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WATER RESOURCES RESEARCH GRANT PROPOSAL

Project ID: 2002MO3B

Title: Soil Erosion and Runoff Reduction Using Three Methods of Polyacrylamide Application

Project Type: Research

Focus Categories: Climatological Processes, Conservation, Methods

Keywords: Soil Erosion, Runoff Reduction, Polyacrylamide, methods

Start Date: 03/01/2003

End Date: 02/29/2004

Federal Funds: $21060.00

Matching Funds: $43535.00

Congressional District: Missouri 8th

Principal Investigators: Gantzer, Clark; Anderson, Stephen H

Abstract: Urban expansion in the U.S. annually covers an area of ~12,950 km2. Increased runoff and erosion during construction causes significant nonpoint source water pollutants. The use of anionic Polyacrylamide (PAM) shows promise as a way to reduce runoff and erosion when used with other erosion measures. Laboratory tests at the University of Missouri have shown that surface applied PAM can reduce soil erosion by ~50 % at application rates of 4.5 kg ha1 (Thompson et al., 2001). This study will evaluate the duration of any erosion and runoff reduction as a result of using different application methods of PAM to soil protect soil. The research objective is to determine the amount of rainfall that PAM-treated soil can withstand before erosion returns to an untreated rate of detachment and runoff. The goal of this work is to develop guidelines for use of PAM to reduce soil erosion on bare soil associated with construction sites until protective vegetative cover is established. A laboratory study will be conducted using a rainfall simulator on bare-surfaced soil beds of 1 by 0.3 by 0.3m on a 5% slope of a Mexico silt loam soil (fine, smectitic, mesic Aeric Vertic Epiaqualf). Mexico soils are sensitive to surface sealing and are highly erodible. Disturbed soils will be collected and air-dried. Soils will be sieved to pass a 4-mm sieve and packed into soil beds to a bulk density of ~1.3 g cm3. Rainfall will be applied at a rate of 50 mm hr-1. The energy of rainfall will be adjusted to a value of 1.28 kJ m-2. Treatments will include: (1) Bare Soil (Control), (2) Dry granular PAM at 9 kg ha -1 + 5,000 kg ha -1 gypsum surface-applied to a moist soil, (3) Solution PAM at 9 kg ha -1 + 5,000 kg ha -1 gypsum surface-applied to a moist soil, and (4) Dry granular PAM at 9 kg ha -1 + 5,000 kg ha -1 gypsum mixed in top 10mm of a dry soil and then wet. Rainfall and runoff rates will be monitored throughout the experiment. Soil strength of surface seals will be studied using a fall-cone device (Hansbo, 1957; Towner, 1973). “Ultra high resolution” x-ray computed tomography (CT) of “intact” soil surface seals formed from raindrop impact will be used to create 3D volume rendered images to measure the surface seal macropore volume, number, size-distribution, perimeter, circularity, topological dimension, pore-connectivity, tortuosity, volume and width on a 0.01- by 0.01- by 0.01-mm scale before and after rainfall. This will allow direct evaluation of soil stabilization as a result of surface applications of PAM.

Progress/Completion Report PDF


U.S. Department of the Interior, U.S. Geological Survey
URL: http://water.usgs.gov/wrri/02-03grants_new/2002MO3B.html
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Last Updated: Thursday June 24, 2004 3:18 PM
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