Lupinus perennis production field

Stormwater Part 2: Ag Run-off and Restoration

Apr 13, 2015

Beautiful and sunny here at the Nursery as storms and a cold front rolled through last night. During the previous days our staff took advantage of some favorable winds to finish up the prescribed burning here on the grounds, which included burning plots of Sporobolus heterolepis (prairie dropseed), Koeleria pyramidata (June grass), and Spartina pectinata (prairie cord grass).

Burning grass plots at Cardno Nursery

Our last post began a discussion about stormwater (mis)management, both in rural and urban areas, and some of the consequences associated with those management strategies. Indeed, along with sunlight, clean water is our most valuable natural resource, and is becoming increasingly scarce, as we’re seeing in places like California. We talked in the last post about the ways in which contemporary water management systems rely on a strategy to “collect, convey, and discharge” water away from urban areas and farm fields as quickly as possible. This inevitably results in cycles of flooding, drought, and degradation of riparian and other aquatic ecosystems.

However, in addition to water quantity and flows, modern water management strategies also negatively affect the water quality of our rivers, streams, lakes, groundwater, and even oceans. Many of you will, by now, be aware of the catastrophic dead zones—also known as hypoxic zones-- present at the mouths of our large river systems, most notably where the Mississippi River empties in the Gulf of Mexico.

Dead Zone Map

There are several contributors to water quality degradation in our lakes, rivers, and groundwater here in the Midwest, but the two greatest factors currently are agricultural runoff from farm fields and sewage inputs from combined sewer overflow (CSO) systems in urban areas.  Significant parameters affected by this runoff include temperature, nutrient loads, turbidity, and heavy metals. We’ll look at agricultural runoff and CSOs in turn, as well as some green solutions (which necessarily incorporate native plants, of course) that can help improve our water quality.

Problem: Agricultural Runoff

Nitrogen and phosphorus are at the root of the dead zone problem. Agricultural inputs, including fertilizers, herbicides, and pesticides are able to quickly pass into the groundwater and watershed through percolation and tile drainage systems. Fertilizer use has been steadily increasing over the past 50 years, both in the United States and around the world.  Heavier nutrient loads are responsible for the aforementioned dead zones, dangerous algal blooms, Blue Baby Syndrome, and general water eutrophication, which can have dramatic effects on aquatic ecosystems.

DRAIN TILE PHOTO

Programs, such as the USDA’s Conservation Reserve Program (CRP), encourage farmers and rural landowners to set aside portions of their land as natural areas, in return for rental payments. These natural areas, especially when buffering fields from waterways, help to sequester many of the nutrients coming off of ag fields. Unfortunately, between 2007 and 2013, the total enrollment in the CRP program dropped by nearly 10 million acres, a 25% percent reduction.

Solution: Nutrient Farming and Wetland Restoration

Short of a large-scale revolution in current agricultural practices, several potential opportunities exist to remediate agricultural runoff before it reaches our watersheds. One is known as “nutrient farming,” and is being propounded by organizations such as the Wetlands Initiative in Chicago, IL. Nutrient farming proponents hope to develop nutrient markets that encourage landowners to restore wetlands and buffer zones on their properties. The incentive to do so would come in the form of credits generated from these restorations, which could be sold to municipalities, industrial facilities, or other sources of significant nutrient pollution.

WETLAND PHOTO

Pilot markets are already being tested—such as the Ohio River Basin Trading Project, and in the Chesapeake Bay watershed.

The Wetlands Institute indicates that large-scale wetland restorations, when placed at strategic points in a watershed, can filter and sequester a significant portion of nutrients and other pollutants entering the watershed.

Cardno Native Plant Nursery has often provided native plants and seeds for the Wetland Initiatives’ restoration projects, as well as countless other wetland restoration projects around the Midwest.  

In our next post, we’ll look at Combined Sewer Overflow systems, and the ways in which green infrastructure, incorporating native plants, can play a big role toward improving water quality.

Common Arrowhead (Sagittaria latifolia)