Forest Conservation and Management in The
Total Page:16
File Type:pdf, Size:1020Kb
Climate Change Effects on Forests, Water Resources, and Communities of the Delaware River Basin Abstract: The Delaware River provides drinking water to 5 per- cent of the United States, or approximately 16.2 million people Will Price living in 4 states, 42 counties, and over 800 municipalities. Director of Conservation The more than 1.5 billion gallons withdrawn or diverted daily Programs, Pinchot Institute for drinking water is delivered by more than 140 purveyors, yet for Conservation, Washington, constitutes less than 20 percent of the average daily withdraw- DC als. Approximately 64 percent of the water withdrawal is used for thermoelectric cooling, a primarily non-consumptive use. Susan Beecher The main stem of the Delaware River is free-flowing, such that permitted water withdrawal and discharge depends on weath- Research Fellow, Pinchot er-related flow conditions. Low flows can limit power gen- Institute for Conservation, eration based on in-stream temperature limits, and can also Washington, DC result in the salt line reaching water intakes in the 133 mile tidally-influenced portion of the river. High flows can damage facilities and cause exceedance of drinking water standards. Source water areas of the Delaware River Basin (DRB) are primarily forested (>75 percent), accounting for the relatively high existing water quality, and contributing to attenuation and reduction of flows. These areas are predominantly in pri- vate ownership, and in recent years have been among the ar- eas of the Basin experiencing the fastest population growth. Development of private lands and associated changes in forest cover, impervious surface and floodplain encroachment are of concern. Modeled climate-related changes in timing, type, and intensity of precipitation are also concerns. The diversity in types of water use within the DRB corresponds with a variety of types of risk imposed by changes in climate and land cover. Common Waters, a partnership of close to fifty organizations is piloting strategies to avoid and adapt to changes affecting forests and water resources that are predicted to occur with climate change. This paper discusses predicted climate chang- es for the Delaware River Basin and what they imply for the importance of forests and water resources, and presents two case studies: a source water protection program for landown- ers and a climate adaptation plan for the Upper Delaware River Basin. These efforts in the Delaware River Basin could be models for watersheds with highly diverse types of use and complex regulatory systems. INTRODUCTION The mainstem Delaware is the longest undammed river east of the Mississippi, flowing freely for 330 miles from USDA Forest Service RMRS-P-71. 2014. 379 southern New York (2,362 square miles or 18.5 percent of the basin’s total land area), through eastern Pennsylvania (6,422 square miles or 50.3 percent), New Jersey (2,969 square miles, or 23.3 percent), and Delaware (1,004 square miles, or 7.9 percent) to the Atlantic Ocean. The Delaware River’s 13,539 square mile watershed drains only about 0.4 percent percent of the United States land area yet supplies drinking water to 5 percent of the U.S. population—some 16 million people in four states. The Basin also supports the largest freshwater port in the world within the 782 square mile Delaware Bay. Three reaches of the Delaware River, about three- quarters of the non-tidal River, are included in the National Wild and Scenic Rivers System (Kauffman 2011). In 2010, over 8.2 million residents lived in the basin including 654,000 people in Delaware, 2,300 in Maryland, 1,964,000 in New Jersey, 131,000 in New York, and 5,469,000 in Pennsylvania. An additional 8 million people in New York City and northern New Jersey receive their drink- ing water through interbasin transfers from Upper Delaware River reservoirs. Between 2000 and 2010, the population in the Delaware Basin increased by 6.1 percent. Over the last decade, a number of counties in the basin showed double-digit population increases and Philadelphia gained population for the first time in centuries (Kauffman 2011). WATER USE AND MANAGEMENT IN THE DELAWARE RIVER BASIN In the Delaware River Basin, as in many river systems around the world, water is put to an as- tounding number of uses. In some ways the mainstem Delaware River is unique for its size in that it is the longest free-flowing river east of the Mississippi. Flows from upper tributaries are partially controlled by dams, holding back 238 billion gallons in two reservoirs supplying the city of New York, for an average daily detention and diversion of 665 million gallons. The re- maining 90 percent (land area) of the watershed downstream of the NYC reservoirs is controlled by the weather, and serves the needs of another 7 million people. Approximately 64 percent of the 8.6 billion gallons withdrawn daily from the Delaware River is used for thermoelectric cooling. Typically Less than 5 percent of cooling water is actually consumed; the rest is discharged back into the basin. Less than 20 percent is used for drinking water—an average approximately 665 million gallons allowed for diversions to the city of New York and New Jersey and the rest (860 million gallons per day) for residents throughout the re- gion, many of whom live outside the basin’s boundaries. In recent years per capita water consumption has declined with increased efficiency in all sec- tors, and declining productivity associated with the economic downturn. Declines in water consumption are offset to some extent by increased deployment of closed-cycle cooling (CCC) for electricity generation. This type of cooling reduces total water withdrawn, but increases wa- ter consumption as more water is lost from closed cycle systems. Despite improved efficiency, a projected increase in population within the Delaware River Basin is predicted to result in a gradual increase in total water consumption for drinking water, industrial processes, and energy generation (DRBC 2012). A recent study estimates the annual regional economic value of water supply at $25 billion (Kauffman 2011). Estimates in this study do not include the embodied water content and en- ergy in and goods and services exported to the world from the New York, Philadelphia, and 380 USDA Forest Service RMRS-P-71. 2014. Wilmington corridor—a region containing the 1st and 6th most populous metropolitan areas in the United States. That the entire main stem of the river is free-flowing and is principally managed by the storage and release of water in the very upper reaches of the watershed, with implications for the an- nual water availability to New York, makes the system vulnerable to weather extremes. Periods of low flow can have several interrelated effects. Drought conditions became the first test of the federal compact between New York, New Jersey, Delaware, and Pennsylvania and resulted in a 1978 “Good Faith Agreement” developed and implemented by the Delaware River Basin Commission, and designed to protect aquatic life by maintaining minimum flows through res- ervoir releases (DRBC 2013; Albert 1987). Drought conditions and extended periods of low flow pose many other problems for water use in the basin, not the least of which is allocation for drinking water and energy generation. Energy generation—the largest category of water withdrawal—is limited by temperature requirements set for the river downstream of facilities. The Schyukill Restoration Fund in the Schyukill River watershed (a major river flowing into the Delaware River) was created through an agreement that also includes augmentation of “pass-by flows” for a nuclear generation station, which had at times exceeded temperature limits. Perhaps one of the biggest problems posed by low flows is the upstream movement of the “salt- line.” The Delaware River has the largest freshwater tidal prism in the world, as the Delaware Bay’s depth and “cone-shaped geometry” allows for more than 100 miles of tidal exchange upriver. Freshwater flows normally impede tidal advance. However, low flows can allow high chloride levels (>250 ppm) to reach drinking water and cooling intakes within the tidally influ- enced portion. Floods are also a concern in the Delaware River Basin, especially the potential for lower basin flooding resulting from a combination of coastal storm surge and floodwaters from upstream—a scenario that was narrowly missed during Hurricane Sandy in 2012, which still devastated lower portions of the basin. Prior serious flooding in 2004 and 2006 led to the development of a Flexible Flow Management Program (FFMP) which balances drinking water needs for New York and the rest of the basin, energy generation, ecological requirements, and upstream movement of the salt-line (Gong 2010). Climate changes affecting water quality and quantity in the Delaware River Basin Changing climatic conditions are already being felt in the Upper Delaware region. Both annual mean temperature and annual mean precipitation in the upper basin have increased significantly over the past 100 years. The trend over the past 30 years for temperature and precipitation is more than 3 and 5 times the 100-year trend, respectively. The number of days per year with heavy precipitation shows a significant upward trend. Future projections generally show the basin getting progressively warmer and wetter throughout the 21st century (Najjar and others 2012). Higher average temperatures, increased magnitude and frequency of heavy precipitation events, a longer growing season, warmer winters with more precipitation falling as rain, and changing hydrologic conditions all put multiple sectors at risk, including forests, water resourc- es, agriculture and human health. Information on how these projected trends could affect water quality and quantity of the Delaware River is only beginning to emerge as global climate change models are downscaled to the region, and interpreted for the watershed.