CORE Massachusetts DepartmentMetadata, citation and of similar papers at core.ac.uk Provided by State Library of Massachusetts Electronic Repository Environmental Management Hydrologic Assessment of the Millers River Prepared By: In Cooperation with: Gomez and Sullivan Executive Office of Engineers & Environmental Affairs, Environmental Scientists Massachusetts Watershed 55 North Stark Highway Initiative, Millers River Weare, NH 03281 Basin Final Report, April 2003 Executive Summary ES1.0 Introduction In 1994, Massachusetts embarked on a new approach to environmental management- the Watershed Initiative. The Watershed Initiative is a broad partnership of state and federal agencies, conservation organizations, businesses, municipal officials and individuals. The Initiative is an innovative, results-oriented program that protects and restores natural resources and ecosystems on a watershed basis. Watershed Teams, such as the Millers River Watershed Team, were created with the goal of understanding watersheds and improving the overall health of the ecosystem. This study was prepared for and funded by the Massachusetts Executive Office of Environmental Affairs, on behalf of the Millers River Watershed Team, as part of the Massachusetts Watershed Initiative. The purpose of this project is to provide a comprehensive assessment of the current and potential impacts that human activities in the Millers River Basin have on flow-dependent natural resources. There are numerous human activities in the Millers River Basin that affect the timing, magnitude, frequency, and rate of change of natural flows in the Millers River and its tributaries including: • public and industrial water supply withdrawals, • wastewater and industrial discharges, • operation of dams such as peaking hydroelectric facilities, or seasonal storage reservoirs such as flood control facilities, and, • long-term land use changes. To support the overall goal of this project, various hydrologic records (water withdrawal records, wastewater discharge records, United States Geological Survey (USGS) streamflow records) were collected and evaluated to understand the magnitude, duration and timing of flow conditions in the Millers River Basin. Once the hydrologic records were evaluated, and the interrelationships between the human activity and regulated streamflow were determined, the resulting potential impacts on natural/biological resources were evaluated. Opportunities exist to improve aquatic habitat in the Millers River Basin by better management of river flow. Even modest modifications toward the natural flow regime (such as maintaining run-of-river operation, flushing flows, ramping rates, and seasonal minimum flows below dams) may result in vast improvements in aquatic habitat conditions in the Millers River. ES2.0 Watershed Description The Millers River watershed is located in north central Massachusetts and southwestern New Hampshire where it is bordered on the east by the Nashua River Basin, the south by the Chicopee River Basin, and on the west by the Connecticut River Basin. Shown in Figure ES2.0-1 is a basin map of the Millers River. Also shown in Figure ES2.0-2 is a nodal diagram showing the key locations of dams, flow gages, and wastewater treatment plant discharges (note this map is not to scale). The Millers, Deerfield, Chicopee and Westfield Rivers are the four major tributaries of Millers River Hydrologic Assessment ES-1 Final Report the Connecticut River in Massachusetts. The Millers River begins at the outlet of Sunset Lake in Ashburnham. The mainstem is joined by the North Branch Millers River at Whitney Pond in Winchendon. From its origins in New Hampshire it flows south and then gradually turns west to the Connecticut River. The Millers River flows for approximately 51 miles, 44 miles of which occur in Massachusetts. The watershed drains a total of 389 square miles (mi2), approximately 310 mi2 of which are in Massachusetts. The major tributaries to the Millers River include the Otter (60.4 mi2) and Tully Rivers (74.0 mi2). Parts or all of the following towns are located in the Massachusetts portion of the basin: Erving, Montague, Wendell, New Salem, Northfield, Warwick, Orange, Royalston, Athol, Petersham, Phillipston, Templeton, Winchendon, Hubbardston, Westminster, Ashburnham, and Gardner. The towns are generally rural and land use in the Massachusetts portion of the watershed is over 81% forested. ES3.0 Dams in the Millers River Basin The Millers River Basin has over 197 dams that are used for various purposes including water supply, hydropower generation, industrial use, fire protection, flood storage, and recreation. Most of the dams were constructed many years ago having provided water and power for the region’s industrial growth. This report evaluated dams on the mainstem of the Millers River, and on larger tributaries including Tully, Otter and the North Branch Millers River. Most of the mainstem dams are equipped with hydropower turbines to produce electricity. In addition to these, there are numerous other dams along the Otter River, Tully River and the smaller tributaries to the Millers River Basin. The US Army Corps of Engineers (Corps) operates two flood control projects in the Millers Basin, Birch Hill Dam on the Millers River in South Royalston and Tully Dam on the East Branch Tully River north of Athol. Mainstem Dams (non-Corps) Most of the mainstem hydroelectric stations are exempt from the Federal Energy Regulatory Commission (FERC) relicensing process. Dam owners (called Licensees) that are under FERC jurisdiction are required to conduct a National Environmental Policy Act (NEPA) analysis to determine the affects of project operations on various resources (aquatic, biological, wildlife, botanical, etc). When FERC grants an exemption, the Licensee must accept the operational conditions (minimum flows, project operating conditions, etc) recommended by the Federal (United States Fish and Wildlife Service, USFWS) and state (Massachusetts Department of Fisheries, Wildlife and Environmental Law Enforcement, MDFWELE) fish and wildlife agencies. For the FERC exempt dams on the Millers River, the federal and state agencies mandated run-of-river operations, whereby reservoir inflow should instantaneously equal reservoir outflow. In addition, for those dams that bypass segments of the river, minimum flow requirements were mandated in the bypass reaches. Although the exempt facilities on the Millers River (except the Birch Hill Dam) are to be operated as run-of-river facilities, an evaluation of year 2000 hourly flow records suggest otherwise. Flow gages below some mainstem dams show flow fluctuations of 50-60 cubic feet per second (cfs) in one day, reflecting store-and-release type operations. At the New Home Dam in Orange, discharges have fluctuated Millers River Hydrologic Assessment ES-2 Final Report up to 80 cfs, twice a day. Trout Unlimited (TU) has brought the pulsing operation at New Home Dam to the regulators’ attention and discussions are ongoing to resolve this issue. Corps Dams (FERC-exempt Projects) To reduce potential flooding, similar to the devastation suffered by communities bordering the Millers River during the November 1927, March 1936 and September 1938 floods, the Corps constructed two flood control facilities in the Millers River Basin. Tully Lake Dam is operated as a seasonal storage reservoir by increasing discharges in the fall to create storage for the spring runoff. Birch Hill Dam, a dry-bed reservoir, also functions to store spring flows. These facilities serve a vital function of providing flood protection; however, operations at these flood control projects result in altering the natural timing, magnitude, frequency and rate of change of flow in the East Branch Tully River and the Millers River (below South Royalston). Changes to the natural flow regime caused by these projects include: a) the seasonal distribution and timing of flows, b) the magnitude of low and high flows, and c) the rate of flow change (as gate changes can occur abruptly over minutes). As of September 2002, the Corps and USFWS are having discussions relative to how the Corps operates both facilities. Discussions have focused on project operations including: a) the magnitude of flow releases for pre-scheduled whitewater races, b) the rate of flow change- ramping rates, and c) maintaining minimum flows. It is recommended that discussions between the agencies and the Corps continue. The goal is to operate the facilities closer to a natural system (establish perhaps seasonal minimum flows, limit the rate of flow change, etc), while still serving the primary purpose of flood control. ES4.0 Current and Projected Water Supplies Six communities in the Millers River Basin are registered and/or permitted under the Massachusetts Water Management Act (WMA) to withdraw1 water either from groundwater wells or surface water reservoirs for public water supplies. In addition, there are four registered/permitted industrial water users, although only two are currently active as of September 2002. Shown in Table ES4.0-1 are the WMA water users and their allowable withdrawal. Table ES4.0-1: Water Management Act: Registered and Permitted Water Withdrawals in the Millers River Basin (>100,000 GPD or 0.1 MGD) Authorized Average Daily Withdrawal in 2000 Name (MGD) Public Water Suppliers Ashburnham Water Department 0.18 Athol Department of Public Works- Water Division 1.04 Gardner Department of Public Works- Water Division 1.69 Orange Water Department 0.93 Templeton