project The objective of the present project was to conduct field campaign and laboratory analysis to investigate the quantity and quality of sediments deposited in the reservoir of Burden Pond Dam. The deposited sediment volume and size compositions were measured. The chemicals, such as nutrients, heavy metals (e.g., mercury, chromium, cadmium, zinc), and PCBs/pesticides, absorbed on the fine sediments were analyzed. The collected data and derived results can be used for the future studies on the feasibility of removing the dam and the potential impacts on the downstream stream water quality and habitats. 1.3 Project Team and Student Training The project PI was Dr. Weiming Wu and Co-PI was Dr. Ian Knack, Professors at Clarkson University. Mr. Chamil Perera, Ms. Zahra Sharifnezhadazizi, and Mr. Brandon Teetsel, graduate students at Clarkson University, participated in the field work and sediment size composition analysis. Miss Amina Grant, a Penn State undergraduate student supported by a NSF-funded REU (Research Experience for Undergraduate) project at Clarkson University, also participated in this project during the summer 2015. The above three graduate students and one REU undergraduate student were trained by participating in this project and conducting the field survey, sediment sampling, laboratory analysis, presentation and report writing. 4 1.4 Arrangement of This Report This report consists of seven chapters and two appendices. Chapter 1 introduces the general information of this project. Chapter 2 describes the background information of the Burden Pond Dam and the Wynants Kill Creek watershed. Chapter 3 introduces the field campaign conducted by the project team during July 21-23, 2015. Chapter 4 presents the laboratory analysis of the size compositions of the pond sediments. Chapter 5 presents the laboratory analysis of chemicals in the sediment samples. Chapter 6 presents the estimate of sediment amount that will be possibly eroded from the pond if the dam is removed. Chapter 7 gives conclusions from this project. Appendix A tabulates the sediment size composition data, and Appendix B gives the cross-section bathymetry data. 5 Chapter 2. Background Information of the Burden Pond Dam Existing information and historical records on the study dam and adjacent areas were collected by consulting with the dam owner, Troy Water Authority agencies, NYS DEC, and so on. A NSF-sponsored REU (Research Experience for Undergraduate) student Miss Amina Grant conducted this task, supervised by Dr. Weiming Wu. The preliminary findings are summarized below. 2.1 Geomorphological Information Burden Pond Dam is a small, old dam on the Wynants Kill Creek, a tributary of the Lower Hudson River (Fig. 2.1). It is located in Rensselaer County of Troy, New York. The dam is 17 feet high and 160 feet in length. The dam was constructed from masonry or stonework (Figure 2). Burden Pond was completed in 1942. The dam had a normal surface area of 19 acres. Its capacity was 153 acre-feet and drains an area of 34 square miles. Now the reservoir has been completely filled with sediments. The City of Troy owns the Burden Pond Dam while the New York State Department of Environmental Conservation (NYS DEC) regulates it. Currently, the dam is being used for recreational purposes. Fig. 2.1. Map of the Burden Pond on the Wynants Kill River, a tributary of the Lower Hudson River The Wynants Kill Creek is just 14.1 miles long, but it falls some 850 feet, notably down the steps of three shale overthrusts, each providing many excellent sites for the development of waterpower (Harris and DeBlois, 2005). From its headwaters at Crooked Lake in the Town of Sand Lake, the Wynants Kill Creek runs through the towns of Poestenkill and North Greenbush before falling over a series of waterfalls and dumping into the Hudson River at Troy. During that 6 journey, it passes through the villages of West Sand Lake and Wynants Kill, and Troy's Albia and South Troy neighborhoods (Benjamin, 2013). Fig. 2.2. Photo of Burden Pond Dam 2.2 Potential Hazards Burden Pond Dam is of low hazardous potential. Hazard potential is used to classify a dam according to the potential impact a dam failure or misoperation would have on the upstream or downstream areas or at locations remote from the dam (FEMA, 2004). Low hazardous potential is defined as dams that fail will result in no probable loss of human life and low economic and environmental losses (FEMA, 2004). Losses are principally limited to the owner’s property (FEMA, 2004). Even though its low hazardous potential, its failure or removal may cause sediment and debris washed downstream and affect the downstream channels. It is unknown whether any contaminant is associated with the lake sediments. Therefore, the quantity and quality of the lake sediments is a question to be answered.