Many of the rural drainage systems in Minnesota were built in the 1900s and are reaching the end of their useful life. Chronic flooding in the farm fields is washing crops away and hurting the yields for the farmers. With more than 10,000 public systems in Minnesota, many farmers are facing the dilemma of putting significant investment into renewing the drainage systems. Traditionally such systems were designed using simple methods without sophisticated engineering modeling. Not many people questioned that practice until a young engineer started looking for a better way.
Growing up in a small rural town with about 3,000 people, Jacob fell in love with rural drainage design not too long after he started at ISG in 2015. Knowing many of the farmers in person and the struggles they were facing, Jacob was determined to find a better engineering solution to this challenge.
Around 2017, Jacob and his colleagues started to notice some recently built ponds were only half full during their design storm event. This led them to search for a better engineering approach that would not significantly “over-design” the system.
That effort led to two discoveries: XPSWMM and Drones. By switching to XPSWMM, Jacob can model the overland flow in 2D, allowing him to watch water flow in a farm field using the high-resolution LIDAR data. By deploying drones to take footage right after a storm event, Jacob can have high-resolution flood extent footage, and use it to calibrate the model. The video below is a system that was flown shortly after a large storm event which confirmed what the modeling was showing.
The combination of the two new technologies generated beautiful results. Now, Jacob can design new systems with much higher confidence and know he is saving the farmers' money by correctly sizing the system.
As shown in the figure above, a drone crew is flying an open ditch to determine if there is any sediment accumulation within the channel as well as ditch bank failures. The channel above shows vegetation within the channel that restricts the capacity and can cause additional flooding within the system.
During the selection process of XPSWMM, ISG created a comparative model and discovered that some storage areas were over-designed for the system. As shown in the figure above, using XPSWMM the size of the pond was reduced from 2.5 acres to 1.5 acres, and the excavation from 18000 cy to 13200 cy. This saved the landowners approximately $25,000 in construction and land acquisition costs.
Jacob can create animations like this in just a few clicks, and his farmer clients can immediately see how the proposed design will solve their problems.
As shown in the figure above, with XPSWMM Jacob can easily create maps showing the duration of the flooding. Farmers are especially interested in standing water longer than 48hr, as most crops will experience stress and may not survive such flooding. Maps like these can help farmers easily make important decisions without knowing too much about drainage design.