Nutrient Management
Aquatic Plants and Nutrient Management
Aquatic plant production is the largest sector of Maryland's aquaculture industry with annual sales over $2 million. Several hundred plant species or varieties are cultured and sold primarily as ornamentals for the expanding water garden industry. Many of these shallow water species such as arrow arum, arrowhead, bulrush, duck potato, iris, pickerelweed, and rushes are also used for restoration or mitigation projects for planting in the littoral zones of stormwater or wetland ponds. The importance of aquatic plants in absorbing nutrients and trapping sediments is widely recognized by resource managers in water treatment ponds or constructed wetlands and in agricultural settings for treating livestock wastes. In most urban watersheds, stormwater ponds serve as the primary treatment method for mitigating housing and commercial nutrient and sediment runoff. The Chesapeake 2000 Agreement specifically states that improvements in stormwater performance are needed to meet its goal of deceased nutrient loading to the Bay by 2010. The potential application of aquatic plants for nutrient management in stormwater ponds is extensive since they are used throughout Maryland, with over 17,700 ponds accounting for 175,720 acres in 16 Maryland counties alone. They are also widely used throughout the Chesapeake Bay watershed and United States.
Despite the broad understanding and published recommendations of the value of aquatic plants in nutrient uptake, specific uptake potential has only been identified for a few of these plant species. Our research is aimed at determining the effectiveness of numerous marginal plant species for nitrogen and phosphorus uptake and evaluating various applications of aquatic plants for enhancement of nutrient capture within stormwater and other treatment settings.
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Stormwater Pond Enhancement and Management
Stormwater ponds have become a familiar sight in housing developments and suburban communities. Maryland alone has approximately 18,000 wet stormwater ponds that cover nearly 200,000 acres. The primary function of these ponds is to capture and treat runoff –– the excess water from the surrounding area that is not absorbed directly into the ground during rain and storm events. This water can carry with it high amounts of nutrients and pollutants. Stormwater ponds are often edged with some variety of aquatic plant, which can absorb excess nutrients before they become bound to organic material in the soil.
Beyond nutrient reduction, stormwater ponds can serve as valuable habitat for local wildlife, including fish, frogs, turtles, birds and waterfowl. Such a productive ecosystem beautifies the neighborhood, providing a valuable resource for the entire community.
But proper management of stormwater ponds is crucial. If poorly managed, stormwater ponds can suffer from the overgrowth of algae or invasive plants, such as Phragmites, which detracts from their function for nutrient capture and aesthetic appeal. For this reason, wet ponds have fallen from favor for stormwater treatment options in new development. Follow the links below and download our Extension Brief to learn how to better manage the tens of thousands of existing ponds, helping to optimize their role in nutrient capture and community aesthetics.
http://www.mdsg.umd.edu/programs/extension/water_quality/stormwater_ponds/