Drainage District Report
According to Iowa Drainage Law – “The drainage of surface waters from agricultural lands and all other lands or the protection of such lands from overflow shall be presumed to be a public benefit and conducive to the public health, convenience and welfare.” Drainage Districts are a legally organized method to construct and/or maintain adequate drainage outlets or levee embankments to protect lands from flooding. Over the past century nearly 3,700 drainage districts have been established in the state of Iowa, and are governed by Iowa Code Section 468.
The Drainage Department is comprised of the appointed Drainage Engineer and supporting staff members. The Department serves the 159 Drainage Districts established within Buena Vista County. These Districts are under the jurisdiction of the Buena Vista County Board of Supervisors, acting as trustees. The office will perform a variety of tasks for the continued maintenance and proposed improvements of these facilities.
The Department is shared with Calhoun and Sac Counties. Information regarding Drainage Districts in these additional counties can be obtained by request. The following is a list of benefits to providing adequate drainage to agricultural lands.
- Increased yields – Research varies as to how much of an increase there is. A comprehensive twenty-year study showed a 29% average increase in corn yields on tiled versus non-tiled land and a 26% increase in soybean yields. Another ten-year study showed a corn yield increase due to drainage of 40 bushels per acre.
- Plant roots receive enough oxygen to mature properly and grow deeper into the soil so they can absorb more nutrients.
- Soil surface temperatures are increased which helps seeds germinate.
- Storm water runoff is absorbed and downstream flooding is reduced.
- The chances of water-borne diseases are reduced.
- Since the soil can absorb and store more rainfall, runoff from the soil surface is reduced. Thus, soil erosion is reduced.
- Since fields dry out more quickly with drainage, the number of days available for planting and harvesting crops is increased.
- Land values are increased.
- Soil structure is improved. Soil needs to be drained to avoid soil compaction and structural damage, both of which reduce yields.
- Soil bearing strength is increased. The bearing strength of soil depends on its water content which in turn is affected by the depth of the water table. Good soil drainage increases soil strength and reduces damage caused by farming operations.
- Reduced losses of sediments, phosphorus, ammonium-nitrogen, pesticides, micro-organisms and antibiotics.