Controlling Tailwater Sediment and Phosphorus Concentrations with Polyacrylamide in the Imperial Valley, California

Abstract

External loading of phosphorus (P) from agricultural surface discharge (tailwater) is the main cause of excessive algae growth and the eutrophication of the Salton Sea, California. Continuous polyacrylamide (PAM) applications to agricultural irrigation water inflows were evaluated as a means of reducing sediment and P in tailwater. Zero (control) and 1 mg L(-1) PAM (PAM1) treatments were compared at 17 Imperial Valley field sites. Five and 10 mg L(-1) PAM treatments (PAM5, PAM10) were conducted at one site. The particulate phosphorus (Pp) fraction was determined as the difference between total phosphorus (Pt) and the soluble phosphorus (Ps) fraction. We observed 73, 82, and 98% turbidity reduction with PAM1, PAM5, and PAM10 treatments. Although eight field sites had control tailwater sediment concentrations above the New River total maximum daily loads (TMDL), all but one were made compliant during their paired PAM1 treatments. While PAM1 and PAM10 reduced tail water Pp by 31 and 78%, none of the treatments tested reduced Ps. This may have been caused by high irrigation water Na concentrations which would reduce Ca adsorption and Ca-phosphate bridging on the PAM. The PAM1 treatments resulted in <0.5 mg L(-1) drain water polyacrylamide concentrations 1.6 km downstream of PAM addition, while PAM5 and PAM10 treatments produced > 2 mg L(-1) drain water polyacrylamide concentrations. We concluded that, although PAM practically eliminates Imperial Valley tailwater sediment loads, it does not effectively reduce tailwater Ps, the P fraction most responsible for the eutrophication of the Salton Sea.

Polyacrylamide in Agriculture and Environmental Land Management

“…In recent years, public concern has mounted for the impacts of return flows on algae growth and eutrophication in the Salton Sea. Goodson et al (2006) conducted a series of tests using continuous application of 1-, 5-, or 10-ppm PAM to irrigation water. The 1-ppm PAM treatment reduced turbidity 74% and total suspended solids 82%.…”

Adhesion of Escherichia coli and Salmonella enterica to Soil in Runoff as Influenced by Polyacrylamide

“…An alternative and potentially synergistic approach to reduce runoff involves the application of polymers such as the anionic polyacrylamide (PAM) to soil, which has been shown to reduce soil erosion by up to 84% Sojka, 1994, 2009;Zhang and Miller, 1996;Sepaskhah and Shahabizad, 2010;Tümsavaş and Kara, 2011). In addition, PAM has reduced the environmental impact of agricultural activities by reducing particulate phosphorus (Goodson et al, 2006), total phosphorus, fecal coliform bacteria , biochemical oxygen demand, and nitrate Sojka, 1994, 2000;Aase et al, 1998;Goodson et al, 2006) in runoff water. Polyacrylamide has been used as a soil-stabilizing compound since 1995 and is recommended by the NRCS for agricultural purposes.…”

Managing Runoff Water Quality from Recently Manured, Furrow‐Irrigated Fields

“…A number of researchers have evaluated the use of watersoluble anionic polyacrylamides (WSPAM) to improve runoff water quality from treated irrigation furrows Meral et al, 2004;Goodson et al, 2006;Oliver and Kookana, 2006;Szögi et al, 2007), although results have been inconsistent. A buried lateral furrow irrigation system is a gravity-based alternative to conventional furrow irrigation (Worstell, 1976(Worstell, , 1979.…”