About half of the land area of Virginia is drained by the creeks, streams and rivers that comprise the Chesapeake Bay watershed, and two-thirds of the state's population lives within the watershed. From the Shenandoah Valley to the Eastern Shore, each Virginian can literally touch the Chesapeake Bay through the network of creeks and streams that cover the area. In an effort to reduce pollution in urban and suburban runoff one of the growing areas of nutrient pollution in the Chesapeake Bay estuary, the 2011 Virginia General Assembly passed SB 1831 that bans phosphorus in most lawn fertilizers and more tightly restricts the use of fertilizer by professional lawn and turf service companies. This bill was supported by the Chesapeake Bay Foundation and the Piedmont Environmental Counsel.
The newly passed law prohibits the sale, distribution and use of lawn maintenance fertilizer containing phosphorus after December 31, 2013 and it will be unlawful to offer for sale any deicing agent containing urea, nitrogen, or phosphorus intended for application on parking lots roadways, and sidewalks, or other paved surfaces. The law also requires golf courses to implement nutrient management plans by July 1, 2017, and will utilize the existing resources of the Soil and Water Conservation Districts and the Department of Conservation and Recreations to provide technical assistance and training and establish a cost-share program to assist in implementation of the nutrient management plans. For homeowners the Department of Agriculture and Consumer Services will develop consumer information and recommended best practices for the application of lawn fertilizer. The law also regulates lawn service companies and establishers reporting requirements for those who apply lawn fertilizer to more than 100 acres of nonagricultural lands annually This effectively leverages the existing resources and expertise to get the most bang for the buck in meeting the Chesapeake Bay TMDL and restoring the Chesapeake Bay estuary and should not impact property owners excessively. Research has shown that most lawns are not deficient in phosphorus and phosphorus free lawn fertilizer is widely available.
The TMDLs were created by a series of models of the Chesapeake Bay Watershed that include various land use models, water quality models and watershed models. These computer models are mathematical representations of the real world that estimate environmental events and conditions. The models are at best imperfect, but they are nonetheless the best tool available to view the 64,000 square miles of the watershed. The Chesapeake Bay and its watershed are so large and complex, that scientists and regulators rely on computer models for critical information about the ecosystem’s characteristics and the impact of various environmental actions to reduce pollution.
Pollutions loads for nitrogen, phosphorus and sediment in the urban areas are calculated using a constant pounds/acre/year for impervious acres as a fixed input, and the pervious load is based on total fertilizer sales data. Reducing the salting of roads, sidewalks and parking lots should impact the load number on impervious acres. Restricting the statewide sales of phosphorus containing fertilizer will reduce the total sales number which represents roughly five percent of excess nitrogen and phosphorus pollution discharged into the Chesapeake Bay from Virginia.
Most lawns are not deficient in phosphorus. Despite the widely accepted myth that phosphate fertilizers will stimulate root growth of transplanted trees and shrubs, research at Washington University has proved this incorrect. Only soils that have been heavily used for agricultural crops or are acid sandy and granitic soils tend to have their phosphorus depleted. In landscaped urban soils, phosphorus is rarely deficient and the misapplication of this element can have negative impacts on the soil environment and the watershed without any benefit to the lawn or plants. Restricting the statewide sale of lawn fertilizer containing phosphorus and educating homeowners about the inappropriate use of lawn fertilizers is a simple way to reduce nitrogen and phosphorus runoff and save consumers a few dollars on unnecessary fertilizer. This could prevent the EPA from implementing stricter stormwater point source limits which was one of “backstop” threats leveled at Virginia if we fail to meet the Chesapeake Bay TMDL goals. This simple step should be all the more effective when the suburban/urban surface portion of the Chesapeake Bay model is revised.