POLK SOIL AND WATER
CONSERVATION DISTRICT
SOIL AND WATER 5 YEAR RESOURCE
CONSERVATION PLAN
June 2013
COMMISSIONERS
ASSIST COMMISSIONERS
Dan Beougher
Jane Clark
Chip Mathis
Sherrie Taha
Cindy Valin
Elaine Ilvess
Ray Meylor
Louise Moon
Russ Paul
Ryan Peterson
Lisa Walters
PREFACE
The Soil and Water Conservation District has responsibilities under state laws for
carrying out a countywide soil and water conservation program. Planning for the longterm conservation of our soils, water, and related resources is not a simple task; but is
a necessary process when orderly development and utilization of our natural resources
is expected.
The Polk County Soil and Water Conservation District recognizes that with constant
change, an operating strategy can seldom be long lasting and needs to be re-analyzed
periodically. The update of our long-range program will reflect our objectives and
priorities as we plan to meet the land and water needs of our people.
The commissioners of the Polk County Soil and Water Conservation District are
providing this program for all individuals, groups, and units of government. It is an
organized effort to protect our soil and water resources within the district. The second
purpose is that the plan should be the focus of long-range development of the district’s
soil and water resources, as well as the basis for budgeting and implementation.
Furthermore, this continuous process is easily updated and/or amended to fit the
needs of the citizens that the District serves.
The Polk County Soil and Water Conservation District commissioners appreciate the
cooperation in developing this long-range plan. First the Commissioners would like to
thank the representatives of the: Natural Resources Conservation Service (NRCS),
Farm Service Agency (FSA), Iowa Department of Agriculture and Land Stewardship
(IDALS), Division of Soil Conservation (DSC), Iowa Department of Natural Resources
(IDNR), Iowa State University Cooperative Extension Service, County Board of
Supervisors, Iowa Department of Transportation, U.S. Geological Survey, and the Iowa
Department of Economic Development.
Secondly, credit should go to those contributing to the input that produced the
objectives, goals, and priorities of this plan. These include: Polk County Conservation
Board, Isaak Walton League, Ducks Unlimited, Pheasants Forever, Sierra Club,
Audubon Society, Farm Bureau, Farmers Union, L.I.C.A. (Land Improvement
Contractor Association), Contractors, Extension Service, Iowa Wildlife Federation,
Farmers and other county REAP Committee members.
ORGANIZATIONS AND AUTHORITIES
The Polk County Soil and Water Conservation District was organized at the request of
local people interested in soil and water conservation. A charter was issued under the
provisions of the Code of Iowa, Chapter 467A (161A), on December 29, 1945. The
boundaries of the district and the county are the same.
The district is a subdivision of state government, governed by five locally elected
commissioners, who are elected on the General ballot and serve four year terms.
District commissioners are charged by the Iowa General Assembly with the restoration
and conservation of the soil, water, and related natural resources of the county. The
district receives support services from the Iowa Department of Agriculture and Land
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Stewardship (IDALS). Commissioners can appoint as many assistant commissioners
as they deem necessary.
Additional authorities have been given the soil and water conservation district since it
was founded in 1945. Some of these additional authorities are:
1. Sub-districts, (Chapter 161A, Sec. 13-41), of a soil and water conservation district
may be formed for the purpose of carrying out watershed protection and flood
prevention programs, but shall not be formed solely for the purpose of establishing
or taking over the operation of an existing drainage district.
2. The commissioners of the soil and water conservation district shall adopt
reasonable regulations, (Chapter 161A, Sec. 42-53), to establish a soil loss limit or
limits for the district and provide for the implementation of the limit or limits, and
may subsequently amend or repeal their regulations as they deem necessary.
Chapter 161A also provides for mandatory erosion control after due process.
3. The soil and water conservation district, (Chapter 161E), advises and consults with
counties and sub-districts upon the request of any of them or any affected
landowners, and is authorized to cooperate with other state subdivisions, or
instrumentalities and affected landowners, as well as with the federal government
or any department or agency thereof, to construct, operate, and maintain suitable
projects for flood or soil erosion.
4. Under Chapter 161E, the County Board of Supervisors can establish districts
having for their purpose soil conservation and control of floodwaters. The
establishment of these districts requires the approval of the soil and water
conservation district along with the Iowa Department of Natural Resources (IDNR).
This section includes the role of the district in representing the rural as well as
urban interests in the administration of the Erosion Control Law and other
programs in which the district is involved.
The basic urban concern of the district is to help urban areas with erosion control.
Consultative assistance is provided to both the cities and the county upon request.
Also, these authorities are within the Code of Iowa, Chapter 161B - Agricultural
Energy Management and Chapter 161C - Water Protection Projects and Practices.
However, the ultimate responsibility for soil erosion control rests with the district.
District commissioners are authorized to request assistance from and enter into
Memorandums of Understanding between themselves and other federal, state, and
local entities to carry out their assignment and leadership role in the conservation,
development, and productive use of the county’s soil, water, and related resources.
Active Memorandums of Understanding have been signed with:
U.S. Soil Conservation Service
U.S. Soil Conservation Service
IA Agricultural Extension Service
IA Agricultural Extension Service
and Home Economics
U.S. Department of Agriculture
Polk County Board of Supervisors
U.S. Soil Conservation Service
5-25-46
9-19-49
10-24-57
8-01-63
1-26-65
3-09-65
9-26-67
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Central Iowa Regional Association of
Local Government
U.S. Army Corp. of Engineers
Skunk River Conservancy District
DSM River Conservancy District
Des Moines Schools
City of Des Moines
City of Polk City
U.S. Soil Conservation Service
U.S. Soil Conservation Service
Red Rock Resource Council
U.S. Soil Conservation Service
Polk County ASCS and CCC
U.S. Soil Conservation Service
U.S. Department of Agriculture
Food & Agriculture Council
1-16-74
3-25-76
6-17-76
6-17-76
8-19-76
8-04-77
7-17-78
7-19-82
6-16-87
9-18-90
7-14-92
7-15-94
11-4-96
4-15-05
The Polk SWCD has entered into the following 28E agreements:
Fourmile Creek Watershed Management
Authority
9-19-2012
The district also provides sponsorship and direction to programs administered by
other agencies that directly affect the operations and objectives of the district. In
addition, there are a number of agencies that have programs available that can assist
the district in carrying out its long range program and annual plan of work.
GENERAL DESCRIPTION OF THE POLK COUNTY DISTRICT
The total area of the district is approximately 592 square miles or 378,800 acres.
Roughly 96.6% of the total acres in the district are land, and the other 3.4 % is in
water.
The north and east half of the district is mainly farmland. The majority of the prime
farmland in the district is located in these areas. The City of Des Moines, which is
located in the south central part of the district, is the location of many major
companies. The State Capitol, as well as many other governmental agencies, is
located in Des Moines.
The metro area, which includes the surrounding communities of West Des Moines,
Urbandale, Clive, Ankeny, Johnston, Altoona, and Pleasant Hill, is the home for the
majority of the people who live in the district.
The 2012 estimated population of Polk County is 443,710, an 8.5% increase since
2006. The demographics of the Polk County district can be divided into three
distinctive groups. The first group is the percent of urban and rural people living
within the district. Ninety-nine percent of the residents of the district live in
incorporated areas, based upon the 2010 Census Bureau information. This then
leaves one percent of the district’s population in a rural setting of which many are
rural non-farms. The second group of our population is by percent of male and
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female. The population by gender in the district is 49.1 percent male and 50.9 percent
female, and the percent of the district’s operating units that are male are 80 per cent,
and female are 20 per cent. Thirdly, the district can be broken down by race
percentages. The percentages show 80.5 per cent White (Not Hispanic), 6.2 per cent
African American, 7.8 percent Hispanic/Latino, plus 4.3 per cent of others such as
Asian American, Native American, and other Pacific Islander, etc. The district’s farm
operating units are 98 per cent White, 2 per cent other such as African American,
Asian American, and Latino. See the Appendix A for Census Bureau population
charts. The median family income in the Polk County district is $57,473, which
compares to the State average of $50,451.
Agricultural tendencies of the Polk County district have seen a decrease in the number
of acres devoted to agriculture. The majority of the land in agricultural use produces
corn and soybeans. The acres used for pasture have steadily declined. Many acres
once used for pasture have been converted to other uses such as woodland, houses, or
cropland. The acres being planted to woodland have held steady. Livestock numbers
have declined. A majority of the cattle operations are located in the east part of the
district and are cow-calf operations on pasture.
In recognition of the significance of healthy soils on soil retention, flood mitigation,
moisture availability during drought conditions, and the retention and availability of
nutrients such as N, P, and K for crop production and maintenance of clean lakes and
rivers, a major focus of the Polk County Soil and Water Conservation District will be
on improving soil and water quality. Over the last 5 years Polk County has
experienced high rainfall and flooding for 2 years as well as one year of drought. The
Polk district will focus efforts on installing practices over all landuses that improve soil
health and quality as a way to manage water and the extreme weather conditions. The
district has been promoting the installation of infiltration based practices as a way to
manage stormwater in the urban landscape. The district will promote the use of notill/strip-till and cover crops to improve our soils health and improve stormwater
management and water infiltration in the rural area.
The number of acres within the district that are specifically used for row crops based
on 2011 data is 171,000 acres or approximately 45 percent. Also, 25 percent of these
acres are designated Highly Erodible Land under the Food Security Act. The following
table shows the trend of major crops.
ACRES IN PRODUCTION
Corn
Soybeans
Oats
Hay
TOTAL
1956
86,307
44,586
37,558
24,289
192,740
acres
acres
acres
acres
acres
1981
117,000
92,800
6,000
13,200
229,000
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acres
acres
acres
acres
acres
1989
100,000 acres
79,200 acres
11,500 acres
6,400 acres
197,100 acres
2011
100,000 acres
71,000 acres
500 acres
8,000 acres
179,500 acres
The acres that are currently used for pasture are approximately 7,000. There are also
1,000 acres that are used to produce Christmas trees and other trees for sale.
Another 500 acres are used to grow vegetables and over 300 acres of sod production.
Urban usage of land within the district is roughly 37.5 percent or 142,000 acres. This
is the portion of land area designated as part of a town or city equal to or exceeding a
population of 2,500.
Area with contracts in the Conservation Reserve Program (CRP) in the district is
approximately 3.0 percent of the total cropland acres, or 4,878 acres. Currently there
is 5,817 acres enrolled in the Wetland Reserve Program, Emergency Wetland Reserve
Program, and the Emergency Watershed Protection Program.
Land use trends over the past 20 years have shown a shift of land from agricultural to
nonagricultural uses. The urban expansion has occurred in the metro area
surrounding Des Moines. The expansion has increased the greatest to the area west
of Des Moines. However, the urban growth has also increased greatly around the
Ankeny and Johnston area, and more recently around Altoona and Pleasant Hill.
There has also been an increase in housing developments as well as single family
acreages being built in the south and eastern rural part of the district. All of the
development has converted land that once was used for agriculture. The Polk County
Comprehensive Land Use Plan and Zoning Ordinances will guide future development.
The Zoning Districts identified on the Zoning District map are designed to limit the
development of prime farmland. A copy of the map is in the district office. See
Appendix B for Article III County Ordinance on establishment of zoning districts and
zoning map.
The major bodies of water include Saylorville Reservoir, Big Creek Lake, Dale Maffit
Reservoir, Easter Lake, and Grays Lake. Major rivers and streams that follow through
the district include the Des Moines River, Raccoon River, South Skunk River, Indian
Creek, Big Creek, Beaver Creek, Walnut Creek, and Four Mile Creek. Of the above
mentioned bodies of water, rivers, and steams, the Raccoon and Des Moines Rivers are
used as primary sources of public drinking water. The other major sources of drinking
water serving the district are rural water systems and private and municipal well
water. The number and location of all private wells are unknown.
See Appendix C for a map of Polk County rivers, streams, and hydrologic units.
Ownership status of agricultural land within the district consists of two types. The
first type of ownership is the land that is owned by the person who uses or lives upon
it, which accounts for 33% of the land. The second type is land that is rented or
leased to another party, which accounts for 67% of the land.
INVENTORY OF SOIL, WATER, AND RELATED NATURAL RESOURCES
SOIL RESOURCES
Frequent reference will be made to the existing Polk County Soil Survey, completed in
2000. It will be the source for much of the soils data presented throughout this
section.
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Soil Resources Used for Agricultural Production
The soil resources used for agricultural purposes are 191,300 acres. Of this total, 52
percent is planted to corn, 37 percent to soybeans, 0.2 percent is seeded to oats and 4
percent is used as hayland. Based on surveys of cropland across the county, in 2000
approximately 13% of the corn and 23% of the soybeans were no-tilled. In 2002 the
amount of no-till corn increased to 22% but we have seen a steady decline to 8% in
2011. However, the amount of no-till soybeans continued to increase to a high of 36%
in 2008, but has also dropped back to 23% in 2011.The amount of cover crops used in
the county has been very small over the years. In the last year there has been
increased interest in the use of cover crops with a projected 600 – 800 acres planned
for 2013. Pasture is located on 4 percent of the total acres and 4.5 percent of the
agricultural land is in woodland. Loss of potential productivity caused by soil loss is a
concern on land used for agriculture. Excessive soil losses will limit production in the
future. The following explains the soil loss rates and time limits on reducing soil loss
for each agricultural use.
A. CROPLAND
Approximately 171,000 acres are used for the production of row crops such as corn
and soybeans. The amount of soil loss from these acres is affected by the erodibility of
the soil, the length and steepness of slopes, and the tillage systems used. Cropland
can be divided into the following groups. The soils in these groups have similar slope
length and steepness. The erosion rates and the time table for treatment varies with
each group. See Appendix D for a General Soil Map of Polk County.
Erosion Group I (0-2% slope)
The soils in this group include land capability classes I, IIw, and IIIw and are located
in areas 1, 3, and 5 on the general soils map. These soils are nearly level and
somewhat poorly drained to poorly drained. The majority of these 151,590 acres are
used for the production of corn and soybeans. Soil loss caused by water erosion is
minimal. Wind erosion can be excessive when crop residues are buried with tillage.
Soil loss based on Webster soil, 1% slope, 200 ft slope length. Cornstalks are fall
chiseled, soybean stubble is spring field cultivated. Wind erosion unsheltered distance
is 4,000 ft.
Water Erosion
Wind Erosion
TOTAL SOIL LOSS
1 ton/ac/yr
1 ton/ac/yr
2 ton/ac/yr
At this rate, we would lose 1" of topsoil in 77 years.
Currently the average depth of topsoil on these soils is 5 inches. At the soil loss rate
of 1" in 77 years, the soil would retain its current level of productivity for 385 years.
Erosion Group II (2-5% slope)
Approximately 92,392 acres of soils in this group include mostly land capability class
IIe and are in areas 1 and 8 on the general soils map. These soils are also cropped to
continuous row crop, usually a corn and soybean rotation.
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Soil loss based on Clarion soil, 4% slope, 200 ft. slope length. Cornstalks are fall
chiseled, leaving 30 percent residue. Soybean stubble is spring tilled to leave
20% residue after planting.
Water Erosion
Wind Erosion
TOTAL SOIL LOSS
2 ton/ac/yr
1 ton/ac/yr
3 ton/ac/yr
At this rate, 1" of topsoil would be lost in 50 years.
Currently, the topsoil thickness on these soils averages 4 inches. If another inch of
topsoil is lost the soil productivity will be reduced. At the soil loss rate 1" in 50 years,
these soils will retain their current productivity for 50 years.
Erosion Group III (5-16% slope)
Approximately 45,000 acres are used for production of corn, soybeans, oats, and hay.
These acres are considered Highly Erodible Land by definition of the Food Security Act
of 1985. The soils in this group are on general soils map areas 1, 2, 4, 6, 7, and 8 and
include Land Capability Classes IIIe and IVe. Approximately 36,500 of these acres are
used for continuous row crop. The remaining 8,500 acres are cropped to rotations that
would include oats and hay. The acres that are cropped to rotations, which include
oats and long term stands of hay, are considered to be adequately protected from soil
loss.
Soil loss based on Tama soil, 10% slope, 150 ft slope length, non-contoured.
Soybean stubble is spring tilled leaving 50% residue cover after planting corn.
Soybeans are no tilled into cornstalks leaving 80% residue cover after planting.
Water Erosion
Wind Erosion
Total soil loss
7 ton/ac/yr
0 ton/ac/yr
7 ton/ac/yr
At this rate, 1" of topsoil is lost in 22 years.
Currently, these soils are moderately eroded and only have 4 - 5 inches of topsoil. If
another 1.5 inches of topsoil is lost, the productivity of these soils will be reduced. If
current rates continue, this reduction will take place in 33 years.
B. PASTURE AND HAYLAND
Approximately 7,000 acres of agricultural land is used as pastureland. The majority
of the pastureland consists of bluegrass. Many wooded areas along rivers and streams
are also grazed. Approximately 4,000 acres are overgrazed and do not provide
adequate grass for summer months.
Gullies occur in the draws and often cut up the pasture and make the pasture hard to
manage. Many times these gullied pastures occur along rivers and streams. The silt
from these eroded gullies causes water quality problems down stream.
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Limiting grazing by establishing rotational grazing systems, as well as establishing
more productive grasses on these acres will improve ground cover and will protect the
soil and reduce gully erosion. Fencing livestock out of the streams and providing
alternative watering facilities also improves streams channels and banks.
There are also pastures that have become overgrown with Multi-Flora Rose and Honey
Locust. Once these species are established, they become unusable for livestock and
wildlife. We need to provide information and programs to manage these invasive
species.
C. WOODLANDS
There are approximately 8,600 acres of woodland. Approximately 60 % of these acres
are upland hardwoods such as oak and hickory. The remaining 40% of the woodland
are on the bottomland that consists of Elm, Soft Maple, Ash, and Cottonwood.
Approximately 3,000 acres of woodland are owned by private landowners and the
remaining acres are under public ownership.
The acres under private ownership could be managed to be more productive for timber
harvest, wildlife habitat, and erosion control. The acres being planted to new
woodland are increasing due to incentives such as the REAP program. Tax breaks
such as those provided under the Forest Reserve Program are often an incentive for
landowners to keep land in woodland.
D. SOIL RESOURCES FOR URBAN LAND
Approximately 165,000 acres of land in the district is in urban areas, roads, etc. The
cities in the metro area have expanded each year. Over the last 15 years over 2,150
acres of land per year is being converted from agricultural as well as other uses to
urban uses. See Appendix E for Polk County Agricultural Land Assessment table. Soil
loss occurs on these areas as they are being developed. Sediment that comes from the
developing areas can cause drainage problems in storm water drains as well as road
hazards if sediment is deposited in the roadways. Most cities require contractors to
install some form of erosion control. Most cities also require storm water detention on
developing areas. These standards, if used by all cities, would provide for erosion
control. The soil and water conservation district commissioners are responsible for
responding to soil loss complaints from all land users. The city of Des Moines is the
only city that has entered into a Memo of Understanding with the district. This
agreement allows the city of Des Moines to administer the soil loss control program on
Land Disturbing Activities. Most of the cities in Polk County have adopted soil erosion
ordinances to meet Phase I and II regulations. These cities are now developing post
construction ordinances to address stormwater management issues. See Appendix F
for information on these regulations and a listing of the cities.
E. GULLY EROSION
Gully erosion occurs whenever water runoff concentrates and flows over unprotected
soil. Gullies are more visible than sheet erosion. This type of erosion is not limited to
cropland. Gullies are common in overgrazed pasture, grazed woodland, as well as
urban land that is being developed. The soil loss caused by gully erosion can often
exceed 100 tons/acre. Gully erosion frequently exposes subsurface drainage tiles.
These tiles are more prone to damage caused by heavy farm equipment and damage
caused by freezing and thawing conditions.
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Approximately 3,000 acres of agricultural land are affected by gully erosion. To date
approximately 1,500 acres of gullies have been controlled by Grassed Waterways,
Water and Sediment Control Basins, and Grade Stabilization Structures. The
remaining 1,500 acres of gullies need to be controlled. As urban development occurs
and the amount of impervious surfaces increases, the increased runoff has caused
additional gully erosion and damage to infrastructure. The district is working with
city officials and developers to implement new infiltration practices on development
sites to reduce the stormwater runoff and gully erosion.
F. STREAM BANK EROSION
There are over 320 miles of rivers, streams, and creeks that flow through the Polk
District. Many of these rivers and streams have problems with stream bank erosion.
The control of this problem is difficult due to the cost and unproven effectiveness of
the treatments and the number of permits that are often required. In order to get a
permit, a landowner needs to have a plan developed. Due to this cost and lack of cost
share assistance, many landowners do not attempt to control these erosion problems.
Currently, the Army Corp. of Engineers, County Engineers, and the Iowa Department
of Natural Resources are the agencies that regulate these erosion control projects and
have authority to issue these permits. In many of the cities, the streams run through
individual homeowners property, which results in stream segments being maintained
at various levels and creates problems for maintenance access.
WATER RESOURCES
Water Quality
There are 100 miles of major streams in the district. The percentage of this total that
is located in urban areas is approximately 40%. The 60% that remain are located in
the rural setting. Streams that are considered major streams include the Des Moines
River, Raccoon River, South Skunk River, Indian Creek, Big Creek, Beaver Creek,
Walnut Creek and Fourmile Creek. For location of these rivers, see the map in
Appendix G.
The district’s current priority watersheds are: Camp, Fourmile, Easter Lake, and Big
Creek. The water quality of the Des Moines River and Raccoon River are of great
importance because they serve as the main drinking water source for the majority of
the people who live in the Des Moines Metro area. The Dale Maffit Reservoir is the
only lake that could also serve as a source of drinking water. The nitrate level in the
Raccoon River is a concern each spring. The Department of Natural Resources (DNR)
has determined the designated uses of each of the rivers, streams, and other major
bodies of water.
Wetlands in the Polk district will be protected to the fullest extent possible.
Approximately 1,000 acres of wetlands with buffers are enrolled in the Conservation
Reserve Program. Nearly 5,900 acres of permanent wetland easements have also been
established through the Wetland Reserve Program, Emergency Wetland Reserve
Program, and Emergency Watershed Program-Floodplain. Also, several areas are
enrolled as wetlands and are exempt from taxes under terms of the “Slough Bill”.
Wetland determinations on agricultural land have not been completed for all tracts of
land. Certified wetland determinations are being completed as requested by
producers.
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Ground Water Quality
There is concern about the quality of the ground water in rural areas. There is limited
data on the water quality problems of existing wells. The establishment of rural water
systems have overcome some of these problems. See Appendix H for a map of public
water supply wells and surface water intakes.
Water Quality - Non-point Source Pollution
The quality of the drinking water in the Des Moines area is a concern every spring
when the nitrate levels exceed the established limits. Nitrates appear to be from
several sources including agricultural land in the watershed. The application of
nitrogen to lawns in urban areas is also a source of nitrates. When applying nitrogen
fertilizer on rural and urban land, there needs to be consideration of the nutrient rate,
method of application, placement of nutrients, and the timing of application to ensure
proper nutrient management.
Soil loss from farmland and construction activities also contributes to the water
quality problems. The majority of the land in Polk County drains into the Des Moines
River. The Des Moines River drains into the Red Rock Reservoir. This reservoir has
lost storage capacity due to siltation. Although the land in Polk County is not the
main source of silt for this body of water, it certainly contributes to it.
RECREATION AND WILDLIFE RESOURCES
The federal, state, county, and city government manages land for recreation and
wildlife in Polk County.
The U.S. Army Corps of Engineers manages the largest of the recreation and wildlife
areas. The Saylorville Lake and surrounding areas take up approximately 13,000
acres of which 5,950 acres are water area formed by the Saylorville Dam. The pool
area of this flood control project is approximately 16,700 acres, which extends into
Dallas and Boone counties. The majority of the surrounding land is leased to the Iowa
Department of Natural Resources (DNR) and is managed for wildlife and public
recreation.
Big Creek Lake was created as a part of the Saylorville project. The 850 acre lake
protects Polk City from flooding. Big Creek Park, which is managed by the DNR, is a
part of 2,000 acres that are managed for recreation and wildlife.
The Polk County Conservation Board manages over 12,000 acres for wildlife and
recreation land. Nearly every city and town in the county has parks and recreation
areas. See Appendix I for locations and a listing of Polk County Conservation Board
and Des Moines Parks and Recreation areas.
There are approximately 4,850 acres of land enrolled in the Conservation Reserve
Program (CRP). The majority of the acres are seeded to cool season grasses, however,
more warm season grasses have been seeded in recent years on Continuous CRP sites.
The number of pheasants has increased as a result of these seedings.
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The Resource Enhancement and Protection Program (REAP) has provided extra needed
incentives for farmers as well as non-farm landowners to plant grasses and trees. This
program also provided the county and cities financial assistance to expand and
improve recreation and wildlife areas.
MINING AND MINERAL RESOURCES
Currently the main mineral resource is gravel. The County Engineering Department
has identified sources of gravel that could be used for transportation purposes such as
gravel roads. The gravel sources are of poor quality due to the high sand content.
Coal mines were operated in Polk County between 1865 and 1947. At peak
production in 1917, there were 222 coal mines in the Des Moines Metro area. By
1945 only four mines remained in operation and by 1947 the last mine located in the
Urbandale area ceased production.
The Iowa Geological Survey has located 160 of these original mines. The mines range
in size from a few square feet up to more than 1000 acres. The map included in
Appendix J shows the location of some of these mines. The location of these mines
needs to be considered in future commercial and residential development due to
potential land subsidence problems that can occur when these mines collapse.
LANDUSE AND LAND MANAGEMENT
Conservation practices are used to reduce soil losses to rates that the soil can tolerate
and still remain productive into the future. This tolerable rate or “T” value has been
set for all soil types in Polk County. The goal of the soil and water conservation
district is to assist landowners to apply soil conservation practices that will reduce soil
loss to “T”. It often requires the use of more than one soil conservation practice to
reduce soil loss to this level. A combination of practices or “resource management
systems” is often used. The practices in these systems will be as unique as the
landowner's objectives and the land to which it is applied. New stromwater
management practices are being promoted by the district to reduce urban runoff and
improve water quality. The Iowa Stormwater Management Manual is used as the
guide to design and install the new urban BMP’s.
FACTORS LIMITING PRACTICE APPLICATION
The following are limitations to getting conservation on the land. These are listed in
order of most limiting to least limiting.
Structural Practices
1. Lack of financial incentives
2. Lack of landowner knowledge of erosion
3. Shortage of available personnel for technical assistance
4. Length of construction season
5. Trained contractors
6. Absentee landowners
7. Urban development
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Management Practices
1. Landowner management of equipment and chemicals in a no-till and strip-till
system
2. Landowners awareness of the value of the soil that can be saved
3. Lack of education on feasibility and proper use of cover crops, nutrients, and
pesticides
4. Lack of education on the importance of improving soil health and quality
Grassed Waterways
1. Waterways are not shaped correctly. They are either too deep and narrow or too
flat and sediment builds up too quickly.
2. Seeding failures
3. Waterways are not maintained. Waterways are not mowed or the operator fails to
turn off sprayers when applying herbicides.
4. Lack of tile along and above waterway
Pasture and Hayland Management
1. Overgrazed pasture
2. Pasture that is not grazed and taken over by Multi-Flora Rose
3. Land users got out of the cattle business and there is insufficient incentive to get
back into business.
Woodland Management
1. Lack of information on woodland profitability and management for wildlife
2. Lack of lumber markets
3. Lack of financial incentives
Urban Practices
1. Lack of knowledge of erosion and stormwater problems and issues
2. Lack of DNR and city personnel to enforce pollution prevention plans on
development sites
3. Lack of information for developers and public on urban erosion and practices
4. Lack of knowledge of design engineers on new stormwater quality practices
5. Insufficient district urban conservation staff to provide assistance
Documentation
1. Lack of water monitoring data
2. Lack of funding for monitoring water and practice performance
3. Lack of staff for monitoring
LIST THE ACTIONS NEEDED TO OVERCOME THESE LIMITING FACTORS
Structural Practices
1. Make the best use of existing cost-share funds and request additional cost-share
funds when needed
2. Provide information and education programs on the benefits of controlling soil
erosion to farm and urban interest
3. Pursue local funding through the county to add personnel
4. Promote the incentive program for summer construction
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5. Train contractors on new or updated construction specifications
6. Inform and educate absentee landowners on the value and benefits of controlling
erosion on their property
7. Promote management and vegetative practices or other options to reduce erosion in
areas where structural practices are not wanted
Management Practices
1. Provide information and education programs on equipment options and chemical
use and safety
2. Provide information on soil health and quality
3. Provide incentives for landowners to try cover crops and provide information on the
financial benefits of cover crops, and nutrient and pest management.
4. Provide information on the benefits of improving soil health and quality such as
increased water infiltration, reduced runoff, and improved nutrient efficiencies.
Grassed Waterways
1. Provide waterway design information to landowners and contractors
2. Provide waterway seeding, mulching, and fabric check information to landowners
3. Provide waterway maintenance information to landowners
4. Encourage proper waterway drainage and grade stabilization structures for
adequate outlets
Pasture and Hayland
1. Encourage nutrient management, mowing, spraying, and rotational grazing
systems including mob grazing
2. Provide information to landowners on multi-flora rose control options
3. Provide landowners with alternative land use options for the property
Woodland
1. Provide information to landowners on better use and management of woodland
2. Work with District Forester to develop information on known lumber markets
3. Provide information to landowners of incentive programs for woodland planting and
improvement
Urban Practices
1. Notify owners of erosion problems when noted in the district and offer technical
assistance
2. Provide technical and planning assistance to units of government as requested
3. Develop informational materials to inform the public, developers, city officials, and
engineers on new stormwater practice benefits
4. Sponsor practice design workshops and tours to demonstrate urban practices to
engineers
5. Secure additional staff funding from Board of Supervisors and grant opportunities
Documentation
1. Develop a priority list of watersheds to assess and seek grants to include more
monitoring data collection
2. Seek alternative funding sources and include water and practice monitoring in
watershed project applications and work plans
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3. Coordinate monitoring activities with other groups and partners to spread out the
workload and share data
DISTRICT POLICIES
The following are the policies of the Polk County Soil and Water Conservation District.
1. The District will use a variety of activities and media to promote the district and
our programs to increase the public awareness of natural resource issues and
our services available to all county residents.
2. In the administration of the District programs, priority will be given to provide
assistance and implement practices on land in district designated watersheds
or areas.
3. We will not deny access to any programs and assistance from the district due to
race, color, national origin, age, disability, sex, gender identity, religion,
reprisal, political beliefs, marital status, familial or parental status, and sexual
orientation.
4. We will encourage all eligible people regardless of race, color, national origin,
age, disability, sex, gender identity, religion, reprisal, political beliefs, marital
status, familial or parental status, and sexual orientation to participate as
SWCD Board members and serve on SWCD committees.
5. All qualified applicants will be considered for employment regardless of race,
color, national origin, age, disability, sex, gender identity, religion, reprisal,
political beliefs, marital status, familial or parental status, and sexual
orientation.
6. All technical and financial assistance provided on soil and water conservation
practices will conform to the Natural Resources Conservation Service Technical
Guide and urban practices will follow the Iowa Stormwater Management
Manual and any other federal and/or state regulation.
7. The following conservation practices are listed in the order of high priority to
low priority for technical assistance.
a) No-till, Strip-till
b) Cover Crops
c) Grassed Waterways
d) Buffer Strips
e) Grade Stabilization Structures – may or may not impound water
f) Water and Sediment Control Basins
g) Terraces
h) Tree Planting and establishment of permanent grass cover
i) Streambank Stabilization
6. The soil loss limit levels used by the district are listed in the Natural Resources
Conservation Service Technical Guide.
7. The cost-share funds allocated to the district from Iowa Financial Incentive
Program (IFIP) will be used to control soil erosion on cropland. The following
conservation practices are listed in order of high priority to low priority for costshare funds.
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a) Soil Health: Currently up to 30% of the IFIP funds can be allocated to
management practices. The District will give priority to management
practices such as no-till/strip-till and cover crops to promote the
improvement of soil health and quality.
b) Grassed Waterways: To be eligible, 75% of the watershed above must have
erosion rates at or less than ‘T’ and 85% of the watershed area controlled by
the applying landowner must have soil loss at or below ‘T’.
c) Grade Stabilization Structure that may pond water
1. 75% of the watershed must have soil losses at or below ‘T’.
2. 85% of the applying landowner’s watershed area must have soil losses at
or below ‘T’.
d) Water and Sediment Control Basins: includes underground outlets.
e) Terraces: including necessary underground outlets. Equal consideration to
narrow-based, broad-based and grassed-back slope terraces. Lower priority
will be given to systems where no-till or conservation tillage would reduce
erosion to ‘T’ or less. Any application where the average ground slope within
a system exceeds 11 (eleven) percent will be given a lower priority. If an
application is for a continuation of a terrace system, even though the
average slope may exceed 11 (eleven) percent, the application will be
considered more favorably than if it were to initiate the system construction.
f) Critical Area Planting: practice must be permanent seeding. Any failure will
be corrected according to the terms of the maintenance agreement for the
project.
g) Pasture and Hayland Planting
8. Cost-share applications will be approved based on the district policies and
using a ranking sheet. The ranking sheet will include:
a) Location: designated watershed area
b) Practice: what practices is being planned
c) Project: multiple funding sources for project
d) Date: date the application was signed
See Appendix K for the ranking sheet.
Cost-share is set at 50% of the cost estimate or final bill, whichever is less.
Applicants can request additional funds with an amendment to the cost-share
application. Increases in cost-share funds on a project will be considered if
cost-share funds are available.
Cost-share funds will not be approved on land that is platted for development or
non-agriculture uses, except for new stormwater practices allowed under the
REAP practices funds.
Cost-share for special needs conservation projects will be considered by the
commissioners on an individual basis.
Cost-share policy will be reviewed and changed as needed.
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9. Private landowners with erosion problems in urban areas can request
assistance. Rural and Urban areas are shown on the Zoning District Map. The
Zoning Districts shown as the Agricultural Countryside District, Estates
District, and Suburban District, even though considered as rural, will be give
lower priority. All other areas will be considered as urban. Additional
assistance could be provided to urban areas if the district receives additional
staff. The district commissioners will encourage cities to establish and
administer their own erosion control ordinances. The district commissioners
will act on soil loss complaints filed in urban areas as well as rural areas, as
required by Iowa law. See Appendix L for the districts Urban Policy adopted on
October 18, 2005.
10. Landowners approved for cost-share projects that will assist with, or can
arrange for someone to assist with layout work, will receive first priority for
layout and design assistance.
11. Landowners who are approved for cost-share funds will be required to have an
approved conservation plan for the fields where the cost-share funds will be
used.
12. Landowners or their representative, NRCS technician, and contractor will meet
prior to construction to review specifications.
13. Contractors will be expected to do their own checkout work on completed
conservation practices that are approved with state cost-share funds. A copy of
the checkout notes will be provided to the NRCS office prior to payments of
state cost share-funds.
14. The district will publish an annual report each year to show the activities of the
district and how state funds were spent.
15. The district will prepare an annual work plan each year. The annual work plan
will show action items that will address limiting factors that are shown in the
District Soil and Water Resource Plan. The District Soil and Water Resource
Plan will be reviewed annually. This review will keep the plan up to date to
meet the changing resource conditions. This review could include updating the
limiting factors, adding or deleting action items, and modifying policy objectives.
16. The district commissioners will establish committees as needed to divide the
workload. The membership on these committees is not limited to the
commissioners or assistant commissioners. The commissioners will ask for
assistance from other groups and agencies to carryout action items in the
annual work plan.
17. The Polk Soil and Water Conservation District will enforce the terms of the
Maintenance/Performance Agreements completed with state cost-share funds.
Individuals (person or groups) wishing to amend a Maintenance/Performance
Agreement to remove permanent soil conservation practices, will be reviewed by
the soil and water conservation district commissioners, as follows:
NONCOMPLIANCE WITH MAINTENANCE/PERFORMANCE AGREEMENTS
Upon determinations by the district and the division that a landowner is not in
compliance with a maintenance/performance agreement, the division shall assist the
district in the issuance of an administrative order to the landowner requiring
appropriate maintenance, repair or reconstruction of the practice, provided voluntary
means have been exhausted. The district, in its sole discretion, may allow the
landowner or the landowner’s successors to refund the division the entire amount of
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the financial incentive payment received by the landowner in lieu of maintaining,
repairing, or reconstructing a practice.
a. Within 60 days from the date of issue of the administrative order, the
landowner shall submit to the district a written and signed statement of intent
to maintain, repair or reconstruct the practice.
b. The maintenance, repair or reconstruction work shall be initiated within 180
days from the date of issue of the administrative order and shall be
satisfactorily completed within one year of the date of issue of the
administrative order.
Agricultural land converted to nonagricultural land. If land subject to a
maintenance/performance agreement is converted to a nonagricultural use that does
not require a permanent soil and water conservation practice which has been
established with financial incentives, the practice shall not be removed until the owner
refunds the appropriate amount of the payment received.
a. Amount of refund. The amount of refund will be the amount of the financial
incentive payment received less 5 percent for each year the practice was in
place.
b. Districts will notify the division when such refunds are collected.
c. Refunds will be made to the division. The division will deposit refunds to the
appropriate district account. Use of the refunds will be limited to providing
financial incentives under this Chapter 10 of the Iowa Administrative Code.
DISTRICT OBJECTIVES, GOALS, AND PRIORITIES
District Mission: To provide leadership to help people improve, conserve, and sustain
our natural resources while educating them about the importance and practicality of
maintaining our environment and quality of life.
OBJECTIVE I
DISTRICT MANAGEMENT: Self-promotion and office administration.
GOAL 1: Increase the public awareness of the Polk SWCD and the services available.
Action Items:
a) Develop social media outlets such as website and facebook page.
b) Develop a quarterly newsletter and send to an electronic list to provide current
activity and program information.
c) Use the district logo and name on various media to promote the district.
d) Promote the district at shows, workshops, and events.
GOAL 2: Increase district program delivery capabilities.
Action Items:
a) Pursue local funding sources to expand district staff.
b) Pursue projects and funding to expand the staff and program availability.
c) Develop partnerships with other agencies, groups, and entities to expand
programs and staff.
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GOAL 3: Fulfill all office and program administration responsibilities.
Action Items:
a) Prepare and review office working plans regularly.
b) Administer all programs efficiently and equitably.
c) Attend commissioner meetings and training sessions to stay abreast of current
issues and activities.
OBJECTIVE II
SOIL RESOURCE OBJECTIVE: Protect and conserve soil resources for future
generations.
GOAL 1: Protect and conserve soil resources on cropland and pastureland.
Action Items:
a) Give priority to educating producers and promoting the benefits of installing
practices that focus on improving soil health.
b) Promote the use of cover crops to improve soil health and quality as well as
improved nutrient management.
c) Promote prescribed pasture management practices and incentives.
d) Review cost-share policy annually to be sure that cost-share funds are used to
achieve the most conservation with priority in designated project areas.
e) Inform the public on the new incentives such as the no interest loan program.
f) Give priority to cost-share projects that will be constructed during the summer.
g) Investigate the possibilities of county funds for conservation practices.
h) Find new ways to show landowners the importance of controlling soil erosion.
i) Continue to require contractor checkout. Consider policy that only projects
completed with contractor checkout will be approved for cost share funds.
j) Encourage contractors to perform layout of practices.
k) Provide information to landowners on the benefits of conservation tillage. Look
into tours, field demonstrations, and other means to get this message across.
l) Poll local landowners as to what type of information program would be most
effective.
m) Work with Co-ops or chemical representatives to incorporate common actions
that achieve their goals while protecting soil.
n) Demonstrate how grass buffer strips could be used to control soil loss and
reduce point rows.
o) Publicize how to properly shape, seed, and maintain grass waterways.
p) Send landowners information on how to maintain cost shared practices such as
terraces and basins after they have been completed.
q) Offer informational and educational workshops to the public.
r) Respond to soil loss complaints in a timely manner.
GOAL 2: Control soil loss on urban land.
Action Items:
a) Give priority to educating producers and promoting the benefits of installing
practices that focus on improving soil health.
b) Support efforts being made by Iowa legislators to require cities to have erosion
control standards.
c) Inform all cities and towns in the county about the Land Disturbing Activity
Regulations pursuant to Chapter 161A.64, Code of Iowa.
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d) Conduct training sessions for developers, contractors and city officials on
erosion control practices that could be used to control soil loss in urban areas
e) Encourage cities to establish erosion control standards that would be included
in the zoning ordinances.
f) Enter into 28E agreements with cities that establish more restrictive standards
than what is required by the Land Disturbing Activity Regulations.
g) Continue to review proposed plats that are being developed and comment on
the erosion control practices that are being planned.
h) Provide information to the public through various media and demonstration of
new stormwater management practices.
i) Respond to soil loss complaints in a timely manner.
j) Promote and utilize incentive funds to install practices with priority in
designated project areas.
GOAL 3: Reduce soil loss caused by streambank erosion.
Action Items:
a) Collect all existing information available on controlling streambank erosion and
which agencies need to be notified for permits. Streambank Stabilization book
and Riparian Zone information available.
b) Inform the public that streambank stabilization information is available.
c) Follow up on streambank stabilization projects that are completed and check to
see if they were effective.
d) Conduct assessments of streams and use RASCAL to document streambank
erosion areas.
e) Pursue additional funding incentives to implement streambank stabilization
practices.
f) Promote practices that limit livestock access to steams.
GOAL 4: Protect fields from soil loss as they come out of CRP.
Action Items:
a) Give priority to educating producers and promoting the benefits of installing
practices that focus on improving soil health.
b) Promote the benefits of CRP and encourage re-enrollment.
c) Inform Conservation Reserve Program participants on what assistance is
available. If not re-enrolling, develop a conservation plan that protects the
resources.
OBJECTIVE III
WATER RESOURCE OBJECTIVE: Protect the quality of surface waters of Polk
County.
GOAL 1: Reduce the use or make better use of chemicals and nutrients on urban and
rural land.
Action Items:
a) Contact Extension on what information programs currently exist on chemical
and nutrient use on urban land.
b) Work with lawn care services to incorporate common actions that achieve their
goals while protecting water resources.
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c) If the above items warrant it, request more controls by the legislature on lawn
care companies.
d) Inform the public to test soils and to monitor more closely what chemicals and
nutrients are put on their land.
e) Encourage landowners to scout their property and apply what chemicals are
needed, similar to Integrated Pest Management Programs.
f) Promote the use of incentive funds for nutrient management on agricultural
land.
g) Assist communities in the proper disposal of sludge from wastewater treatment
plants on agricultural land.
h) Promote installation of practices that reduce nutrient loss and focuses on
meeting the mission of the Iowa Nutrient Reduction Strategy.
GOAL 2: Protect surface waters from pollution caused by runoff from rural and
developing urban areas.
Action Areas:
a) After water sources and problems are identified, look at the best management
practices that are available to solve the problems.
b) Conduct resource assessments on watersheds throughout the county and
prioritize them for watershed project funding requests.
c) Submit watersheds for project funding.
d) Identify livestock operations that are located along rivers and streams that
could create water quality problems.
e) Use available programs for funding livestock management and stream access
practices.
f) Continue to promote urban conservation programs.
g) Contact DNR on urban development water quality problems.
OBJECTIVE IV
WILDLIFE AND RECREATION OBJECTIVES: Conserve, Enhance, and Protect Wildlife
Habitat.
GOAL 1: Identify existing wetlands and encourage their protection.
Action Items:
a) Complete wetland determinations as requested.
b) Inform landowners what incentives are available to protect wetlands.
c) Keep abreast of wetland preservation conservation agencies and groups on what
wetland preservation programs are available.
d) Encourage landowners to use the Slough Bill for tax exemption on wetlands.
e) Inform the public on successful wetland restoration projects and the benefits of
wetlands.
f) Inform developers on the requirements of FSA, DNR and the Army Corp. of
Engineers on the development of wetland areas.
GOAL 2: Expand the acres of land planted to trees.
Action Items:
a) Inform landowners on the benefits of planting trees.
b) Inform landowners on programs with available incentive funds for tree planting
projects.
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c) Publicize successful tree planting projects.
d) Work with partners and other entities that promote and offer incentives for tree
planting.
GOAL 3: Encourage the development of habitat.
Action Items:
a) Inform landowners of opportunities that promote the benefits of habitat.
b) Promote using incentive programs to implement more tree and prairie
plantings.
c) Publicize the benefits of successful habitat development.
d) Inform land users on habitat programs offered by other groups.
OBJECTIVE V
LANDUSE AND LAND MANAGEMENT OBJECTIVE: Assist decision makers on using
soil and water resources according to land capabilities.
GOAL 1: Preserve prime farmland for agricultural uses in rural areas.
Action Items:
a) Monitor land development plats to insure that prime farmland is protected.
b) Speak out at public hearings where public facilities such as airports, new
highways etc. threaten the preservation of prime farmland.
c) Keep current on systems such as Land Evaluation Site Assessment (LESA)
currently used to evaluate sites that use federal funds.
GOAL 2: Encourage the use of soil information in the planning and development of
areas for urban uses.
Action Items:
a) Request that communities use soil information in developing their Master
Plans.
b) Refer to soil information on plat reviews
GOAL 3: Provide county jurisdictions and residents with information on abandoned
mines to reduce the potential for land subsidence problems.
Action Items:
a) Remind jurisdictions to review the abandon mine map when reviewing proposed
development site plans to alert the developer of the potential subsidence issues.
b) Refer landowners with subsidence issues to the Mines and Minerals Bureau of
the DSC-IDALS and provide assistance as needed.
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STATEMENT OF ADOPTION
We, the Commissioners of Polk County Soil and Water Conservation District, adopt
this program on the ________ day of _________, __________.
________________________________
Chairperson
________________________________
________________________________
________________________________
________________________________
STATEMENT OF APPROVAL
This plan of the Polk Soil and Water Conservation District was reviewed and approved
by the Iowa Department of Agriculture and Land Stewardship, Division of Soil
Conservation on the ______ day of _____________, ____________.
________________________________
Director
Division of Soil Conservation
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