HR: 0800h
AN: H21E-1399    [Abstracts]
TI: Use of Polyacrylamide to Reduce Seepage From Unlined Irrigation Canals: Initial Results From Small Scale Test Troughs
AU: * Susfalk, R B
EM: rbs@dri.edu
AF: Desert Research Institute, 2215 Raggio Parkway, Reno, NV 89512 United States
AU: Young, M H
EM: michael.young@dri.edu
AF: Desert Research Institute, 755 East Flamingo Road, Las Vegas, NV 89119 United States
AU: Schmidt, M
EM: h2osoco@aol.com
AF: US Bureau of Reclamation, 2764 Compass Road, Grand Junction, CO 81506 United States
AU: Epstein, B J
EM: brian@hydsol.com
AF: Hydrologic Solutions, LLC, 190 East 7th Avenue, Durango, CO 81301 United States
AU: Goreham, J
EM: jgoreham@dri.edu
AF: Desert Research Institute, 755 East Flamingo Road, Las Vegas, NV 89119 United States
AU: Swhihart, J
EM: JSWIHART@do.usbr.gov
AF: US Bureau of Reclamation, Denver Fed Center, Bldg 67, POB 25007, Denver, CO 80225 United States
AU: Smith, D
EM: dmsmith@do.usbr.gov
AF: US Bureau of Reclamation, Denver Fed Center, Bldg 67, POB 25007, Denver, CO 80225 United States
AB: Polyacrylamide (PAM) is a class of long-chain synthetic polymers that are used extensively in food packaging, paper manufacturing, wastewater treatment, and as a soil amendment to reduce erosion. Recent empirical evidence has shown that applying linear, anionic PAM seepage can also reduce seepage from unlined irrigation canals. A diverse set of experiments has been initiated to understand the efficacy of PAM usage in ditch environments. The experiments span multiple scales, from small-scale bench top and artificial furrow experiments, to larger engineered furrows and irrigation ditches. Our objective was to assess the effectiveness of different PAM application methods and concentrations on seepage reductions in small scale, artificial Test Troughs (TT). The TT consists of two 24 m long, 10 cm deep furrows formed from native ASTM C-33 sand. During water application, inflows, outflows, and seepage from under the furrows were continuously measured. PAM in either granular or partially hydrated form was applied at various rates. The results presented here cover one facet of the research program. The application of granular PAM to the TT reduced seepage from 49 L/min to less than 22 L/min, depending on treatment. A PAM application rate of 44 kg/(canal ha) reduced seepage by 69+/-9 percent, and was more effective than an application rate of 11 kg/(canal ha) that reduced seepage by 56+/-22 percent. Seepage reduction was calculated using flow rates between 400 and 600 elapsed minutes. Inclusion of later data (up to 1440 min) into seepage calculations was complicated by a reduction in seepage at the control trough caused either by a reduction in head or deposition of suspended sediment. We hypothesize that the PAM-sediment layer present in the treated trough exerted a greater control on seepage than sediment deposition alone. However, heavy suspended sediment loads associated with hydrologic events reduced seepage rates within both the control and treated troughs, somewhat masking the effects of the PAM. The application of linear, anionic PAM to the artificial Test Troughs did significantly reduce seepage rates. Additional work will be necessary to scale these results up to larger ditches, and to assess if the seepage reduction occurring by suspended sediment deposition is an artifact of this small scale experiment.
DE: 1838 Infiltration
DE: 1865 Soils (0486)
DE: 1880 Water management (6334)
DE: 1899 General or miscellaneous
SC: Hydrology [H]
MN: Fall Meeting 2005