Houlton Farm Planning Committee Meeting 2016-02-02

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WATER RESOURCES Surface Waters - Rivers The Elk and Mississippi rivers are the obvious surface water resources in this area. The Orono Dam controls water flow rates in this lower stretch of the Elk River. Following large rain events, especially in the spring, flows can be quite high. Since the river does not flood very much, the floodplain tends to be quite narrow, and it tightly follows the course of the river. Flood resistant vegetation would reflect this narrow band, with floodplain species not ranging out very far from the river channel. Therefore, prairie vegewould broadly occupy the uplands, and come very near the river valley. Fo a 'sissippi, the story changes somewhat. There are broad stretches of floodplain along the banks, and only in one stretch on the west side of the property does t ive almost adjacent to the existing farm field, which is elevated well about the ri a man a floodplain areas, standing water remains for long stretches of the ye Floodplain In 1965, an historic flood occurred throughout th classes so that male students could help sandbag local of the city. Water levels from this flood rose to cover n Houlton property. Today, more than half of the property is located within riverine cover much of the remaining area. Historically, erosion has not the south side of the prope least in the last century IVrVar recommended to prevent out of the water Buffer A 0"Of Elk River suspended shments and other key areas half of the farm fields at the iethe floodway and more a e 0.2% annual flood risk rty, save for the treeless bank on This bank was not vegetated (at i due to the natural bend in the inimum 50 -foot buffer is still p excess nutrients and other pollutants converted to prairie. The flo "n forest su iding the property acts as a natural buffer for the waterways. In areas w he forest i ider, is should provide very good water quality protection. Here, runoff he feel can settle before entering the river, and the forest in turn buffers the rest p erty from rapid changes in water levels. The buffer width on the south side of the p ty is much narrower. This area - along the Mississippi - is a treeless zone appr imately 800 feet in length, and agricultural production has occurred almost right up to the edge of the bank. There are some erosion gullies and outwash areas along the bank. Taking steps to control erosion here would be difficult. To a large extent, erosion along this bend is a natural process, though modern day increases in flooding frequency, duration and intensity no doubt have exacerbated historical erosion. Attempting to vegetate the bank as much as possible and increase the buffer size may help to reduce erosion and mitigate runoff into the river. Re -grading, stabilizing, and re -vegetating the degraded banks would be needed for more permanent and effective bank stabilization, but would be both intensive and expensive. Sherburne county Soil and Water Conservation Friends of the Mississippi W.H. Houlton Conservation Area ArRMP 29