Water Quality Functions of Riparian Forest Buffers in Chesapeake Bay Watersheds

Abstract

/ Maryland, Virginia, and Pennsylvania, USA, have agreed to reduce nutrient loadings to Chesapeake Bay by 40% by the year 2000. This requires control of nonpoint sources of nutrients, much of which comes from agriculture. Riparian forest buffer systems (RFBS) provide effective control of nonpoint source (NPS) pollution in some types of agricultural watersheds. Control of NPS pollution is dependent on the type of pollutant and the hydrologic connection between pollution sources, the RFBS, and the stream. Water quality improvements are most likely in areas of where most of the excess precipitation moves across, in, or near the root zone of the RFBS. In areas such as the Inner Coastal Plain and Piedmont watersheds with thin soils, RFBS should retain 50%-90% of the total loading of nitrate in shallow groundwater, sediment in surface runoff, and total N in both surface runoff and groundwater. Retention of phosphorus is generally much less. In regions with deeper soils and/or greater regional groundwater recharge (such as parts of the Piedmont and the Valley and Ridge), RFBS water quality improvements are probably much less. The expected levels of pollutant control by RFBS are identified for each of nine physiographic provinces of the Chesapeake Bay Watershed. Issues related to of establishment, sustainability, and management are also discussed.Research is sometimes applied to broad-scale environmental issues with inadequate knowledge or incomplete understanding. Public policies to encourage or require landscape management techniques such as riparian (streamside) management will often need to proceed with best professional judgment decisions based on incomplete understanding.Riparian forest buffer systems (RFBS) are streamside ecosystems managed for the enhancement of water quality through control of nonpoint source pollution (NPS) and protection of the stream environment. The use of riparian management zones is relatively well established as a best management practice (BMP) for water quality improvement in forestry practices (Comer-

Heuristic Models for Material Discharge from Landscapes with Riparian Buffers

“…Many studies have considered how width affects material concentration in water traversing a single transect through a buffer (see review in Lowrance et al 1997). However, we are aware of no published studies that have quantified the distribution in buffer widths across a landscape or determined the effects on watershed discharge of among-watershed variations in the buffer distribution.…”

“…Buffers can also retain materials from other sources (Chescheir et al 1991, Schellinger and Clausen 1992, Hanson et al 1994, Bren 1995. With effective retention, small areas of riparian buffer can greatly reduce land discharges of nutrients to aquatic systems (Jordan et al 1986), so there has been strong interest in managing riparian systems to reduce nonpoint-source water pollution (Lowrance et al 1985, Correll 1997, Haycock et al 1997, Lowrance et al 1997.…”

Benefits of riparian forest for the aquatic ecosystem assessed at a large geographic scale

“…Such benefits may include the following: addition of organic matter, diversifying the trophic conditions; thermal regulation by forest canopy cover; structuring of habitat and provision of microhabitat; and buffer for nutrients and pollutant influx to the water course (Lowrance et al, 1984;Lowrance et al, 1997;Wenger et al, 1999). These functions have been evidenced only from local studies with field measurements (Storey and Cowley, 1997;Wallace et al, 1997;Parkyn et al, 2003;Dodds and Oakes, 2006;Rios and Bailey, 2006) and from some larger scale studies in strictly agricultural watersheds (Stewart et al, 2001;Wilson et al, 2008;Arnaiz et al, 2011).…”

Retenção de sedimentos removidos de área de lavoura pela mata ciliar, em Goiatuba (GO)

“…Estudos sobre a retenção de sedimentos em zonas ripárias em paisagens predominantemente agrícolas são de extrema importância, principalmente, na investigação da efetividade das larguras das faixas ciliares na proteção dos recursos hídricos (Phillips, 1989;Lowrance et al, 1997;Simões, 2001;Sparovek et al, 2001b;Collins et al, 2010), gerando subsídios para o estabelecimento de larguras ótimas de matas ciliares no exercício do papel-filtro na retenção de nutrientes e sedimentos advindos de áreas agrícolas.…”