Evaluation of performance and management strategies for a nursery irrigation recycling system designed for pollution control

Scope and method of study. The scope of this study was to evaluate, during both storm and non-storm events, the performance and management strategies of a nursery irrigation recycling system designed for pollution control. One objective of the study was to assess the overall performance of eight (8) on-site retention basins as a means to minimize offsite discharges of nutrient-enriched water during storm events. Another objective was to prepare an interactive model of a recycling irrigation system to evaluate water strategies for pollution control for storm and non-storm conditions. Methods used to meet the scope and objectives included the collection and chemical analyses of surface water samples from the retention basins on a monthly basis for one year. Additionally, storm water discharge samples from the facility were collected during the same time period and chemically analyzed. The test results were used to determine spatial and temporal patterns in the water quality and to identify the factors and processes that influenced those conditions.;Findings and conclusions. Based on the test results, several first flushes containing high nutrient concentrations occurred at the site as a result of storm events. As such, an appropriate design to capture and recycle a storm's first flush should be included in a plant nursery's best management practice and pollution control program. Along with proper sizing, effective basin designs include direct by-pass via a curbing system and plug flow through long basins that parallel surface water flow. The two (2) analytical and interactive models prepared for this study are capable of modeling many site-specific parameters and evaluating various water management strategies. The storm model has other additional pollution management capabilities due to its ability to estimate storm water runoff volumes and determine the height of freeboard needed in select basins. The system, including the eight retention basins and an irrigation recycling system, proved to be an effective pollution control technology and best management practice for a plant nursery.