Managing Artificially Drained Low-Gradient Agricultural Headwaters for Enhanced Ecosystem Functions

Abstract

Large tracts of lowlands have been drained to expand extensive agriculture into areas that were historically categorized as wasteland. This expansion in agriculture necessarily coincided with changes in ecosystem structure, biodiversity, and nutrient cycling. These changes have impacted not only the landscapes in which they occurred, but also larger water bodies receiving runoff from drained land. New approaches must append current efforts toward land conservation and restoration, as the continuing impacts to receiving waters is an issue of major environmental concern. One of these approaches is agricultural drainage management. This article reviews how this approach differs from traditional conservation efforts, the specific practices of drainage management and the current state of knowledge on the ecology of drainage ditches. A bottom-up approach is utilized, examining the effects of stochastic hydrology and anthropogenic disturbance on primary production and diversity of primary producers, with special regard given to how management can affect establishment of macrophytes and how macrophytes in agricultural landscapes alter their environment in ways that can serve to mitigate non-point source pollution and promote biodiversity in receiving waters.

Exploring water cycle dynamics by sampling multiple stable water isotope pools in a developed landscape in Germany

“…1a). The Schwingbach and its main tributary the Vollnkirchener Bach are low mountainous creeks and have an altitudinal difference of 50-100 m over a 5 km distance (Perry and Taylor, 2009) (Fig. 1c) with an altered physical structure of the stream system (channelled stream reaches, pipes, drainage systems, fishponds).…”

“…Through changes in land use, land cover, irrigation, and draining, agriculture has substantially modified the water cycle in terms of both quality and quantity (Gordon et al, 2010) as well as hydrological functioning (Pierce et al, 2012). Hrachowitz et al (2016) recently stated the need for a stronger linkage between catchment-scale hydrological and water quality communities.…”

Little River Drainage District conversion of Big Swamp to fertile agricultural land

“…Further, the straightening of streams and channelization of water to move water off fields is a source of soil erosion and bank scouring that needs constant attention to control sedimentation throughout the system. One of the big challenges that Mississippi River drainage districts and the USACE face is how to best manage the water velocity and emergent vegetation in their drainage systems to control seasonal flooding, keep the channel beds stable, and reduce off-field and landscape-wide nutrient losses while creating habitat diversity under seasonal drought and uncertain climate patterns (Pierce et al 2012 …”

“…Southeast Missouri, once one of the world's largest tracts of forested bottomlands, was a vast wilderness of bald cypress (Taxodium distichum L.), tupelo (gum; Nyssa L.), hardwoods, and water (figure 1), barely accessible to settlers migrating west. In the early 1890s, these historic river floodplains and their tributaries were drained and transformed into fertile agricultural lands in an ambitious engineering feat comparable to the construction of the Panama Canal (Pracht and Banks 2002;Pierce et al 2012).…”

“…Today this vast network of ditches (figure 2), channels, and levees in southeast Missouri bottomlands makes possible an intensive system of agriculture, which produces almost a third of Missouri's agricultural economic output and has changed the hydrology, nutrient cycling, biodiversity, and structure of the entire ecosystem (Pierce et al 2012). Unified and managed by the Little River Drainage District (LRDD; figure 3) with support from the US Army Corps of Engineers (USACE) (Camillo 2012), this region drains 208,000 ha (520,000 ac) of bottomlands and is the drainage outlet for the runoff from 480,000 ha (1.2 million ac) of bottomlands and uplands to the Mississippi River at Helena,…”