Thursday, June 7, 2012
Sharing Our Water in the Potomac Watershed
The May 1st Potomac Basin Drought Monitor indicated that most (96.8%) of the Potomac River Basin was abnormally dry (D0). Stream flows measured at Point of Rocks and Little Falls were below median levels. Precipitation levels in the Basin were below normal in April by 1.2 inches. Most of the groundwater monitoring wells were normal to low across the Basin. I was not the only one wondering if this would be the beginning of a drought, and worried about my own water supply. Then the rains came.
For the past two weeks as thunder storms have rolled through the region, I checked the water level in the nearby U.S. Geological Survey (USGS) well 49 V1 almost daily and watched as the water level has risen. For two weeks the regular downpours have kept my 15 new trees well watered while the groundwater level has risen 3 feet in the USGS well 49 V1! My drinking water well is undoubtedly as flush as 49 V1 and I’m relieved. The water level has gone from the 10th percentile to the 90th in two fairly wet and stormy weeks. My garden is beautiful, and I can with a clear conscience plan to fill the “gator bags” on my new trees during the dry days of summer. I’ve seen first-hand how immediately rainfall and its percolation into the ground directly impact groundwater.
The groundwater and rain also feed the river at the bottom of my land. That water flows into Bull Run at Sudley Springs and onto the Occoquan River. The rain also feeds the tributaries to the Potomac River. The Washington metropolitan area gets nearly 90% of its drinking water from the Potomac River. The remaining 10% of the region’s supply is from the Patuxent and Occoquan rivers, Goose Creek (a Potomac Tributary that runs through Loudoun County), Lake Manassas (which feeds the Occoquan), the Jennings Randolph and Little Seneca Reservoirs and groundwater resources that serve small community supplies and private wells like mine. Though I fixate on the water resources in my little corner of the region which I have no ability to supplement, the Potomac River is truly the lifeblood of the region. The Potomac is the region’s major source of drinking water, accepts the clean effluent from waste treatment plants, cools power generation plants, and with the C&O Canal, Lake Manassas, and the Occoquan Reservoir provides water recreation and breath taking scenery to our communities.
The Washington Aqueduct Division of the U.S. Army Corps of Engineers (WAD), the Fairfax County Water Authority (FCWA) and the Washington Suburban Sanitary Commission (WSSC) furnish about 95% of the metropolitan region's water. A number of distribution agencies like Prince William Service Authority purchase some or most all of their water wholesale from the big three and distribute that water in their communities. A number of smaller agencies and self-supply portions of distribution agencies supply the remaining 5% of the water.
For more than two centuries the waters of the Potomac seemed unlimited so that the region is not hampered and tied by water allocation agreements created centuries ago that bind many areas of the arid west to fixed and rigid allocations. Instead, the Interstate Commission on the Potomac River Basin, ICPRB, which was authorized by congress in 1940 to address the pollution of the river facilitated the creation of the Potomac River Low Flow Allocation Agreement in 1978 in response to the droughts of the 1960’s and 1970’s. Back in the days when the ICPRB was formed, raw sewage flowed directly into Four Mile Run, Hunting Creek, Hooffs Run, and the Potomac River. The river tributaries were putrid and clogged, a foul mix of bubbling, decomposing human waste in brown waters. Shorelines were devoid of wildlife, and tests showed dozens of disease-causing pathogens. Water pollution was so bad that propeller airplane passengers from D.C. (filled with the members of congress) could look down and see the sludge. The extent of the problem was documented in 1949 by the Izaak Walton League, one of the first conservation organizations in the U.S., in a film showing water conditions in Alexandria.
The ICPRB was one of the first organizations with a congressional mandate to consider water resources on a watershed basis, rather than along political boundaries. However, now, the focus of the ICPRB has changed. Sewage is not released into the Potomac (unless the combined sewer systems in Baltimore or Washington overflow). We have reached the point in population density and development that during times of drought, natural flows on the Potomac are not always sufficient to allow water withdrawals by the utilities (including power generation which takes an awesome amount of water) while still maintaining a minimum flow in the river for sustaining aquatic resources. ICPRB allocates and manages water resources of the river through the management of the jointly owned Jennings Randolph Reservoir (built in 1981), Potomac River Low Flow Allocation Agreement (1978) and the Water Supply Coordination Agreement in 1982 which designated a section of the ICPRB as responsible for allocating water resources during times of low flow. These steps improved reliability of the water supply and ensured maintenance of in-stream flows to meet minimum aquatic habitat requirements as defined by the Maryland Potomac River study in 1981. The section of ICPRB responsible for all this is known as the Section for Cooperative Water Supply Operations on the Potomac (CO-OP), and is formally empowered in its duty by the Water Supply Coordination Agreement of 1982.
This ICPRB is intended to coordinate all the political entities, Maryland, Virginia, Fairfax Water, Washington DC, the federal government and counties and cities within and dependent on the watershed to address the basin’s major challenges, including water quality impairments, water supply and restrictions, flooding, groundwater use, nonpoint source pollution and emerging contaminates. The ICPRB role has been somewhat overshadowed by the recent EPA mandated Chesapeake Bay TMDL, but the ICPRB remains primary in coordinating water supply management and spearheading coordination of effluent water quality issues as they impact drinking water supplies. In their most recent water supply update on June 4th ICPRB assures us that “there is sufficient flow in the Potomac River to meet Washington metropolitan area’s water demands without augmentation from upstream reservoirs.” After the recent rains it appears unlikely that the Washington metropolitan area’s back up water supply- primarily the Jennings Randolph reservoir helped in by the smaller supply at Little Seneca reservoir will be needed during the summer of 2012. ICPRB also brings you the Potomac River Watch.
Thanks to Curtis Dalpra Communications Manager at CO-OP for his help.