Enhancement and Application of Minnesota Dry Swale Calculator

Principal Investigator:

John Gulliver, Professor, Civil, Environmental and Geo-Engineering


  • John Nieber, Professor, Bioproducts and Biosystems Engineering

Project Summary:

Swales and/or drainage ditches for linear road projects have excellent potential for stormwater treatment. They can infiltrate water into the soil, filter sediments and associated pollutants out of the water, and settle solids onto the soil surface. The infiltration rate is a controlling factor for the water quality performance of swales. The researchers have developed a new method using multiple measurements to calculate the saturated hydraulic conductivity (Ksat) of a swale. They have been applying this field method to quantifying the spatial distribution of saturated hydraulic conductivity in swales. Infiltration rate is a function of space, conditions before the storm, and conditions during the storm. However, there needs to be an alternative technique to estimate existing swale performance when there is better information available. This project aims to 1) develop a web-based model for estimating saturated hydraulic conductivity of a soil in a swale based on a point measurement of infiltration, calculation of an effective saturated hydraulic conductivity for an entire swale based on the spatial variation of estimated pointwise saturated hydraulic conductivity, and calculation of a curve number for the swale from the equivalent saturated hydraulic conductivity; 2) investigate the pattern of overland flow occurring along the side slope of a swale to better quantify the effective infiltration surface; 3) refine and further verify/develop a technique using the Green-Ampt assumptions and/or curve number to transition from the basic parameter Ksat to infiltration rate under wet, normal, and dry conditions, 4) develop a dry swale calculator that will use soil data to provide a Green-Ampt model or curve number model time-varying infiltration rate, 5) provide case studies on how to implement the enhanced calculation technique for comparison to the dry swale calculator, and 6) verify the enhanced dry swale procedure through the use of swale runoff field measurements.


Project Details:

  • Start date: 09/2013
  • Project Status: Completed
  • Research Area: Environment and Energy
  • Topics: Environment