Facts about drainage and drainage districts
1) What is drainage?
Drainage is the removal of water from the soil profile by natural or artificial means. Drainage uses underground pipes and open ditches to carry water away from cropland during periods of excess moisture.
2) What are drainage districts?
Natural drainage outlets are not always
available or accessible for all lands that need them in a particular watershed.
Use of a natural outlet that is adequate in capacity and depth to carry
the runoff may require the extension of drainage outlets into land owned by
others. These other landowners may
benefit from these types of extensions.
Similarly, a system of levees is often required to protect land from
flooding. Drainage districts provide
a legally organized means to construct and maintain adequate drainage outlets
and levees. According to
3) How are drainage districts formed?
Two or more contiguous landowners can
petition the respective
4) Who manages drainage districts?
5) Who pays for drainage districts?
Lands within the confines of an established drainage district can be assessed for the construction, maintenance and repair of drainage district facilities. Assessments are based on the relative benefits received and may be spread over several years.
How many drainage
districts are there in
There are more than 3,000 districts in the
state. Most are located in north
central and northwest
How much of
It is estimated that more than 9 million acres of the state are drained. That would constitute almost 26% of the state’s land mass. 9 million acres is larger than the combined land mass of the states of Massachusetts, Connecticut and Rhode Island.
What is the Iowa
Drainage District Association?
IDDA is a private, non-profit
organization existing solely for the benefit and protection drainage districts.
IDDA is incorporated with the state of
9) Where in the
The drainage statutes are quite extensive and cover almost 75 pages of the Code book. The drainage statute is Chapter 468. Also, the state apparently saw the importance of agricultural drainage early in the 20th century as there was language added to the constitution on drainage. Article I, Section 18 of the Iowa Constitution states that “The general assembly, however, may pass laws permitting the owners of lands to construct drains, ditches and levees for the agricultural, sanitary or mining purposes across the lands of others, and provide for the organization of drainage districts, vest the proper authorities with power to construct and maintain levees, drains and ditches and to keep in repair all drains, ditches and levees heretofore constructed under the laws of the state, by special assessments upon the property benefitted thereby. The general assembly may provide by law for the condemnation of such real estate as shall be necessary for the construction and maintenance of such drains, ditches and levees, and prescribe the method of making such condemnations.” This constitutional provision was added in 1908.
10) Do all drainage districts use gravity solely as a means for moving water?
No, there are other districts in southeast
11) What about districts that have land in more than one county – how are they managed?
In such cases, district management decisions would be made by both county boards of supervisors acting jointly. In essence, the two county boards would become one for drainage purposes. For ease of administration, a “lead” county is usually designated.
12) How long have drainage districts been in existence?
Most of the drainage district statutes were written in the early 1900’s and the creation of many of today’s districts followed close behind that. The long history of the districts is both a blessing and a disadvantage. It is a blessing in that drainage of land has given us decades of productive agriculture that would not have been possible without it. It is a disadvantage in that much of the drainage infrastructure is very old and will have to be replaced – at substantial cost to the landowners in the district.
Production and Environmental Benefits of Drainage
yields – Research varies as to how much of an increase there is.
A comprehensive twenty year study done in
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-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
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.
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.
Promotes energy-conserving efficient farming practices and facilitates no-till and conservation tillage methods
Reduced losses of sediments, phosphorus, ammonium-nitrogen, pesticides, micro-organisms and anti-biotics