Source: UNIV OF WISCONSIN submitted to
WATER QUALITY
Sponsoring Institution
State Agricultural Experiment Station
Project Status
TERMINATED
Funding Source
Reporting Frequency
Annual
Accession No.
0208459
Grant No.
(N/A)
Project No.
WIS01048
Proposal No.
(N/A)
Multistate No.
(N/A)
Program Code
(N/A)
Project Start Date
Oct 1, 2005
Project End Date
Sep 30, 2013
Grant Year
(N/A)
Project Director
Thompson, A.
Recipient Organization
UNIV OF WISCONSIN
(N/A)
MADISON,WI 53706
Performing Department
BIOLOGICAL SYSTEMS ENGINEERING
Non Technical Summary
Urban and agricultural stormwater runoff impacts surface water and ground water quality. These projects investigate 1) groundwater mounding and the potential for contaminant transport resulting from depression focused recharge beneath stormwater infiltration basins; 2) the hydraulic, physical and heavy metal removal properties of engineered soils for stormwater management; and 3) the effects of managed-intensive rotational grazing on sediment and nutrient loads from over-wintering areas.
Animal Health Component
50%
Research Effort Categories
Basic
50%
Applied
50%
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
1020210205020%
1120210205040%
1330110202040%
Goals / Objectives
GROUNDWATER MOUNDING: 1) To monitor groundwater levels and changes in soil moisture content in the unsaturated zone in response to infiltrating stormwater from an infiltration basin; 2) To apply a conservative and non-conservative tracer to the infiltration basin and monitor the migration of the tracer from the basin into the unsaturated zone and into the ground water; 3) To calibrate and validate a groundwater flow and contaminant transport model using data obtained under objectives 1 and 2; and 4) To use the model to extrapolate field data to other hydrogeologic settings. ENGINEERED SOILS: 1) To quantify infiltration, saturated hydraulic conductivity, moisture holding capacity, porosity, bulk density, and compaction susceptibility among different composite mixtures of soil, sand and compost; 2) To determine the dissolved metal removal efficiency of the composite mixtures; 3) To quantify the cation exchange capacities of the mixtures and determine the dissolved metal removal efficiency of the mixtures over time. GRAZING: 1) To quantify sediment and nutrient discharges from managed-intensive rotational grazing (MIRG) over-wintering areas due to snow melt and storm water runoff; 2) To quantify temporal changes in the sediment and nutrient discharges; 3) To determine seasonal variations in vegetation (vegetation density, leaf area index, stem density, and thatch layer) and soil (nutrients and level of compaction) characteristics and relate these characteristics to paddock management; 4) To determine the impact of vegetation and soil characteristics on runoff, sediment and nutrient discharges.
Project Methods
GROUNDWATER MOUNDING: A stormwater infiltration basin will be instrumented with a network of monitoring wells and soil moisture probes to monitor temporal variations in groundwater levels, pond levels, and moisture content in the unsaturated zone. Conservative and non-conservative tracers will be used as surrogates for potential chemicals for simulation of contaminant transport in the field. The computer software FEMWATER will be used to simulate flow and transport resulting from depression focused recharge beneath the infiltration basin. The model will be calibrated and validated using field data and used to perform sensitivity analyses on different soil properties, initial moisture content in the unsaturated zone, depth to groundwater table, depth of surface water in the pond, and changes in transport properties. ENGINEERED SOILS: Fifteen engineered soil mixtures consisting of varying amounts of sand, soil and compost will be investigated. Infiltration capacity of each mixture will be measured using flow-through column experiments. One foot of water head will be maintained above one foot of soil mixture. Moisture holding capacity, porosity, bulk density, and compaction susceptibility of each mixture will be measured before and after infiltration experiments. Saturated hydraulic conductivity will be estimated by directly measuring intrinsic (air) permeability. Metal removal efficiency will be measured using flow-through column experiments. Solutions of dissolved cadmium, copper and zinc will flow through the soil mixtures at rates approximately equal to the saturated hydraulic conductivity of each mixture. Breakthrough curves will be measured for influent with dissolved metal concentrations typical of urban stormwater. GRAZING: Surface water monitoring equipment (2-ft H-flume, ISCO automatic water sampler, and rain gauge; and culvert, area-velocity meter, and ISCO automatic water sampler) have been installed at the outlet of two over-wintering drainage areas (Columbia County and Manitowoc County). Intensive topography surveys were conducted and digital elevation models of each watershed built. Surface runoff rates will be measured and water samples collected throughout each event (snowmelt and storm runoff). Water samples will be analyzed at the UW-Stevens Point Water & Env. Anal. Lab for total suspended solids, chloride, phosphorus (total, total dissolved, and dissolved reactive phosphorus) and nitrogen (total, nitrate/nitrite, and ammonium nitrogen) species. Sediment and nutrient loads will be determined for individual events, seasons and annually. Each paddock will be sampled for vegetation density (rising plate meter and harvest method), leaf area index (LAI-2000 Plant Canopy Analyzer), stem density (manual count), and thatch layer (counting grid intercepts where thatch lies under the intercepts and soil coring to measure thatch layer thickness). Soil samples (0-5 cm) will be collected at each point and analyzed for soil N and P. A soil penetrometer will be used to measure soil compaction (top 0-10 cm). Sampling events will be conducted during spring green up, during spring lush, during summer, and during fall (prior to frost).

Progress 10/01/05 to 09/30/13

Outputs
OUTPUTS: New research was initiated in three primary areas: stormwater treatment, sediment sourcing, and reducing environmental impacts associated with land application of biosolids. Stormwater Treatment: Research was initiated at a stormwater treatment wetland in the Univeristy of Wisconsin-Madison Arboretum. Critical shear stress (an indicator of soil stability) was measured using a cohesive strength meter in wetland treatment swales and mesocosms both planted with mono- and polycultures of native plant species. Equipment for water quality (sediment, nitrogen and phosphorus) sampling was constructed and installed in order to assess removal during 2011. Sediment Sourcing: Suspended sediments play an important role in the transport of particulate P from fields to surface waters. Implementing appropriate management practices to control soil erosion and subsequent sediment delivery requires quantification of the relative contribution of sediment sources (e.g. stream bed, stream bank and upland areas under various land uses). Fingerprinting with atmospheric fallout radionuclides can be used to apportion sediment sources, and thus provide valuable guidance for management decisions. Due to their long half lives, the fallout radionuclides 137Cs and unsupported 210Pb are ideally suited for evaluating sediment transport processes that occur over long time scales. A study is being conducted in the non-glaciated region of southwestern Wisconsin in the Sugar Pecatonica River Basin, which is part of the Upper Mississippi River Basin. In-stream suspended sediment samples were collected monthly for six months using passive time integrated in-stream tube samplers. Source material samples were collected from the top 2.5 cm. Upland soil samples were collected from fields that represented various combinations of land use, soil type, and slope within the watershed. Representative samples were collected from stream beds and eroding stream banks. Approximately half of the samples collected have been analyzed for organic matter content and 137Cs and unsupported 210Pb. Radionuclide analysis was done through low background gamma counters. Data will be used to apportion in-stream suspended sediments. Biosolid Application: Research was conducted to investigate surface application of polymer coated biosolids and gypsum for reducing sediment and phosphorous transport under laboratory rainfall simulations. Experimental variables included polymer rate, polymer coating method, biosolid and gypsum prill size, and polymer type. Runoff samples were analyzed for runoff volume, total sediment, total dissolved reactive phosphorous (DRP) and total phosphorus (TP). Leachate samples were analyzed for total leachate and DRP. The P.I. mentored a post-doctoral research associate, a PhD level graduate student, two MS level graduate students, a research intern and two undergraduate students. Results were disseminated in a final report to industry, a manuscript is in preparation and six abstracts were submitted for presentation at 2011 conferences including the Wisconsin section of the AWRA, the International Meeting of ASABE, and the International Symposium on Erosion and Landscape Evolution. PARTICIPANTS: Anita Thompson, Associate Professor, Department of Biological Systems Engineering, University of WI - Madsion; John Panuska, Associate Faculty, Department of Biological Systems Engineering, University of WI - Madsion; K.G. Karthikeyan, Associate Professor, Department of Biological Systems Engineering, University of WI - Madsion; Damodhara Mailapaili, Post-doctoral Research Associate, Department of Biological Systems Engineering, University of WI-Madison. Jasmeet Lamba, Graduate Research Assistant, Department of Biological Systems Engineering, University of WI - Madsion; Zach Zopp, Research Intern, Department of Biological Systems Engineering, University of WI - Madsion; Stephanie Prellwitz, Graduate Research Assistant, Department of Biological Systems Engineering, University of WI - Madsion; Ryan Stenjem, Graduate Research Assistant, Department of Biological Systems Engineering, UW-Madison; Joy Zedler, Professor, Department of Botany, University of WI - Madison; Steve Loheide, Assistant Professor, Department of Civil and Environmental Engineering, University of WI - Madison; Graham Peaslee, Professor, Department of Chemistry, Hope College; U.S. Geological Survey; Natural Resource Conservation Service; The Nature Conservancy; Dane County Land Conservation Division; Wisconsin Department of Natural Resources; TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Changes in knowledge include the following: 1) During the first growing season in the wetland treatment swales, four primary soil and surface conditions developed and resulted in different critical shear stress values. Compared to bare soil conditions, Mnium moss, algal, and root mats within the wetland treatment swales functioned as principal soil stabilizers. Presence of the Mnium moss mat corresponded to the highest critical shear stress values (greatest soil stability), followed by algal mat, root mat, and bare soil conditions (lowest soil stability). A graduate student and research intern were trained and developed skill in using a cohesive strength meter. Changes in knowledge include the following. Polymer coated biosolid (@10 lb/acre polymer) may be an economically feasible management practice for controlling sediment transport and retaining nutrients. Applying uncoated gypsum with coated MilorganiteTM may provide additional control of solute transport. Additionally, the effectiveness of PAM-coated gypsum appears to be related to gypsum prill size. A post-doctoral research associated was trained and developed expertise in the use of a rainfall simulator and analytical equipment for phosphorus analysis. Two undergraduate students were trained in sample preparation and analysis.

Publications

  • No publications reported this period


Progress 01/01/09 to 12/31/09

Outputs
OUTPUTS: A stormwater infiltration basin (sand and gravel subsurface material) was previously instrumented with a network of monitoring wells to measure groundwater mounding in response to recharge events. Natural rainfall/runoff/infiltration events were successfully monitored during 2006 - 2008. Data from these events were analyzed and used to calibrate the groundwater flow and contaminant transport model HYDRUS-2D. The calibrated model was used to analyze critical design and subsurface hydraulic parameters that constrain infiltration basin siting to minimize mounding. The one-dimensional unsaturated HYDRUS model and the three-dimensional saturated water table flow model MODFLOW were combined to evaluate mounding and contaminant transport beneath an infiltration basin. The combined model was calibrated and tested using experimental data. MODFLOW was used to determine the effects of regional hydrogeology on the mound underneath the monitored basin. The three-dimensional saturated fate and transport code MT3D was used to simulate a tracer study and evaluate the potential for contaminant transport beneath the basin. Collaborative work was continued with the University of Alaska - Fairbanks where groundwater mounding as a result of changes in frost development due to climate warming is causing damage to homes and roads. Results were disseminated through peer-reviewed journal publications. Surface water quality monitoring stations were previously installed at the outlet of two over-wintering areas in two different MIRG farms, one in Central Wisconsin and one in Eastern Wisconsin. The over-wintering area on the Central Wisconsin farm is 28.5 acres, the soil is a Lapeer fine sandy loam, and approximately 70 dry cows and heifers graze the over-winter area from November to April. The over-wintering area on the Eastern Wisconsin farm is 16.0 acres, the soil is a Kewaunee silt loam, and approximately 435 milk cows graze the over-wintering area from November to mid-April. Spring snowmelt and runoff events were previously monitored on both farms during 2006 and 2007 and water samples were analyzed for TSS, TP, TDP, and DRP. Data were analyzed during 2009. For comparison, data were obtained from a similar study previously conducted by the Wisconsin Department of Natural Resources, the University of Wisconsin - Madison, and the U.S. Dairy Forage Research Center. An M.S. level graduate student conducted the analysis and comparison of these two data sets and began preparation of a manuscript. PARTICIPANTS: Anita Thompson: Associate Professor, Department of Biological Systems Engineering, UW-Madison; Mike Nimmer: Former graduate research assistant, Department of Biological Systems Engineering, UW-Madison, Currently Environmental Engineer, Foth, Green Bay, WI; Debasmita Misra: Associate Professor, Department of Mining and Geological Engineering, University of Alaska - Fairbanks; Roger Bannerman, Wisconsin Department of Natural Resources; Tim Radatz, Former graduate research assistant, Department of Biological Systems Engineering, UW-Madison, Currently Water Resources Engineer, Montgomery and Associaties, Cottage Grove, WI; Fred Madison, Professor, Department of Soil Science, UW-Madison; Steve Greb, Wisconsin Department of Natural Resources. TARGET AUDIENCES: Researchers, Wisconsin Department of Natural Resources, Wisconsin grazing community PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
HYDRUS-2D indicated that, for the study site (sand and gravel subsurface material), mounding was most sensitive to the thickness of the basin sedimentation layer and the hydraulic conductivity; mound height increased as both the sediment layer and the hydraulic conductivity decreased. Ideal basin siting conditions to minimize mounding were found to occur in a material with high saturated hydraulic conductivity and with thick unsaturated and saturated layers. These results were described in a peer-reviewed journal publication. The previously calibrated HYDRUS-2D was used to predict water table mounding under hypothetical design scenarios. For sandy loam and loamy sand subsurface materials, water table mounding is affected by both basin design features and by aquifer properties. Mound heights increase as the thickness of both the unsaturated and saturated zones decrease. Mound heights increase as the initial soil moisture, basin size and ponding depth increase. A thin sedimentation layer on the basin floor delays mound formation, but only slightly decreases the maximum mound height. These results were described in a peer-reviewed journal publication and could be used to inform future selection of infiltration basin locations, particularly in a glacial till environment in Wisconsin. Potential environmental impacts from over-wintering depend on animal density, amount of time in over-wintering areas, and texture of soils.

Publications

  • Thompson, A.M. M. Nimmer and D. Misra. 2009. Effects of variations in hydrogeological parameters on water-table mounding in sandy loam and loamy sand soils beneath stormwater infiltration basins. Hydrogeology Journal. doi 10.1007/s10040-009-0532-1.
  • Nimmer, M., A.M. Thompson, and D. Misra. 2009. Water table mounding beneath stormwater infiltration basins. Journal of Environmental and Engineering Geoscience. 15:67-79.


Progress 01/01/08 to 12/31/08

Outputs
OUTPUTS: A stormwater infiltration basin (sand and gravel subsurface material) was previously instrumented with a network of monitoring wells to measure groundwater mounding in response to recharge events. Natural rainfall/runoff/infiltration events were successfully monitored during 2006 and 2007. Data from these events were analyzed and used to calibrate the groundwater flow and contaminant transport model HYDRUS-2D. The calibrated model was used to analyze critical design and subsurface hydraulic parameters that constrain infiltration basin siting to minimize mounding. The one-dimensional unsaturated HYDRUS model and the three-dimensional saturated water table flow model MODFLOW were combined to evaluate mounding and contaminant transport beneath an infiltration basin. The combined model was calibrated and tested using experimental data. MODFLOW was used to determine the effects of regional hydrogeology on the mound underneath the monitored basin. The three-dimensional saturated fate and transport code MT3D was used to simulate a tracer study and evaluate the potential for contaminant transport beneath the basin. Additional field data was collected during 2008. A M.S. level graduate student was mentored on this project. Collaborative work was initiated with the University of Alaska where groundwater mounding as a result of changes in frost development due to climate warming is causing damage to homes and roads. Surface water quality monitoring stations have been installed at the outlet of two over-wintering areas in two different Management Intensive Rotational Grazing farms, one in Central Wisconsin and one in Eastern Wisconsin. The over-wintering area on the Central Wisconsin farm is 28.5 acres, the soil is a Lapeer fine sandy loam, and approximately 70 dry cows and heifers graze the over-winter area from November to April. The over-wintering area on the Eastern Wisconsin farm is 16.0 acres, the soil is a Kewaunee silt loam, and approximately 435 milk cows graze the over-wintering area from November to mid-April. Spring snowmelt and runoff events were previously monitored on both farms during 2006 and 2007 and water samples were analyzed for TSS, TP, TDP, and DRP. Data were analyzed and results are currently being summarized. For comparison, data were obtained from a similar study previously conducted by the Wisconsin Department of Natural Resources, the University of Wisconsin - Madison, and the U.S. Dairy Forage Research Center. Two M.S. level graduate students were mentored as part of this project. Findings were presented at the 2008 USDA-CSREES National Water Conference. PARTICIPANTS: Individuals: Anita Thompson, Principal Investigator, UW Biological Systems Engineering; Fred Madison, Co-Principal Investigator, UW Soil Science; Amanda Crowe, Graduate Student, UW Biological Systems Engineering; Tim Radatz, Graduate Student, UW Biological Systems Engineering; Collaborators: Steve Greb, Wisconsin Department of Natural Resources TARGET AUDIENCES: Researchers, Wisconsin grazing community PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
HYDRUS-2D indicated that, for the study site (sand and gravel subsurface material), mounding was most sensitive to the thickness of the basin sedimentation layer and the hydraulic conductivity; mound height increased as both the sediment layer and the hydraulic conductivity decreased. For sandy loam and loamy sand subsurface materials, water table mounding is affected by both basin design features and by aquifer properties. Mound heights decrease as unsaturated thickness increases, with greater changes in mound height occurring at smaller unsaturated thicknesses. Mound heights decrease as the saturated thickness increases, but to a lesser degree compared to unsaturated thickness. Mound heights decrease as the initial water content decreases. Mound heights decrease as anisotropy increases with more notable effects for horizontal to vertical hydraulic conductivity ratios of 10:1 and below. Mound heights increase as both basin size and ponding depth increase. Due to the similarity in texture to the aquifer material, a thin sediment layer does not affect mound heights. The HYDRUS / MODFLOW model combination produced modeled heads at the center of the basin that were in close agreement with measured values for all monitored runoff ponding events, and calibrated hydraulic conductivities were within an order of magnitude of measured values. Although the unsaturated zone was thin and comprised of coarse material, an attenuation of recharge by approximately two hours justified the need to couple an unsaturated model (HYDRUS) with MODFLOW. Regional hydrogeology adjacent to the basin affected mounding by causing a prolonged mound recession underneath the basin. Mounding caused more rapid spreading of contamination added to the basin. Mounding decreased the arrival time of peak contaminant concentration by approximately 13 and 9 hours at 10 and 20 meters, respectively, downgradient of the basin center, and by approximately 40 hours at 20 meters sidegradient of the basin. Addition of a conservative tracer (1,000 mg/L over a one hour period) resulted in contaminant concentrations below 2.0 mg/L downgradient and sidegradient of the injection point in all simulations. Maximum concentrations were between 30 - 40 percent lower with mounding than without mounding at both the 10 and 20 m downgradient locations. At the 20 m sidegradient location, concentrations with mounding were approximately one order of magnitude higher than without mounding. In summary, the HYDRUS / MODFLOW model combination was capable of predicting mound formation reasonably well as observed at the infiltration basin. The MT3D model simulation of tracer transport showed mound formation to cause more rapid tracer movement away from the basin compared to the natural gradient.

Publications

  • Thompson, A.M., A.C. Paul, and N.J. Balster. 2008. Physical and hydraulic properties of engineered soil media for bioretention basins. Transactions of the American Society of Agricultural and Biological Engineers. 51(2):499-514.
  • Nimmer, M., A.M. Thompson, and D. Misra. 2008. Water table mounding beneath stormwater infiltration basins. Journal of Environmental and Engineering Geoscience. (Accepted for publication)
  • Thompson, A.M. and M. Nimmer. 2008. Variational analysis of water table mounding model for stormwater infiltration basin siting. Hydrogeology Journal. (In Review)
  • Nimmer, M., A.M. Thompson, and D. Misra. 2008. Modeling water table mounding and contaminant transport beneath stormwater infiltration basins. Journal of Hydrologic Engineering. (In Review)


Progress 01/01/07 to 12/31/07

Outputs
OUTPUTS: A stormwater infiltration basin (sand and gravel subsurface material) was instrumented with a network of monitoring wells to measure groundwater mounding in response to recharge events. Natural rainfall/runoff/infiltration events were successfully monitored during 2006 and 2007. Data from these events were analyzed and used to calibrate the groundwater flow and contaminant transport model HYDRUS-2D. The calibrated model was used to evaluate hypothetical basin operation scenarios with parameters obtained from the Wisconsin Department of Natural Resources post-construction stormwater standards 1002 and 1003. The three dimensional saturated flow code MODFLOW was used to determine the effects of regional hydrogeology on the mound underneath the basin. A M.S. level graduate student was mentored on this project. Results were presented at the 2007 Annual International Meeting of the American Society of Agricultural and Biological Engineers and the 2007 Fall Meeting of the American Geophysical Union. Fifteen engineered soil mixtures consisting of varying amounts of sand, soil and compost were investigated. Infiltration capacity of each mixture was measured using flow-through column experiments. Moisture holding capacity, porosity, bulk density, and compaction susceptibility of each mixture were measured before and after infiltration experiments. Saturated hydraulic conductivity was estimated by directly measuring intrinsic (air) permeability. Solutions of dissolve cadmium, copper and zinc flowed through the soil mixtures at rates approximately equal to the saturated hydraulic conductivity of each mixture and removal rates determined. Data from these experiments were analyzed. A M.S. level graduate student and a Post-doctoral Research Associate were mentored as part of this project. Surface water quality monitoring stations have been installed at the outlet of two over-wintering areas in two different MIRG farms, one in Central Wisconsin and one in Eastern Wisconsin. The over-wintering area on the Central Wisconsin farm is 28.5 acres, the soil is a Lapeer fine sandy loam, and approximately 70 dry cows and heifers graze the over-winter area from November to April. The over-wintering area on the Eastern Wisconsin farm is 16.0 acres, the soil is a Kewaunee silt loam, and approximately 435 milk cows graze the over-wintering area from November to mid-April. Spring snowmelt and runoff events were successfully monitored on both farms during 2007 and water samples were analyzed for TSS, TP, TDP, and DRP. Data from 2007 were combined with data collected during 2006 and are currently being analyzed. A M.S. level graduate student was mentored as part of this project. PARTICIPANTS: Anita Thompson, P.I.; Mike Nimmer, Graduate Research Assistant; Wisconsin Department of Natural Resources; Brian Lepore, Research Associate; Adam Paul, Graduate Research Assistant; Amanda Crowe, Graduate Research Assistant; TARGET AUDIENCES: Regulators; Engineers; Scientific Community

Impacts
HYDRUS-2D indicated that, for the study site, mounding was most sensitive to the thickness of the basin sedimentation layer and the hydraulic conductivity; mound height increased as both the sediment layer and the hydraulic conductivity decreased. For hypothetical basins with less permeable subsurface material, the mound height was most sensitive to hydraulic conductivity and unsaturated zone thickness. Mound heights increased as both basin size and ponding depth increased. Mound heights increased more rapidly with ponding depth as the basin size increased, suggesting that a larger number of smaller-sized infiltration basins would be preferable to one large basin. MODFLOW results suggested that recharge from upgradient of the infiltration basin contributed to the prolonged mound recession observed underneath the basin. Steady-state infiltration rates were high for all engineered soil mixtures and were greatest for mixtures containing sand and compost only followed by mixtures containing sand, compost, and sandy soil followed by mixtures containing sand, compost, and silt loam soil. Infiltration rates for mixtures containing sand and compost only and mixtures containing sand, compost, and sandy soil exhibited a significant linear relationship with the ratio of sand to compost. Bulk density of the mixtures was inversely related to the proportion of compost and was greatest for mixtures containing sand, compost, and silt loam soil followed by mixtures containing sand, compost, and sandy soil followed by mixtures containing sand and compost only. Conversely, moisture holding capacity increased with the proportion of compost. Bulk density, moisture holding capacity, and compaction were all linearly related to the ratio of sand/compost in the mixture. Although, at least initially, compost controlled the physical density of these mixtures, the textural class of the mineral component represented a more dominant control over the movement of water into and through these mixtures. Thus, a soil component appears to interact with the compost-amended bioretention media to stabilize infiltration and dampen the effect of changing the ratio of sand/compost in the mixture on bulk density, moisture holding capacity, and compaction relative to mixtures of solely sand and compost. For influent concentrations typical of urban stormwater, removal efficiency ranged from 98.2 to 99.8 percent for Zn, 97.3 to 98.2 percent for Cd and 94.1 to 96.7 percent for Cu. The mixtures' compost component released dissolved organic matter which caused a temporary reduction in removal efficiency at the beginning of the flow-through experiments. Additional flow-through experiments were conducted on five of the fifteen mixtures with elevated influent concentrations of all three metals. For the four mixtures containing top soil, the delay of breakthrough corresponded to the mass weighted cation exchange capacity. With the exception of the mixture with the lowest mass weighted cation exchange capacity, the onset of breakthrough occurred between 45 and 65 pore volumes.

Publications

  • Paul, A.C., A.M. Thompson, and N. Balster. 2008. Physical and Hydraulic Properties of Engineered Soil Media for Bioretention Basins. Trans. ASABE. Accepted for Publication.
  • Lepore, B.J., A.M. Thompson, and A. Paul. 2008. Heavy Metal Removal Efficiency of Engineered Soil for Bioretention. Chemosphere. In Review.
  • Nimmer, M. 2007. Groundwater Mounding Beneath Stormwater Infiltration Basins. M.S. Thesis. University of Wisconsin-Madison.


Progress 01/01/06 to 12/31/06

Outputs
A stormwater infiltration basin was instrumented with a network of monitoring wells, soil moisture probes, suction cup samplers, and thermocouples to monitor temporal variations in groundwater levels, pond levels, moisture content in the unsaturated zone, and soil temperature, and to collect water samples from the unsaturated and saturated zones. Natural rainfall/runoff events were successfully monitored during 2006. Data from these events is being used to calibrate and validate the groundwater flow and contaminant transport model HYDRUS-2D. A preliminary model design has been completed with basin geometry, soil types, aquifer properties, and boundary and initial conditions appropriate to the site. Fifteen engineered soil mixtures consisting of varying amounts of sand, soil and compost were investigated. Infiltration capacity of each mixture was measured using flow-through column experiments. Moisture holding capacity, porosity, bulk density, and compaction susceptibility of each mixture were measured before and after infiltration experiments. Saturated hydraulic conductivity was estimated by directly measuring intrinsic (air) permeability. Solutions of dissolve cadmium, copper and zinc flowed through the soil mixtures at rates approximately equal to the saturated hydraulic conductivity of each mixture and removal rates determined. Surface water quality monitoring stations have been installed at the outlet of two over-wintering areas in two different MIRG farms, one in Central Wisconsin and one in Eastern Wisconsin. The over-wintering area on the Central Wisconsin farm is 28.5 acres, the soil is a Lapeer fine sandy loam, and approximately 70 dry cows and heifers graze the over-winter area from November to April. The over-wintering area on the Eastern Wisconsin farm is 16.0 acres, the soil is a Kewaunee silt loam, and approximately 435 milk cows graze the over-wintering area from November to mid-April. Spring snowmelt and runoff events were successfully monitored on both farms during 2006 and water samples were analyzed for TSS, TP, TDP, and DRP. From March - August 2006, the fraction of precipitation that became runoff was less than 1% from the Central Wisconsin over-wintering area compared to 19% from the Eastern Wisconsin over-wintering area, indicating the role of soil texture in runoff production. Significantly greater sediment and phosphorus loss occurred from the over-wintering area on the Eastern Wisconsin farm compared to the over-wintering area on the Central Wisconsin farm. These differences in runoff and sediment and phosphorus losses result from differences in soil texture and herd density within the over-wintering areas. In the majority of events, TDP was the main form of P in runoff from both over-wintering areas. However, periods of rain on frozen ground and/or low vegetative cover resulted in high sediment and particulate P losses in runoff. At four times during 2006, each paddock was sampled for vegetation density, leaf area index, and stem density. Soil samples (0-5 cm) were collected at each point and analyzed for soil N and P. A soil penetrometer was used to measure soil compaction (top 0-10 cm).

Impacts
This research: 1) furthers our understanding of the impact of urban and agricultural runoff on surface and groundwater quality and 2) evaluates and improves the design of management practices to mitigate those impacts.

Publications

  • No publications reported this period