Thinking Big On Nutrient Removal
To satisfy increasingly restrictive nutrient discharge requirements, some utilities are taking a holistic, watershed approach to the problem and finding innovative ways to keep water bodies clean. For instance, the Washington Suburban Sanitary Commission (WSSC), a water and sewer agency in Maryland, has focused on protecting its waters through land purchases.
“WSSC has allocated funds in its past two fiscal year budgets for drinking water source protection, focusing on strategic land and/or stream buffer easement purchases,” said WSSC Senior Scientist Martin Chandler.
The latest incarnation of that plan has been WSSC’s contribution toward the purchase of an easement on a local dairy farm.
“WSSC expects that the stream restoration and establishment of the stream buffer will reduce the pollutant load of nutrients — nitrogen and phosphorus — and sediment,” Chandler said.
The land is part of a large agricultural area dotted with residential clusters and its drainage flows into major local tributaries. These lead to one of WSSC’s drinking water supply sources, Triadelphia Reservoir, which has been flagged by Maryland and the U.S. EPA as impaired by nutrient and sediment pollution.
“Degraded streams and stormwater runoff from untreated, impervious surfaces, roads, and farms in the headwaters area add to the pollutant load reaching the reservoir, resulting in gradual loss of storage capacity due to sediment accumulation and algal blooms and possible algal toxins in the water due to over-abundance of nutrients,” said Chandler. “WSSC only has jurisdictional authority over about 6 percent of the land in the watershed draining to its reservoirs. Therefore, partnerships between WSSC and governmental agencies with land use and related authority are critical to addressing sources of pollution.”
WSSC contributed funds to Howard County, which made the land purchase. The county’s stream restoration contractor is still designing the project and construction may not begin for another year. But in the meantime, there will be efforts to accrue monitoring data and define the baseline conditions of the waterway, which can then be compared to data collected after the project is complete.
“Pollutant reductions may not happen instantaneously once the project is completed, but noticeable improvements in water quality are likely to occur within three years of post-construction, allowing time for stabilizing measures to mature. WSSC will assess the water quality outcomes of the project using robust monitoring data.”
While Howard County’s municipal stormwater management permit requires it to restore a certain amount of land with impervious surfaces, there is limited public land in the area on which it can do so. This prompted authorities to look for private partnerships.
“WSSC understands that this project is the first such public-private partnership in the state,” Chandler said. “The outcomes of the project are expected to not only benefit the municipality via stormwater management credits and the landowner whose degraded stream will be stabilized and improved, but also there will be water quality benefits for a public source of drinking water. It is hoped that these water quality benefits will help offset future increases in water treatment costs associated with nutrient pollutions.”
As an innovative approach to controlling nutrients and protecting source water, WSSC plans to keep detailed records of the project so that other utilities may apply similar efforts.
“This project will be fully documented as it proceeds, including a component of environmental education and outreach, so it should provide a resource for other communities seeking assurance that similar approaches would work elsewhere,” said Chandler.
As of now, the benefits of such a program seem obvious and well distributed. Only time will tell how effective it is in protecting drinking water, but it hardly seems like it can hurt.