About Drainage Districts

Iowa Drainage Laws

Production and Environmenal Benefits of Drainage

It is estimated that more than 9 million acres of of the state of Iowa are drained which constitutes almost 26% of the state's land mass. There are more than 3,700 drainage districts state-wide, most of which are located in north central and northwest Iowa. Because of our incredibly flat terrain, there is an abundance of drainage districts located in Monona County. And, because of our predominantly agricultural economy, they are an essential part of our landscape. The positive impact of drainage is seen in many ways:

• Increased Yields - Research varies as to how much of an increase there is. A comprehensive 20-year study done in Canada showed a 29% average increase in corn yields on tiled vs. non-tiled land and a 26% increase in soybean yeilds. A 10-year study in Ohio showed a corn yield increase due to drainage of 40 bushels per acre.
• Plant roots receive enough oxygen to mature properly.
• Soil surface temperatures are increased which helps seeds germinate.
• Plants roots are grown deeper into the soil so they can absorb more nutrients.
• Water damage to public roads is inhibited.
• Storm water runoff is absorbed and downstream flooding is reduced.
• The chances of water-bourne 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.
• Crop loss due to drowning is decreased.
• 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.
• Soils 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.
• Promotes energy-conserving efficient farming practices and facilitate no-till and conservation tillage methods.
• Reduces losses of sediments, phosphorus, ammonium-nitrogen, pesticides, micro-organisms and antibiotics

The Iowa Drainage District Association (IDDA) provides legislative and funding support to Iowa drainage districts.

IDDA Website