Goodwater Creek, Missouri
An ARS
Benchmark Research Watershed
Characteristics
Goodwater
Creek Experimental Watershed (GCEW) is in the SW headwaters of the Salt River
Basin in northeastern Missouri, which is the source of water to the Mark Twain
Lake, a 75 km2 Army Corp of Engineers reservoir that is the major
public water supplier in the region. The Salt River system encompasses an area
of 6450 km2 within portions of 12
northeastern Missouri counties, including the 72 km2GCEW. Soils
within GCEW were formed in Wisconsin and Illinoian
loess overlying pre-Illinoian glacial till.
Illuviation of the high clay content loess resulted in the formation of argillic horizons containing 40-60% smectitic
clays. Topography within the watershed is flat to gently rolling, with most
areas having 0-3% slopes. The Adco-Putnam-Mexico soil
association predominates in the flatter upland areas, and these soils tend to
be less eroded and have greater depths to the claypan than the terrace areas.
The Mexico-Leonard soil associations occur in more sloping terrace and alluvial
areas where the depth to claypan is often <15 cm on side slopes because of
erosion. The claypan is not present in alluvial areas immediately adjacent to
streams. The naturally formed claypan represents the key hydrologic feature of GCEW,
and it is the direct cause of the high runoff potential of these soils. Most
soils within GCEW are classified as Hydrologic Group C or D by NRCS. Land use
is predominately agricultural. The primary row crops are soybeans, corn, and
sorghum. Forage production is mainly tall fescue. Livestock production is
mainly beef cattle. Average annual precipitation is about 1000 mm per year, and
stream flow (based on GCEW data) accounts for about 30% of precipitation.
Runoff accounts for about 85% of total stream flow. Despite high runoff
potential and poorly drained soils, sub-surface drainage is not employed
because of the difficulties of installation in or below the claypan.
Environmental Impacts
The primary water quality concern is runoff contaminated with sediments, nutrients (P, NO3-,
NH4+), pesticides, and water-borne pathogens.
The
naturally formed claypan soils that predominate
within the basin create a barrier to percolation and promote surface runoff.
This results in a high degree of vulnerability to surface transport of
sediment, herbicides, and nutrients. The GCEW has a known and well-documented
history of herbicide and sediment contamination problems. Being a headwater
watershed of the Salt River Basin, contaminant transport in GCEW reflects the
environmental issues in Mark Twain Lake. Mark Twain Lake serves a public
drinking water supply for approximately 42,000 people, and consistently high
spring and summer time atrazine levels have been an on-going concern. More
recently, late summer algal blooms have created the need for more extensive
water treatment to reduce odor and taste problems in drinking water, and may be
a reflection of increased nutrient transport within the basin.
Management Practices
Studies
are currently underway at field and plot scales to study the water quality
impact of a broad range of cropping systems that incorporate various conservation
practices. These studies include a precision agriculture system on an 88-acre
field (Conservation practice #’s 590, 329A), plot-scale studies of the effectiveness
of grass filters and grass hedges on contaminant mitigation from edge-of field
runoff (393), alternative weed management systems focused on reducing herbicide
inputs (595), measuring soil quality under different grain and bioenergy cropping
systems, and the potential for enhanced herbicide degradation in contour grass
buffer strips (332). In addition, hydrologic simulation models are being used
to predict water quality at multiple scales, determine contaminant source areas
within watersheds, and serve as decision support aids for BMP implementation.
Research Objectives
Prevailing and traditional agronomic practices
for row crop production have degraded soil and water resources in the
Midwestern claypan soils region. Soil and water
quality are inextricably connected, and surface runoff is the key hydrologic
process that physically links them. Individual research projects are integrated
by the development, implementation, and assessment of cropping systems and Best
Management Practices (BMPs) to improve soil and water quality. An additional
level of impact stems from the development of watershed models as tools for BMP
assessment and watershed planning.
Specific objectives are to: 1) develop systems
incorporating biological assays and electronic sensor technology to better
understand soil quality impacts of different management systems; 2) conduct field- and watershed-scale
studies to assess the contribution of surface runoff, interflow, and
groundwater recharge to contaminant transport in claypan
watersheds; 3) develop criteria, evaluate performance, and determine impacts of
alternative cropping systems and BMPs that reduce herbicide, nutrient, and
sediment contamination, sustain productivity, and improve resilience to climate
variability; 4) validate and improve watershed models to better assess the
impact of field-scale management practices and watershed-scale management
policies on surface water quality; and 5) Improve watershed management and
ecosystem services through long-term observation, characterization, delivery,
and application of information from agricultural watersheds and landscapes..
Approaches
The implementation of Best Management
Practices (BMPs) to improve soil and water quality must be balanced with the
need for socially acceptable practices that sustain profitable crop production.
Our vision to meet this challenge entails an array of conservation, agronomic,
and soil management practices. The proposed research encompasses three main
approaches: (1) studies addressing the parameters and practices that control
soil and water quality; (2) studies designed to test the effectiveness and
economic impact of various BMPs and alternative cropping systems; (3)
application of computer models to simulate the impact of BMPs on surface water
quality at field and watershed scales. These broad objectives are divided into
multiple individual projects tied together by a common goal: the effective
implementation of BMPs to improve and sustain soil and water resources.
Projects include studies ranging from assessment of soil and water quality to
application of genetic-based techniques for detection of water-borne pathogens
to development and testing of new agronomic and conservation management
practices. Expected results include improved indexing of soil quality
parameters, new and profitable BMPs for field crop production that protect or
improve soil and water quality, and a validated model for improved surface
water quality assessment and planning. Specific benefits include:
1) productive agricultural systems that are proven to provide soil and water
quality benefits; 2) cost-effective implementation of vegetative buffer
strips to reduce contaminant transport in surface runoff; 3)
increased confidence in models to simulate vegetative buffer strips; 4)
increased confidence in simulation tools for assessing impacts of climate
change; and 5) ability to better target and manage conservation programs. Our long-term water quality monitoring
will allow for an objective determination of the changes in water quality and
provide feedback on the need for greater adoption of practices within
sub-watersheds of Long Branch Creek. In addition, the long-term hydrologic and
weather data collected over the last 40 years within Goodwater Creek
Experimental Watershed will aid our understanding of how climate change is
impacting precipitation patterns, stream discharge, and ultimately
watershed-scale runoff response and associated contaminant transport.
Measurements In Place and Planned Water quality is
monitored at the GCEW outlet, at a 35-ha farm field, and on 18 0.34-ha plots
within GCEW. The field and watershed monitoring stations are equipped with
v-notch weirs, flowmeters, and automatic samplers;
the plots have Parshall flumes with similar flowmeters, and automatic samplers. At the plot and field
scale, samples are collected for all runoff events. Shallow groundwater is also
collected at five locations within the field each year and analyzed for
dissolved nitrate levels. At the watershed scale, grab samples are collected
weekly, and all runoff events are sampled by the automatic sampler. At all
surface-monitoring sites, contaminant monitoring includes commonly used corn
and soybean herbicides, dissolved and total N and P, and sediment.
Collaborators and Cooperating agencies
and groups
There are numerous
agencies and groups currently involved in some type of CEAP-related activities
within the Mark Twain/Salt River Basin as a whole.
Federal partners: NRCS, USGS, and EPA.
State partners: MO Departments of
Natural Resources, Conservation, and Agriculture; University of Missouri Water
Quality Extension (including the MO Watershed Information Network).
Local/regional partners: CCWWC, Soil
and Water Conservation Districts, Mark Twain Water Quality Initiative.
Non-profit advocacy partners: MO Corn
Growers Association, Environmental Resources Coalition.
Selected recent publications