PAM Field Experiments

TitleAuthor
Field Application of PAM to Water Delivery Canals R. Susfalk, D. Smith, B. Epstein, T. Gates, C. Martin

Research Description

Field Application of PAM to Water Delivery CanalsAlthough the application of granular PAM to a canal seems straight-forward, there are several factors that must be considered for a successful application. These factors include, but are not limited to, the type of soil, suspended sediment concentration, water temperature, water velocity, water chemistry, and the methods used to apply PAM. In general: 1) greater seepage reduction should occur in canal waters containing sufficient concentrations of divalent cations and finer-grained suspended sediments, and; 2) warmer water temperatures and lower water velocities should reduce the downstream distance that PAM can travel before it is reactive.

The objectives of these field applications are to: 1) assess how PAM is applied in order to maximize seepage reduction benefits and to minimize environmental impacts; 2) estimate the efficiency of PAM to alter seepage; and 3) monitor the downstream transport of PAM and AMD in the water column. The Research Consortium has applied or monitored the application of linear, anionic PAM to 13 canal reaches in Colorado and Montana through 2006. These canals have ranged in size from 3 cfs to over 800 cfs in size. Additional experiments are being conducted in eastern Colorado in 2007.

TitleAuthor
Assessing the Response of Aquatic Macroinvertebrates to PAM D. Sada and C. Rosamond

Research Description

Assessing the Response of Aquatic Macroinvertebrates to PAMAquatic systems support a wide diversity of life that is influenced by environmental conditions. A number of studies examining relationships between aquatic benthic macroinvertebrate (BMI) communities and characteristics of their environment show that differences in the structure of BMI communities is reflective of conditions in the aquatic environment. DRI will examine BMIs in specific reaches of irrigation canals as a means to: (1) compare the structure of pre and post-treatment benthic communities in treated and untreated reaches of a small irrigation canal, and (2) assess the effect of PAM on the structure of drifting macroinvertebrates during treatment in a canal. The goal will be to link the predictions of fate and transport with the effects on BMIs in canals and receiving waters. Effects of PAM on BMI communities will be determined following standard bioassessment protocols with taxa identified to the lowest possible taxonomic level.

TitleAuthor
Test Troughs R. Susfalk, B. Epstein, M. Schmidt, B. Fitzgerald, and J. Goreham
Test Troughs

Research Description

The Test Troughs (TTs) are a meso-scale flume facility consisting of two 24 m long, 10 cm deep furrows formed in ASTM C-33 sand. Water inflow pumped from the adjacent canal at 70 L/min, outflow, and seepage were continuously measured.

The objective of the TTs was to provide a semi-controlled environment in which the ability of PAM to affect short-term seepage rates could be measured. Seepage rates were measured directly and experiments lasted from 1 to 3 days in length. Parameters that were studied included PAM application rate, length of application, the hydration state of the applied PAM, and turbidity. PAM could be applied to either a dry or flowing TTs in either a partially-hydrated, granular, or dissolved form.Test Trough

Located in Grand Junction, CO, the TTs were built by and operated with the assistance of Max Schmidt and the Grand Valley Irrigation Company.

TitleAuthor
Aquatic Macroinvertebrate Response to PAM Application D. Sada and C. Rosamond

Aquatic Macroinvertebrate Response to PAM ApplicationResearch Description

Although PAM may benefit water management, there is little information to assess the environmental consequences of its application to aquatic ecosystems. Information about its potential effects are limited to studies examining anionic and other forms of the polymer that found it could affect some protococcal algae, invertebrates and adult fish. Artificial troughs were used to assess the effect that PAM, applied at a rate of 40 lbs/acres, had on riffle benthic communities and their drift. Differences in pre- and post-PAM benthic communities and in drift rates during application would suggest that macroinvertebrates are detrimentally influenced and that further work is necessary to determine the proximate and ultimate effects of this polymer on natural systems.