Though compost specifications are one component in the complex design of LID systems, compost amendments have the potential to dramatically alter stormwater treatment potential. Optimal compost specifications will increase nutrient retention and infiltration rates, but overapplication or poor source selection will result in high nutrient export.  

The goal of this study is to determine the optimal source and application rate of compost amendments in local soils for maximizing water use efficiency and reducing runoff and groundwater quality impacts in semi-arid landscapes to support and improve technical guidelines for LID in Utah.   

Project objectives: 

1)     Characterize the potential effects of compost sources and application rates on soil hydrologic properties and water quality in native soils to determine an optimal compost-soil mixture. 

2)     Evaluate the effects of the designed compost-soil mixture on plot-scale hydrology and water quality during sequential simulated storm events with extended intermittent dry periods.  

3)     Develop cost-effective compost source and application rate specifications for optimized use of compost amendments in vegetated filter strips throughout Utah and determine suitable supply and procurement of compost products. 

Selecting vegetation for LID presents many challenges in arid and semi-arid climates. Vegetation facilitates reducing the volume and impact of stormwater runoff through surface stabilization, runoff volume reduction, and water quality improvement. Resilient vegetation with deep rooting is essential to achieving these stormwater goals: Deep roots may provide additional structural support for soils and penetrate the pressure barrier that often occurs at the interface between surface soils and embankment soils and limits infiltration to deeper soils. The use of wildflowers as alternative vegetation cover along roadside filter strips may provide a suite of co-benefits, including increased stormwater runoff infiltration and filtration, improved vegetation establishment and drought tolerance, reduced need and cost for maintenance activities, and increased habitat for pollinators.  

The goal of this study is to study the response of wildflowers to different soil types and levels of soil compaction and select the highest performing species for stormwater treatment in Utah soils and climate. 

Stormwater management traditionally routes stormwater runoff through a piped conveyance system in which runoff is carried through constructed subsurface drainage systems and discharged to a nearby waterbody. Research has long shown the drawbacks of piped stormwater conveyance; runoff picks up contaminants and pollutants from urban surfaces, and high runoff volumes are quickly drained to waterbodies, leading to pollution and degradation of waterways. Best management practices (BMPs) are implemented to treat stormwater before it enters storm drains or waterbodies to slow the flow of runoff and filter out pollutants. Stormwater conveyance channels are a common BMP for transporting stormwater runoff. Typically, conveyance channels are designed and constructed specifically for stormwater conveyance and generally have a limited ability to remove pollutants such as nutrients, bacteria, biological oxygen demand, and sediment.  

Many formerly small cities in the Intermountain West still utilize irrigation canals that channel water from natural rivers through the city in constructed, open-air canal systems. As these cities develop, they generally also utilize the canal system for stormwater conveyance. In these cases, canal systems operate as an informal conveyance channel. However, it is unknown how stormwater moves through canal systems, and if (and to what degree) the canal system provides treatment for urban stormwater runoff. The goal of this study is to track runoff volume and pollutant transport through a canal conveyance system in Logan, Utah to understand if the canal system provides treatment potential for the city’s stormwater runoff.