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Conservation practice standards are reviewed periodically, and updated if needed. To obtain 

the current version of this standard, contact the Natural Resources Conservation Service 

NATURAL RESOURCES CONSERVATION SERVICE 

CONSERVATION PRACTICE STANDARD 

WASTE STORAGE FACILITY 

(No.) 

CODE 313 

DEFINITION 

A waste storage impoundment made by 

constructing an embankment and/or excavating 

a pit or dugout, or by fabricating a structure. 

PURPOSE 

To temporarily store wastes such as manure, 

wastewater, and contaminated runoff as a 

storage function component of an agricultural 

waste management system. 

CONDITIONS WHERE PRACTICE APPLIES 

• Where the storage facility is a component of a 

planned agricultural waste management 

system 

• Where temporary storage is needed for 

organic wastes generated by agricultural 

production or processing 

• Where the storage facility can be constructed, 

operated and maintained without polluting air 

or water resources 

• Where site conditions are suitable for 

construction of the facility 

• To facilities utilizing embankments with an 

effective height of 35 feet or less where 

damage resulting from failure would be limited 

to damage of farm buildings, agricultural land, 

or township and country roads. 

• To fabricated structures including tanks, 

stacking facilities, and pond appurtenances. 

CRITERIA 

General Criteria Applicable to All Waste 

Storage Facilities.

Laws and Regulations. Waste storage 

facilities must be planned, designed, and 

constructed to meet all federal, state, and local 

laws and regulations. 

Location. To minimize the potential for 

contamination of streams, waste storage 

facilities should be located outside of floodplains. 

However, if site restrictions require location 

within a floodplain, they shall be protected from 

inundation or damage from a 25-year flood 

event, or larger if required by laws, rules, and 

regulations. Waste storage facilities shall be 

located so the potential impacts from breach of 

embankment, accidental release, and liner 

failure are minimized; and separation distances 

are such that prevailing winds and landscape 

elements such as building arrangement, 

landforms, and vegetation minimize odors and 

protect aesthetic values. 

Storage Period. The storage period is the 

maximum length of time anticipated between 

emptying events. The minimum storage period 

shall be based on the timing required for 

environmentally safe waste utilization 

considering the climate, crops, soil, equipment, 

and local, state, and federal regulations. 

Design Storage Volume. The design storage 

volume equal to the required storage volume, 

shall consist of the total of the following as 

appropriate: 

(a) Manure, wastewater, and other wastes 

accumulated during the storage period 
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Conservation practice standards are reviewed periodically, and updated if needed. To obtain 

the current version of this standard, contact the Natural Resources Conservation Service 

(b) Normal precipitation less evaporation on the 

surface area (at the design storage volume 

level) of the facility during the storage period 

(c) Normal runoff from the facility's drainage 

area during the storage period 

(d) 25-year, 24-hour precipitation on the surface 

(at the required design storage volume level) 

of the facility 

(e) 25-year, 24-hour runoff from the facility's 

drainage area 

(f) Residual solids after liquids have been 

removed. A minimum of 6 inches shall be 

provided for tanks 

(g) Additional storage as may be required to 

meet management goals or regulatory 

requirements 

Inlet. Inlets shall be of any permanent type 

designed to resist corrosion, plugging, freeze 

damage and ultraviolet ray deterioration while 

incorporating erosion protection as necessary. 

Emptying Component. Some type of 

component shall be provided for emptying 

storage facilities. It may be a facility such as a

gate, pipe, dock, wet well, pumping platform, 

retaining wall, or ramp. Features to protect 

against erosion, tampering, and accidental 

release shall be incorporated as necessary. 

Accumulated Solids Removal. Provision shall 

be made for periodic removal of accumulated 

solids to preserve storage capacity. The 

anticipated method for doing this must be 

considered in planning, particularly in 

determining the configuration of ponds and type 

of seal, if any. 

Safety. Design shall include appropriate safety 

features to minimize the hazards of the facility. 

Ramps used to empty liquids shall have a slope 

of 4 horizontal to 1 vertical or flatter. Those used 

to empty slurry, semi-solid, or solid waste shall 

have a slope of 10 horizontal to 1 vertical or 

flatter unless special traction surfaces are 

provided. Warning signs, fences, ladders, 

ropes, bars, rails, and other devices shall be 

provided, as appropriate, to ensure the safety of 

humans and livestock. Ventilation and warning 

signs must be provided for covered waste 

holding structures, as necessary, to prevent 

explosion, poisoning, or asphyxiation. Pipelines 

shall be provided with a water-sealed trap and 

vent, or similar device, if there is a potential, 

based on design configuration, for gases to enter 

buildings or other confined spaces. Ponds and 

uncovered fabricated structures for liquid or 

slurry waste with walls less than 5 feet above 

ground surface shall be fenced and warning 

signs posted to prevent children and others from 

using them for other than their intended purpose. 

Erosion Protection. Embankments and 

disturbed areas surrounding the facility shall be 

treated to control erosion. 

Liners. Liners shall meet or exceed the criteria 

in Pond Sealing or Lining (521). 

Additional Criteria for Waste Storage Ponds

Soil and foundation. The pond shall be located 

in soils with an acceptable permeability that 

meets all applicable regulation, or the pond shall 

be lined. Information and guidance on 

controlling seepage from waste impoundments 

can be found in the Agricultural Waste 

Management Field Handbook (AWMFH), 

Appendix 10D. 

The pond shall have a bottom elevation that is a 

minimum of 2 feet above the seasonal high 

water table unless features of special design are 

incorporated that address buoyant forces, pond 

seepage rate and non-encroachment of the 

water table by contaminants. The water table 

may be lowered by use of perimeter drains, if 

feasible, to meet this requirement. 

Maximum Operating Level. The maximum 

operating level for waste storage ponds shall be 

the pond level that provides for the required 

volume less the volume contribution of 

precipitation and runoff from the 25-year, 24-

hour storm event plus the volume allowance for 

residual solids after liquids have been removed. 

A permanent marker or recorder shall be 

installed at this maximum operating level to 

indicate when drawdown should begin. The 

marker or recorder shall be referenced and 

explained in the O&M plan. 

Outlet. No outlet shall automatically release 

storage from the required design volume. 

Manually operated outlets shall be of permanent 

type designed to resist corrosion and plugging. 
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Conservation practice standards are reviewed periodically, and updated if needed. To obtain 

the current version of this standard, contact the Natural Resources Conservation Service 

Embankments. The minimum elevation of the 

top of the settled embankment shall be 1 foot 

above the waste storage pond’s required 

volume. This height shall be increased by the 

amount needed to ensure that the top elevation 

will be maintained after settlement. This 

increase shall be not less than 5 percent. The 

minimum top widths are shown in Table 1. The 

combined side slopes of the settled 

embankment shall not be less than 5 horizontal 

to 1 vertical, and neither slope shall be steeper 

than 2 horizontal to 1 vertical unless provisions 

are made to provide stability. 

Table 1 – Minimum Top Widths 

Total embankment Top Width, 

 Height, ft. ft. 

 15 or less 8 

 15 – 20 10 

 20 – 25 12 

 25 – 30 14 

 30 – 35 15 

Excavations. Unless supported by a soil 

investigation, excavated side slopes shall be no 

steeper than 2 horizontal to 1 vertical. 

Additional Criteria for Fabricated Structures

Foundation. The foundations of fabricated 

waste storage structures shall be proportioned to 

safely support all superimposed loads without 

excessive movement or settlement. 

Where a non-uniform foundation cannot be 

avoided or applied loads may create highly 

variable foundation loads, settlement should be 

calculated from site-specific soil test data. Index 

tests of site soil may allow correlation with similar 

soils for which test data is available. If no test

data is available, presumptive bearing strength 

values for assessing actual bearing pressures 

may be obtained from Table 2 or another 

nationally recognized building code. In using 

presumptive bearing values, adequate detailing 

and articulation shall be provided to avoid 

distressing movements in the structure. 

Foundations consisting of bedrock with joints, 

fractures, or solution channels shall be treated or

a separation distance provided consisting of a 

minimum of 1 foot of impermeable soil between 

the floor slab and the bedrock or an alternative 

that will achieve equal protection. 

Table 2 - Presumptive Allowable Bearing 

Stress Values1 

Foundation Description Allowable 

Stress 

Crystalline Bedrock 

Sedimentary Rock 

Sandy Gravel or Gravel 

Sand, Silty Sand, Clayey 

Sand, Silty Gravel, Clayey 

Gravel 

Clay, Sandy Clay, Silty Clay, 

Clayey Silt 

12000 psf 

6000 psf 

5000 psf 

3000 psf 

2000 psf 

1 Basic Building Code, 12th Edition, 1993, 

Building Officials and Code Administrators, 

Inc. (BOCA) 

Liquid Tightness. Applications such as tanks, 

that require liquid tightness shall be designed 

and constructed in accordance with standard 

engineering and industry practice appropriate for 

the construction materials used to achieve this 

objective. 

Structural Loadings. Waste storage structures 

shall be designed to withstand all anticipated 

loads including internal and external loads, 

hydrostatic uplift pressure, concentrated surface 

and impact loads, water pressure due to 

seasonal high water table, and frost or ice 

pressure and load combinations in 

compliance with this standard and applicable 

local building codes. 

The lateral earth pressures should be calculated 

from soil strength values determined from the 

results of appropriate soil tests. Lateral earth 

pressures can be calculated using the 

procedures in TR-74. If soil strength tests are 

not available, the presumptive lateral earth 

pressure values indicated in Table 3 shall be 

used. 
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Chapter 2. Agriculture 2-136 

Conservation practice standards are reviewed periodically, and updated if needed. To obtain 

the current version of this standard, contact the Natural Resources Conservation Service 

TABLE 3 - LATERAL EARTH PRESSURE VALUES1 

Lateral earth pressures based upon equivalent 

fluid assumptions shall be assigned according to 

the following conditions: 

• Rigid frame or restrained wall. Use the 

values shown in Table 3 under the column 

“Frame tanks,” which gives pressures 

comparable to the at-rest condition. 

• Flexible or yielding wall. Use the values 

shown in Table 3 under the column “Freestanding walls,” which gives pressures 

comparable to the active condition. Walls 

in this category are designed on the basis of 

gravity for stability or are designed as a 

cantilever having a base wall thickness to height 

of backfill ratio not more than 0.085. 

Internal lateral pressure used for design shall be 

65 lb/ft2 where the stored waste is not protected 

Equivalent fluid pressure (lb/ft2/ft of depth) 

Soil Above seasonal high 

water table2

Below seasonal high water table3

Description4

Unified 

Classification4

Freestanding 

walls 

Frame 

tanks 

Freestanding 

walls 

Frame 

tanks 

Clean gravel, sand or 

sand-gravel mixtures 

(maximum 5% fines)5

GP, GW, SP, SW 30 50 80 90 

Gravel, sand, silt and 

clay mixtures (less than 

50% fines) 

Coarse sands with silt 

and and/or clay (less 

than 50% fines) 

All gravel sand dual 

symbol classifications 

and GM, GC, SC, SM, 

SC-SM 35 60 80 100 

Low-plasticity silts and 

clays with some sand 

and/or gravel (50% or 

more fines) 

Fine sands with silt 

and/or clay (less than 

 50% fines) 

CL, ML, CL-ML 

SC, SM, SC-SM 

45 75 90 105 

Low to medium plasticity 

silts and clays with little 

sand and/or gravel (50% 

or more fines) CL, ML, CL-ML 65 85 95 110 

High plasticity silts and 

clays (liquid limit more 

than 50)6

CH, MH - - - - 

1

 For lightly-compacted soils (85% to 90% maximum standard density.) Includes compaction by use of typical 

farm equipment. 

2

 Also below seasonal high water table if adequate drainage is provided. 

3

 Includes hydrostatic pressure. 

4

 All definitions and procedures in accordance with ASTM D 2488 and D 653. 

5 Generally, only washed materials are in this category 

6 Not recommended. Requires special design if used. 
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Conservation practice standards are reviewed periodically, and updated if needed. To obtain 

the current version of this standard, contact the Natural Resources Conservation Service 

from precipitation. A value of 60 lb/ft2 may be 

used where the stored waste is protected from 

precipitation and will not become saturated. 

Lesser values may be used if supported by 

measurement of actual pressures of the waste to 

be stored. If heavy equipment will be operated 

near the wall, an additional two feet of soil 

surcharge shall be considered in the wall 

analysis. 

Tank covers shall be designed to withstand both 

dead and live loads. The live load values for 

covers contained in ASAE EP378.3, Floor and 

Suspended Loads on Agricultural Structures Due 

to Use, and in ASAE EP 393.2, Manure 

Storages, shall be the minimum used. The 

actual axle load for tank wagons having more 

than a 2,000 gallon capacity shall be used. 

If the facility is to have a roof, snow and wind 

loads shall be as specified in ASAE EP288.5, 

Agricultural Building Snow and Wind Loads. If 

the facility is to serve as part of a foundation or

support for a building, the total load shall be 

considered in the structural design. 

Structural Design. The structural design shall 

consider all items that will influence the 

performance of the structure, including loading 

assumptions, material properties and 

construction quality. Design assumptions and 

construction requirements shall be indicated on 

standard plans. 

Tanks may be designed with or without covers. 

Covers, beams, or braces that are integral to 

structural performance must be indicated on the 

construction drawings. The openings in covered 

tanks shall be designed to accommodate 

equipment for loading, agitating, and emptying. 

These openings shall be equipped with grills or 

secure covers for safety, and for odor and vector 

control. 

All structures shall be underlain by free draining 

material or shall have a footing located below the 

anticipated frost depth. Fabricated structures 

shall be designed according to the criteria in the 

following references as appropriate: 

• Steel: “Manual of Steel Construction”, 

American Institute of Steel Construction. 

• Timber: “National Design Specifications for 

Wood Construction”, American Forest and 

Paper Association. 

• Concrete: “Building Code Requirements for 

Reinforced Concrete, ACI 318”, American 

Concrete Institute. 

• Masonry: “Building Code Requirements for 

Masonry Structures, ACI 530”, American 

Concrete Institute. 

Slabs on Grade. Slab design shall consider the 

required performance and the critical applied 

loads along with both the subgrade material and 

material resistance of the concrete slab. Where 

applied point loads are minimal and liquidtightness is not required, such as barnyard and 

feedlot slabs subject only to precipitation, and 

the subgrade is uniform and dense, the 

minimum slab thickness shall be 4 inches with a 

maximum joint spacing of 10 feet. Joint spacing 

can be increased if steel reinforcing is added 

based on subgrade drag theory. 

For applications where liquid-tightness is 

required such as floor slabs of storage tanks, the 

minimum thickness for uniform foundations shall 

be 5 inches and shall contain distributed 

reinforcing steel. The required area of such 

reinforcing steel shall be based on subgrade 

drag theory as discussed in industry guidelines 

such as American Concrete Institute, ACI 360, 

“Design of Slabs-on-Grade”. 

When heavy equipment loads are to be resisted 

and/or where a non-uniform foundation cannot 

be avoided, an appropriate design procedure 

incorporating a subgrade resistance 

parameter(s) such as ACI 360 shall be used. 

CONSIDERATIONS 

Waste storage facilities should be located as 

close to the source of waste and polluted runoff 

as practicable. 

Non-polluted runoff should be excluded from the 

structure to the fullest extent possible except 

where its storage is advantageous to the 

operation of the agricultural waste management 

system. 

Freeboard for waste storage tanks should be 

considered. 
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Chapter 2. Agriculture 2-138 

Conservation practice standards are reviewed periodically, and updated if needed. To obtain 

the current version of this standard, contact the Natural Resources Conservation Service 

Solid/liquid separation of runoff or wastewater 

entering pond facilities should be considered to 

minimize the frequency of accumulated solids 

removal and to facilitate pumping and application 

of the stored waste. 

Due consideration should be given to 

environmental concerns, economics, the overall 

waste management system plan, and safety and 

health factors. 

Considerations for Minimizing the Potential 

for and Impacts of Sudden Breach of 

Embankment or Accidental Release from the 

Required Volume.

Features, safeguards, and/or management 

measures to minimize the risk of failure or 

accidental release, or to minimize or mitigate 

impact of this type of failure should be 

considered when any of the categories listed in 

Table 4 might be significantly affected. 

The following should be considered either singly 

or in combination to minimize the potential of or 

the consequences of sudden breach of 

embankments when one or more of the potential 

impact categories listed in Table 4 may be 

significantly affected: 

1. An auxiliary (emergency) spillway 

2. Additional freeboard 

3. Storage for wet year rather than normal year 

precipitation 

4. Reinforced embankment -- such as, 

additional top width, flattened and/or 

armored downstream side slopes 

5. Secondary containment 

The following options should be considered to 

minimize the potential for accidental release 

from the required volume through gravity outlets 

when one or more of the potential impact 

categories listed in Table 4 may be significantly 

affected: 

1. Outlet gate locks or locked gate housing 

2. Secondary containment 

3. Alarm system 

4. Another means of emptying the required 

volume 

Considerations for Minimizing the Potential 

of Waste Storage Pond Liner Failure.

Sites with categories listed in Table 5 should be 

avoided unless no reasonable alternative exists. 

Under those circumstances, consideration 

should be given to providing an additional 

measure of safety from pond seepage when any 

of the potential impact categories listed in Table 

5 may be significantly affected. 

Table 4 - Potential Impact Categories from 

Breach of Embankment or Accidental 

Release 

1. Surface water bodies -- perennial streams, 

lakes, wetlands, and estuaries 

2. Critical habitat for threatened and 

endangered species. 

3. Riparian areas 

4. Farmstead, or other areas of habitation 

5. Off-farm property 

6. Historical and/or archaeological sites or 

structures that meet the eligibility criteria for 

listing in the National Register of Historical 

Places. 

Table 5 - Potential Impact Categories for 

Liner Failure 

1. Any underlying aquifer is at a shallow 

depth and not confined 

2. The vadose zone is rock 

3. The aquifer is a domestic water supply or 

ecologically vital water supply 

4. The site is located in an area of 

solutionized bedrock such as limestone 

or gypsum. 
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Conservation practice standards are reviewed periodically, and updated if needed. To obtain 

the current version of this standard, contact the Natural Resources Conservation Service 

Should any of the potential impact categories 

listed in Table 5 be affected, consideration 

should be given to the following: 

1. A clay liner designed in accordance with 

procedures of AWMFH Appendix 10D with a 

thickness and coefficient of permeability so 

that specific discharge is less than 1 x 10 −6

cm/sec 

2. A flexible membrane liner over a clay liner 

3. A geosynthetic clay liner (GCL) flexible 

membrane liner 

4. A concrete liner designed in accordance with 

slabs on grade criteria for fabricated 

structures requiring water tightness 

Considerations for Improving Air Quality

To reduce emissions of greenhouse gases, 

ammonia, volatile organic compounds, and odor, 

other practices such as Anaerobic Digester – 

Ambient Temperature (365), Anaerobic Digester 

– Controlled Temperature (366), Waste Facility 

Cover (367), and Composting Facility (317) can 

be added to the waste management system. 

Adjusting pH below 7 may reduce ammonia 

emissions from the waste storage facility but 

may increase odor when waste is surface 

applied (see Waste Utilization, 633). 

Some fabric and organic covers have been 

shown to be effective in reducing odors. 

PLANS AND SPECIFICATIONS 

Plans and specifications shall be prepared in 

accordance with the criteria of this standard and 

shall describe the requirements for applying the 

practice to achieve its intended use. 

OPERATION AND MAINTENANCE 

An operation and maintenance plan shall be 

developed that is consistent with the purposes of 

the practice, its intended life, safety 

requirements, and the criteria for its design. 

The plan shall contain the operational 

requirements for emptying the storage facility. 

This shall include the requirement that waste 

shall be removed from storage and utilized at 

locations, times, rates, and volume in 

accordance with the overall waste management 

system plan. 

In addition, for ponds, the plan shall include an 

explanation of the permanent marker or recorder 

installed to indicate the maximum operating 

level. 

The plan shall include a strategy for removal and 

disposition of waste with the least environmental 

damage during the normal storage period to the 

extent necessary to insure the pond’s safe 

operation. This strategy is for the removal of the

contribution of unusual storm events that may 

cause the pond to fill to capacity prematurely 

with subsequent design inflow and usual 

precipitation prior to the end of the normal 

storage period. 

Development of an emergency action plan 

should be considered for waste storage facilities 

where there is a potential for significant impact 

from breach or accidental release. The plan 

shall include site-specific provisions for 

emergency actions that will minimize these 

impacts.
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Conservation practice standards are reviewed periodically, and updated if needed. To obtain 

the current version of this standard, contact the Natural Resources Conservation Service 

NATURAL RESOURCES CONSERVATION SERVICE 

CONSERVATION PRACTICE STANDARD 

COVER CROP 

(Ac.) 

2 

CODE 340 

DEFINITION 

Crops including grasses, legumes and forbs for 

seasonal cover and other conservation 

purposes. 

PURPOSE 

• Reduce erosion from wind and water. 

• Increase soil organic matter content. 

• Capture and recycle or redistribute 

nutrients in the soil profile. 

• Promote biological nitrogen fixation. 

• Increase biodiversity. 

• Weed suppression. 

• Provide supplemental forage. 

• Soil moisture management. 

• Reduce particulate emissions into the 

atmosphere. 

• Minimize and reduce soil compaction. 

CONDITIONS WHERE PRACTICE APPLIES 

On all lands requiring vegetative cover for 

natural resource protection and or improvement. 

CRITERIA 

General Criteria Applicable to All Purposes 

Plant species, seedbed preparation, seeding 

rates, seeding dates, seeding depths, fertility 

requirements, and planting methods will be 

consistent with approved local criteria and site 

conditions. 

The species selected will be compatible with 

other components of the cropping system. 

Cover crops will be terminated by harvest, frost, 

mowing, tillage, crimping, and/or herbicides in 

preparation for the following crop. 

Herbicides used with cover crops will be 

compatible with the following crop. 

Avoid using plants that are on the state’s noxious 

weed or invasive species lists. 

Cover crop residue will not be burned. 

Additional Criteria to Reduce Erosion from 

Wind and Water 

Cover crop establishment, in conjunction with 

other practices, will be timed so that the soil will 

be adequately protected during the critical 

erosion period(s). 

Plants selected for cover crops will have the 

physical characteristics necessary to provide 

adequate protection. 

The amount of surface and/or canopy cover 

needed from the cover crop shall be determined 

using current erosion prediction technology. 

Additional Criteria to Increase Soil Organic 

Matter Content 

Cover crop species will be selected on the basis 

of producing high volumes of organic material 
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and or root mass to maintain or improve soil 

organic matter. 

The NRCS Soil Conditioning Index (SCI) 

procedure will be used to determine the amount 

of biomass required to have a positive trend in 

the soil organic matter subfactor. 

The cover crop will be terminated as late as 

feasible to maximize plant biomass production, 

considering the time needed to prepare the field 

for planting the next crop and soil moisture 

depletion. 

Additional Criteria to Capture and Recycle 

Excess Nutrients in the Soil Profile 

Cover crops will be established and actively 

growing before the expected period(s) of nutrient 

leaching. 

Cover crop species will be selected for their 

ability to take up large amounts of nutrients from 

the rooting profile of the soil. 

When used to redistribute nutrients from deeper 

in the profile up to the surface layer, the cover 

crop will be killed in relation to the planting date 

of the following crop. If the objective is to best 

synchronize the use of cover crop as a green 

manure to cycle nutrients, factors such as the 

carbon/nitrogen ratios may be considered to kill 

early and have a faster mineralization of 

nutrients to match release of nutrient with uptake 

by following cash crop. A late kill may be used if 

the objectives are to use as a biocontrol and 

maximize the addition of organic matter. The 

right moment to kill the cover crop will depend on 

the specific rotation, weather and objectives. 

Additional Criteria to Promote Biological 

Nitrogen Fixation 

Only legumes or legume-grass mixtures will be 

established as cover crops. 

The specific Rhizobium bacteria for the selected 

legume will either be present in the soil or the 

seed will be inoculated at the time of planting. 

Additional Criteria to Increase Biodiversity 

Cover crop species shall be selected that have 

different maturity dates, attract beneficial insects, 

increase soil biological diversity, serve as a trap

crop for damaging insects, and/or provide food 

and cover for wildlife habitat management. 

Additional Criteria for Weed Suppression 

Species for the cover crop will be selected for 

their chemical or physical characteristics to 

suppress or compete with weeds. 

Cover crops residues will be left on the soil 

surface to maximize allelopathic (chemical) and 

mulching (physical) effects. 

For long-term weed suppression, reseeding 

annuals and/or biennial species can be used. 

Additional Criteria to Provide Supplemental 

Forage 

Species selected will have desired forage traits, 

be palatable to livestock, and not interfere with 

the production of the subsequent crop. 

Forage provided by the cover crop may be hayed 

or grazed as long as sufficient biomass is left for

resource protection. 

Additional Criteria for Soil Moisture 

Management 

Terminate growth of the cover crop sufficiently 

early to conserve soil moisture for the 

subsequent crop. Cover crops established for 

moisture conservation shall be left on the soil 

surface. 

In areas of potential excess soil moisture, allow 

the cover crop to grow as long as possible to 

maximize soil moisture removal. 

Additional Criteria to Reduce Particulate 

Emissions into the Atmosphere 

Manage cover crops and their residues so that at 

least 80% ground cover is maintained during 

planting operations for the following crop. 

Additional Criteria to Minimize and Reduce 

Soil Compaction

Select and manage cover crop species that will 

produce deep roots and large amounts of 

surface or root biomass to increase soil organic 
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matter, improve soil structure and increase soil 

moisture through better infiltration. 

CONSIDERATIONS 

Plant cover crop in a timely matter to establish a 

good stand. 

Maintain an actively growing cover crop as late 

as feasible to maximize plant growth, allowing 

time to prepare the field for the next crop and 

moisture depletion. 

Use deep-rooted species to maximize nutrient 

recovery. 

Use grasses to utilize more soil nitrogen, and 

legumes utilize both nitrogen and phosphorus. 

Avoid cover crop species that harbor or 

carryover potentially damaging diseases or 

insects. 

For most purposes for which cover crops are 

established, the combined canopy and surface 

cover is at nearly 90 percent or greater, and the 

above ground (dry weight) biomass production is 

at least 4,000 lbs/acre. 

Cover crops may be used to improve site 

conditions for establishment of perennial 

species. 

Use plant species that enhance bio-fuels 

opportunities. 

Use plant species that enhance forage 

opportunities for pollinators. 

PLANS AND SPECIFICATIONS 

Plans and specifications will be prepared for the 

practice site. Plans for the establishment of 

cover crops shall include: 

• Species or species of plants to be 

established. 

• Seeding rates. 

• Recommended seeding dates. 

• Establishment procedure. 

• Planned rates and timing of nutrient 

application. 

• Planned dates for destroying cover crop. 

• Other information pertinent to establishing 

and managing the cover crop. 

Plans and specifications for the establishment 

and management of cover crops may be 

recorded in narrative form, on job sheets, or on 

other forms. 

OPERATION AND MAINTENANCE 

Control growth of the cover crop to reduce 

competition from volunteer plants and shading. 

Control weeds in cover crops by mowing or by 

using other pest management techniques. 

Control soil moisture depletion by selecting water 

efficient plant species and terminating the cover 

crop before excessive transpiration. 

REFERENCES 

Bowman, G., C. Cramer, and C. Shirley. A. Clark 

(ed.). 1998. Managing cover crops profitably. 

2nd ed. Sustainable Agriculture Network 

Handbook Series; bk 3. National Agriculture 

Library. Beltsville, MD. 

Hargrove, W.L., ed. Cover crops for clean water. 

SWCS, 1991. 

Magdoff, F. and H. van Es. Cover Crops. 2000. 

p. 87-96 In Building soils for better crops. 2nd 

ed. Sustainable Agriculture Network Handbook 

Series; bk 4. National Agriculture Library. 

Beltsville, MD. 

Reeves, D.W. 1994. Cover crops and erosion. p. 

125-172 In J.L. Hatfield and B.A. Stewart (eds.) 

Crops Residue Management. CRC Press, Boca 

Raton, FL.
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Conservation practice standards are reviewed periodically, and updated if needed. To obtain 

the current version of this standard, contact the Natural Resources Conservation Service 

NATURAL RESOURCES CONSERVATION SERVICE 

CONSERVATION PRACTICE STANDARD 

WASTE TREATMENT LAGOON 

(No.) 

CODE 359 

DEFINITION 

A waste treatment impoundment made by 

constructing an embankment and/or excavating 

a pit or dugout. 

PURPOSE 

To biologically treat waste, such as manure 

and wastewater, and thereby reduce pollution 

potential by serving as a treatment component 

of a waste management system. 

CONDITIONS WHERE PRACTICE APPLIES 

• Where the lagoon is a component of a 

planned agricultural waste management 

system. 

• Where treatment is needed for organic 

wastes generated by agricultural 

production or processing. 

• On any site where the lagoon can be 

constructed, operated and maintained 

without polluting air or water resources. 

• To lagoons utilizing embankments with an 

effective height of 35 feet or less where 

damage resulting from failure would be 

limited to damage of farm buildings, 

agricultural land, or township and country 

roads. 

CRITERIA 

General Criteria for All Lagoons

Laws and Regulations. All Federal, state, 

and local laws, rules, and regulations governing 

the construction and use of waste treatment 

lagoons must be followed. 

Location. To minimize the potential for 

contamination of streams, lagoons should be 

located outside of floodplains. However, if site 

restrictions require location within a floodplain, 

they shall be protected from inundation or 

damage from a 25-year flood event, or larger if 

required by laws, rules, and regulations. 

Lagoons shall be located so the potential 

impacts from breach of embankment, 

accidental release, and liner failure are 

minimized; and separation distances are such 

that prevailing winds and landscape elements 

such as building arrangement, landforms, and 

vegetation minimize odors and protect 

aesthetic values. 

Lagoons should be located so they have as 

little drainage area as possible. If a lagoon has 

a drainage area, the volume of normal runoff 

during the treatment period and 25-year, 24-

hour storm event runoff shall be included in the 

required volume of the lagoon. 

Soils and Foundation. The lagoon shall be 

located in soils with an acceptable permeability 

that meets all applicable regulations, or the 

lagoon shall be lined. Information and 

guidance on controlling seepage from waste 

impoundments can be found in the Agricultural 

Waste Management Field Handbook 

(AWMFH), Appendix 10D. 

The lagoon shall have a bottom elevation that 

is a minimum of 2 feet above the seasonal high 

water table unless special design features are 

incorporated that address buoyant forces, 

lagoon seepage rates, and non-encroachment 
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of the water table by contaminants. The water 

table may be lowered by use of perimeter 

drains to meet this requirement. 

Flexible Membranes. Flexible membrane 

liners shall meet or exceed the requirements of 

flexible membrane linings specified in Pond 

Sealing or Lining, Flexible Membrane (code 

521A). 

Required Volume. The lagoon shall have the 

capability of storing the following volumes: 

• Volume of accumulated sludge for the 

period between sludge removal events; 

• Minimum treatment volume (anaerobic 

lagoons only); 

• Volume of manure, wastewater, and other 

wastes accumulated during the treatment 

period; 

• Depth of normal precipitation less 

evaporation on the surface area (at the 

required volume level) of the lagoon during 

the treatment period; 

• Depth of the 25-year, 24-hour storm 

precipitation on the surface area (at the 

required volume level) of the lagoon. 

Treatment Period. The treatment period is the 

detention time between drawdown events. It 

shall be the greater of either 60 days; or the 

time required to provide the storage that allows 

environmentally safe utilization of waste 

considering the climate, crops, soil, and 

equipment requirements; or as required by 

local, state, and Federal regulations. 

Waste Loading. Daily waste loading shall be 

based on the maximum daily loading 

considering all waste sources that will be 

treated by the lagoon. Reliable local 

information or laboratory test data should be 

used if available. If local information is not 

available Chapter 4 of the AWMFH may be 

used for estimating waste loading. 

Embankments. The minimum elevation of the 

top of the settled embankment shall be 1 foot 

above the lagoon’s required volume. This 

height shall be increased by the amount 

needed to ensure that the top elevation will be 

maintained after settlement. This increase 

shall be not less than 5 percent. The minimum 

top widths are shown in Table 1. The 

combined side slopes of the settled 

embankment shall not be less than 5 horizontal 

to 1 vertical, and neither slope shall be steeper 

than 2 horizontal to 1 vertical unless provisions 

are made to provide stability. 

Table 1 – Minimum Top Widths 

Total embankment Top Width, 

 Height, ft. ft. 

 15 or less 8 

 15 – 20 10 

 20 – 25 12 

 25 – 30 14 

 30 – 35 15 

Excavations. Unless supported by a soil 

investigation, excavated side slopes shall be no 

steeper than 2 horizontal to 1 vertical. 

Inlet. Inlets shall be of any permanent type 

designed to resist corrosion, plugging, freeze 

damage, and ultraviolet ray deterioration, while 

incorporating erosion protection as necessary. 

Inlets shall be provided with a water-sealed trap 

and vent, or similar device if there is a 

potential, based on design configuration, for 

gases to enter buildings or other confined 

spaces. 

Outlet. Outlets from the required volume shall 

be designed to resist corrosion and plugging. 

No outlet shall automatically discharge from the 

required volume of the lagoon. 

Facility for Drawdown. Measures that 

facilitate safe drawdown of the liquid level in the

lagoon shall be provided. Access areas and 

ramps used to withdraw waste shall have 

slopes that facilitate a safe operating 

environment. Docks, wells, pumping platforms, 

retaining walls, etc. shall permit drawdown 

without causing erosion or damage to liners. 

Sludge Removal. Provision shall be made for 

periodic removal of accumulated sludge to 

preserve the treatment capacity of the lagoon. 

Erosion Protection. Embankments and 

disturbed areas surrounding the lagoon shall 

be treated to control erosion. This includes the 

inside slopes of the lagoon as needed to 

protect the integrity of the liner. 
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Conservation practice standards are reviewed periodically, and updated if needed. To obtain 

the current version of this standard, contact the Natural Resources Conservation Service 

Safety. Design shall include appropriate safety 

features to minimize the hazards of the lagoon. 

The lagoon shall be fenced around the 

perimeter and warning signs posted to prevent 

children and others from using it for other than 

its intended purpose. 

Additional Criteria for Anaerobic Lagoons

Loading Rate. Anaerobic lagoons shall be 

designed to have a minimum treatment volume 

based on Volatile Solids (VS) loading per unit 

of volume. The maximum loading rate shall be 

as indicated in AWMFH Figure 10-22 or 

according to state regulatory requirements, 

whichever is more stringent. 

Operating Levels. The maximum operating 

level shall be the lagoon level that provides the 

required volume less the 25-year, 24-hour 

storm event precipitation on the surface of the 

lagoon. The maximum drawdown level shall be 

the lagoon level that provides volume for the 

required minimum treatment volume plus the 

volume of accumulated sludge between sludge 

removal events. Permanent markers shall be 

installed at these elevations. The proper 

operating range of the lagoon is above the 

maximum drawdown level and below the 

maximum operating level. These markers shall 

be referenced and described in the O&M plan. 

Depth Requirements. The minimum depth at 

maximum drawdown shall be 6 feet. If 

subsurface conditions prevent practicable 

construction to accommodate the minimum 

depth at maximum drawdown, a lesser depth 

may be used, if the volume requirements are 

met. 

Additional Criteria for Naturally Aerobic 

Lagoons

Loading Rate. Naturally aerobic lagoons shall 

be designed to have a minimum treatment 

surface area as determined on the basis of 

daily BOD5 loading per unit of lagoon surface. 

The required minimum treatment surface area 

shall be the surface area at maximum 

drawdown. The maximum loading rate shall be 

as indicated by AWMFH Figure 10-25 or 

according to state regulatory requirements, 

whichever is more stringent. 

Operating Levels. The maximum operating 

level shall be the lagoon level that provides the 

required volume less the 25-year, 24-hour 

storm event on the lagoon surface. The 

maximum drawdown level shall be the lagoon 

level that provides volume for the volume of 

manure, wastewater, and clean water 

accumulated during the treatment period plus 

the volume of accumulated sludge between 

sludge removal events. Permanent markers 

shall be installed at these elevations. The 

proper operating range of the lagoon is above 

the maximum drawdown level and below the 

maximum operating level. These markers shall 

be referenced and described in the O&M plan. 

Depth Requirements. The minimum depth at 

maximum drawdown shall be 2 feet. The 

maximum liquid level shall be 5 feet. 

Additional Criteria for Mechanically Aerated 

Lagoons

Loading Rate. Mechanically aerated waste 

treatment lagoons’ treatment function shall be 

designed on the basis of daily BOD5 loading 

and aeration equipment manufacturer’s 

performance data for oxygen transfer and 

mixing. Aeration equipment shall provide a 

minimum of 1 pound of oxygen for each pound 

of daily BOD5 loading. 

Operating Levels. The maximum operating 

level shall be the lagoon level that provides the 

required lagoon volume less the 25-year, 24-

hour storm event precipitation and shall not 

exceed the site and aeration equipment 

limitations. A permanent marker or recorder 

shall be installed at this elevation. The proper 

operating range of the lagoon is below this 

elevation and above the minimum treatment 

elevation established by the manufacturer of 

the aeration equipment. This marker shall be 

referenced and described in the O&M plan. 

CONSIDERATIONS 

General

Lagoons should be located as close to the 

source of waste as possible. 
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the current version of this standard, contact the Natural Resources Conservation Service 

Solid/liquid separation treatment should be 

considered between the waste source and the 

lagoon to reduce loading. 

The configuration of the lagoon should be 

based on the method of sludge removal and 

method of sealing. 

Due consideration should be given to 

economics, the overall waste management 

system plan, and safety and health factors. 

Considerations for Minimizing the Potential 

for and Impacts of Sudden Breach of 

Embankment or Accidental Release from 

the Required Volume

Features, safeguards, and/or management 

measures to minimize the risk of embankment 

failure or accidental release, or to minimize or 

mitigate impact of this type of failure should be 

considered when any of the categories listed in 

Table 2 might be significantly affected. 

The following should be considered either 

singly or in combination to minimize the 

potential of or the consequences of sudden 

breach of embankments when one or more of 

the potential impact categories listed in Table 2 

may be significantly affected: 

• An auxiliary (emergency) spillway 

• Additional freeboard 

• Storage volume for the wet year rather than 

normal year precipitation 

• Reinforced embankment -- such as, 

additional top width, flattened and/or 

armored downstream side slopes 

• Secondary containment 

• Water level indicators or recorders 

The following should be considered to minimize 

the potential for accidental release from the 

required volume through gravity outlets when 

one or more of the potential impact categories 

listed in Table 2 may be significantly affected: 

• Outlet gate locks or locked gate housing 

• Secondary containment 

• Alarm system 

• Another means of emptying the required 

volume 

Considerations for Minimizing the Potential 

of Lagoon Liner Seepage

Consideration should be given to providing an 

additional measure of safety from lagoon 

seepage when any of the potential impact 

categories listed in Table 3 may be affected. 

Should any of the potential impact categories 

listed in Table 3 be affected, consideration 

should be given to the following: 

• A clay liner designed in accordance with 

procedures of AWMFH, Appendix 10D with 

a thickness and coefficient of permeability 

so that specific discharge is less than 1 x 

10-6 cm/sec. 

• A flexible membrane liner 

• A geosynthetic clay liner (GCL) flexible 

membrane liner 

Table 2- Potential Impact Categories 

from Breach of Embankment or 

Accidental Release 

1. Surface water bodies -- perennial 

streams, lakes, wetlands, and estuaries 

2. Critical habitat for threatened and 

endangered species 

3. Riparian areas 

4. Farmstead, or other areas of habitation 

5. Off-farm property 

6. Historical and/or archaeological sites or 

structures that meet the eligibility criteria 

for listing in the National Register of 

Historical Places 

Table 3 - Potential Impact Categories for 

Liner Seepage 

1. Any underlying aquifer is at a shallow depth 

and not confined 

2. The vadose zone is rock 

3. The aquifer is a domestic water supply or 

ecologically vital water supply 

4. The site is located in an area of carbonate 

rock (limestone or dolomite) 
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Conservation practice standards are reviewed periodically, and updated if needed. To obtain 

the current version of this standard, contact the Natural Resources Conservation Service 

• A concrete liner designed in accordance 

with slabs on grade criteria, Waste Storage 

Facility (313), for fabricated structures 

requiring water tightness. 

Considerations for Improving Air Quality 

To reduce emissions of greenhouse gases, 

ammonia, volatile organic compounds, and 

odor: 

• Reduce the recommended loading rate for 

anaerobic lagoons to one-half the values 

given in AWMFH Figure 10-22. 

• Use additional practices such as Anaerobic 

Digester – Ambient Temperature (365), 

Anaerobic Digester – Controlled 

Temperature (366), Waste Facility Cover 

(367) and Composting Facilities (code 317) 

in the waste management system. 

• Liquid/solid separation prior to discharge to 

lagoon will reduce volatile solids (VS) 

loading resulting in reduced gaseous 

emissions and odors. Composting of 

solids will further reduce emissions. 

• Design lagoons to be naturally aerobic or to 

allow mechanical aeration. 

Adjusting pH below 7 may reduce ammonia 

emissions from the lagoon but may increase 

odor when waste is surface applied (See 

Waste Utilization, code 633). 

PLANS AND SPECIFICATIONS 

Plans and specifications shall be prepared in 

accordance with the criteria of this standard 

and shall describe the requirements for 

applying the practice to achieve its intended 

use. 

OPERATION AND MAINTENANCE 

An operation and maintenance plan shall be 

developed that is consistent with the purposes 

of the practice, its intended life, safety 

requirements, and the criteria for design. The 

plan shall contain the operational requirements 

for drawdown and the role of permanent 

markers. This shall include the requirement 

that waste be removed from the lagoon and 

utilized at locations, times, rates, and volume in 

accordance with the overall waste 

management system plan. In addition, the plan 

shall include a strategy for removal and 

disposition of waste with least environmental 

damage during the normal treatment period to 

the extent necessary to insure the lagoon’s 

safe operation. This strategy shall also include 

the removal of unusual storm events. 

Development of an emergency action plan 

should be considered for lagoons where there 

is a potential for significant impact from breach 

or accidental release. The plan shall include 

site-specific provisions for emergency actions 

that will minimize these impacts. 
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Conservation practice standards are reviewed periodically, and updated if needed. To obtain 

the current version of this standard, contact the Natural Resources Conservation Service 

NATURAL RESOURCES CONSERVATION SERVICE 

CONSERVATION PRACTICE STANDARD 

DIVERSION 

(Ft.) 

CODE 362 

DEFINITION 

A channel constructed across the slope generally 

with a supporting ridge on the lower side. 

PURPOSE 

This practice may be applied as part of a resource 

management system to support one or more of the 

following purposes. 

• Break up concentrations of water on long 

slopes, on undulating land surfaces, and on 

land that is generally considered too flat or 

irregular for terracing. 

• Divert water away from farmsteads, 

agricultural waste systems, and other 

improvements. 

• Collect or direct water for water-spreading or 

water-harvesting systems. 

• Increase or decrease the drainage area above 

ponds. 

• Protect terrace systems by diverting water 

from the top terrace where topography, land 

use, or land ownership prevents terracing the 

land above. 

• Intercept surface and shallow subsurface flow. 

• Reduce runoff damages from upland runoff. 

• Reduce erosion and runoff on urban or 

developing areas and at construction or mining 

sites. 

• Divert water away from active gullies or 

critically eroding areas. 

• Supplement water management on 

conservation cropping or stripcropping 

systems. 

CONDITIONS WHERE PRACTICE APPLIES 

This applies to all cropland and other land 

uses where surface runoff water control and or 

management is needed. It also applies where 

soils and topography are such that the 

diversion can be constructed and a suitable 

outlet is available or can be provided. 

CRITERIA

Capacity. Diversions as temporary measures, 

with an expected life span of less than 2 years, 

shall have a minimum capacity for the peak 

discharge from the 2-year frequency, 24-hour 

duration storm. 

Diversions that protect agricultural land shall 

have a minimum capacity for the peak 

discharge from a 10-year frequency, 24 -hour 

duration storm. 

Diversions designed to protect areas such as 

urban areas, buildings, roads, and animal 

waste management systems shall have a 

minimum capacity for the peak discharge from 

a storm frequency consistent with the hazard 

involved but not less than a 25-year frequency, 

24-hour duration storm. Freeboard shall be 

not less than 0.3 ft. 

Design depth is the channel storm flow depth 

plus freeboard, where required. 

Cross section. The channel may be 

parabolic, V-shaped, or trapezoidal. The 

diversion shall be designed to have stable side 

slopes. 
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The ridge shall have a minimum top width of 4 feet 

at the design depth. The ridge height shall include 

an adequate settlement factor. 

The ridge top width may be 3 feet at the design 

depth for diversions with less than 10 acres 

drainage area above cropland, pastureland, or 

woodland. 

The top of the constructed ridge at any point shall

not be lower than the design depth plus the 

specified overfill for settlement. 

The design depth at culvert crossings shall be the 

culvert headwater depth for the design storm plus 

freeboard. 

Grade and velocity. Channel grades may be 

uniform or variable. Channel velocity shall not 

exceed that considered non-erosive for the soil 

and planned vegetation or lining. 

Maximum channel velocities for permanently 

vegetated channels shall not exceed those 

recommended in the NRCS Engineering Field 

Handbook (EFH) Part 650, Chapter 7, or 

Agricultural Research Service (ARS) Agricultural 

Handbook 667, Stability Design of Grass-Lined 

Open Channels (Sept. 1987). 

When the capacity is determined by the formula Q 

= A V and the V is calculated by using Manning's 

equation, the highest expected value of "n" shall 

be used. 

Location. The outlet conditions, topography, land 

use, cultural operations, cultural resources, and 

soil type shall determine the location of the 

diversion. 

Protection against sedimentation. Diversions 

normally should not be used below high sediment 

producing areas. When they are, a practice or 

combination of practices needed to prevent 

damaging accumulations of sediment in the 

channel shall be installed. This may include 

practices such as land treatment erosion control 

practices, cultural or tillage practices, vegetated

filter strip, or structural measures. Install practices 

in conjunction with or before the diversion 

construction. 

If movement of sediment into the channel is a 

problem, the design shall include extra capacity for 

sediment or periodic removal as outlined in the 

operation and maintenance plan. 

Outlets. Each diversion must have a safe and 

stable outlet with adequate capacity. The 

outlet may be a grassed waterway, a lined 

waterway, a vegetated or paved area, a grade 

stabilization structure, an underground outlet, a 

stable watercourse, a sediment basin, or a 

combination of these practices. The outlet 

must convey runoff to a point where outflow 

will not cause damage. Vegetative outlets 

shall be installed and established before 

diversion construction to insure establishment 

of vegetative cover in the outlet channel. 

The release rate of an under ground outlet, 

when combined with storage, shall be such 

that the design storm runoff will not overtop the 

diversion ridge. 

The design depth of the water surface in the 

diversion shall not be lower than the design 

elevation of the water surface in the outlet at 

their junction when both are operating at 

design flow. 

Vegetation. Disturbed areas that are not to 

be cultivated shall be seeded as soon as 

practicable after construction. 

Lining. If the soils or climatic conditions 

preclude the use of vegetation for erosion 

protection, non-vegetative linings such as 

gravel, rock riprap, cellular block, or other 

approved manufactured lining systems may be 

used. 

CONSIDERATIONS 

A diversion in a cultivated field should be 

aligned and spaced from other structures or 

practices to permit use of modern farming 

equipment. The side slope lengths should 

sized to fit equipment widths when cropped. 

At non-cropland sites, consider planting native 

vegetation in areas disturbed due to 

construction. 

Maximize wetland functions and values with 

the diversion design. Minimize adverse effects 

to existing functions and values. Diversion of 

upland water to prevent entry into a wetland 
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the current version of this standard, contact the Natural Resources Conservation Service 

may convert a wetland by changing the hydrology. 

Any construction activities should minimize 

disturbance to wildlife habitat. Opportunities 

should be explored to restore and improve wildlife 

habitat, including habitat for threatened, 

endangered, and other species of concern. 

On landforms where archeological sites are likely 

to occur, use techniques to maximize identification

of such sites prior to planning, design, and 

construction. 

PLANS AND SPECIFICATIONS 

Plans and specification for installing diversions 

shall be in keeping with this standard and shall 

describe the requirements for applying the practice

to achieve its intended purpose. 

OPERATION AND MAINTENANCE 

An operation and maintenance plan shall be 

prepared for use by the client. The plan shall 

include specific instructions for maintaining 

diversion capacity, storage, ridge height, and 

outlets. 

The minimum requirements to be addressed in the 

operation and maintenance plan are: 

1. Provide periodic inspections, especially 

immediately following significant storms. 

2. Promptly repair or replace damaged 

components of the diversion as necessary. 

3. Maintain diversion capacity, ridge height, 

and outlet elevations especially if high 

sediment yielding areas are in the 

drainage area above the diversion. 

Establish necessary clean-out 

requirements. 

4. Each inlet for underground outlets must be 

kept clean and sediment buildup 

redistributed so that the inlet is at the 

lowest point. Inlets damaged by farm 

machinery must be replaced or repaired 

immediately. 

5. Redistribute sediment as necessary to 

maintain the capacity of the diversion. 

6. Vegetation shall be maintained and trees 

and brush controlled by hand, chemical 

and/or mechanical means. 

7. Keep machinery away from steep sloped 

ridges. Keep equipment operators 

informed of all potential hazards. 
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Conservation practice standards are reviewed periodically, and updated if needed. To obtain 

the current version of this standard, contact the Natural Resources Conservation Service 

NATURAL RESOURCES CONSERVATION SERVICE 

CONSERVATION PRACTICE STANDARD 

ROOF RUNOFF STRUCTURE 

(No.) 

CODE 558 

DEFINITION 

Structures that collect, control, and transport 

precipitation from roofs. 

PURPOSE 

To improve water quality, reduce soil erosion, 

increase infiltration, protect structures, and/or 

increase water quantity. 

CONDITIONS WHERE PRACTICE APPLIES 

Where roof runoff from precipitation needs to be: 

• diverted away from structures or contaminated 

areas; 

• collected, controlled, and transported to a 

stable outlet; or 

• collected and used for other purposes such as 

irrigation or animal watering facility. 

CRITERIA 

General Criteria Applicable to All Purposes 

The minimum design capacity for roof runoff 

structures shall be a 10-year storm frequency, 5-

minute rainfall precipitation event, except where 

excluding roof runoff from manure management 

facilities. In that case, a 25-year frequency, 5-

minute precipitation event shall be used to design 

roof runoff structures (Refer to Agricultural Waste

Management Field Handbook, NEH Part 651

Chapter 10 Appendix 10B). When gutters are 

used, the capacity of the downspout(s) must equal 

or exceed the gutter flow rate. 

Runoff may empty into surface or underground 

outlets, or onto the ground surface. Surface and 

underground outlets shall be sized to ensure 

adequate design capacity and shall provide for 

clean-out as appropriate. When runoff from roofs 

empties onto the ground surface, a stable outlet 

shall be provided. When runoff is conveyed 

through a gutter and downspout system, an elbow 

and energy dissipation device shall be placed at 

the end of the downspout to provide a stable outlet

and direct water away from the building. 

Surface or ground outlets such as rock pads, rock 

filled trenches with subsurface drains, concrete 

and other erosion-resistant pads, or preformed 

channels may be used, particularly where snow 

and ice are a significant load component on roofs. 

In regions where snow and ice will accumulate on 

roofs, guards and sufficient supports to withstand 

the anticipated design load shall be included. 

Roof runoff structures shall be made of durable 

materials with a minimum design life of ten years. 

Roof gutters and downspouts may be made of 

aluminum, galvanized steel, wood, or plastic. 

Aluminum gutters and downspouts shall have a 

minimum nominal thickness of 0.027 inches and 

0.020 inches, respectively. Galvanized steel 

gutters and downspouts shall be a minimum 28 

gauge. Wood shall be clear and free of knots. 

Wood may be redwood, cedar, cypress, or other 

species that has the desired longevity. Plastics 

shall contain ultraviolet stabilizers. Dissimilar 

metals shall not be in contact with each other. 

Rock-filled trenches and pads shall consist of 

poorly graded rock (all rock fragments 

approximately the same size) and be free of 

appreciable amounts of sand and/or soil particles. 
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Conservation practice standards are reviewed periodically, and updated if needed. To obtain 

the current version of this standard, contact the Natural Resources Conservation Service 

Crushed limestone shall not be used for backfill 

material unless it has been washed. Subsurface 

drains or outlets shall meet the material 

requirements of the applicable NRCS 

conservation practice standard. 

Concrete appurtenances used shall meet the 

requirements of NRCS NEH Part 642, Chapter 2, 

Construction Specification 32 Structure Concrete. 

Roof runoff structures shall be protected from 

damage by livestock and equipment. 

Additional Criteria to Increase Infiltration 

Runoff shall be routed onto pervious landscaped 

areas (e.g., lawns, mass planting areas, infiltration 

trenches, and natural areas) to increase infiltration 

of runoff. These areas shall be capable of 

infiltrating the runoff in such a way that replenishes 

soil moisture without adversely affecting the 

desired plant species. 

Additional Criteria to Protect Structures 

Runoff shall be directed away from structure 

foundations to avoid wetness and hydraulic 

loading on the foundation. 

On expansive soils or bedrock, downspout 

extensions shall be used to discharge runoff a 

minimum of five (5) feet from the structure. 

The discharge area for runoff must slope away 

from the protected structure. 

Additional Criteria to Increase Water Quantity 

Storage structures for non-potable purposes such 

as irrigation water shall be designed in accordance

with NRCS conservation practice standards, as 

appropriate. 

Potable water storage structures shall be 

constructed of materials and in a manner that will 

not increase the contamination of the stored 

water. Roof runoff collected and stored for 

potable uses must be treated prior to consumption 

and shall be tested periodically to assure that 

adequate quality is maintained for human 

consumption. 

CONSIDERATIONS 

Avoid discharging outlets near wells and 

sinkholes. 

Some designs may provide secondary benefits, 

e.g. rock pads may also reduce rodent problems 

around livestock and poultry barns. 

PLANS AND SPECIFICATIONS 

The plans and specifications shall show the 

location, spacing, size, and grade of all gutters 

and downspouts and type and quality of material 

to be used. Plans and specifications for other 

practices essential to the proper functioning of the 

roof runoff structure, such as underground outlet, 

shall be included. 

OPERATION AND MAINTENANCE 

An operation and maintenance plan shall be 

developed that is consistent with the purposes of 

the practice, its intended life, safety requirements, 

and the criteria for the design. The plan shall 

contain, but not be limited to, the following 

provisions: 

• Keep roof runoff structures clean and free of 

obstructions that reduce flow. 

• Make regular inspections and perform repair 

maintenance as needed to ensure proper 

functioning of the roof runoff structures. 

REFERENCES 

USDA-NRCS. 1999. National Engineering 

Handbook, Part 651, Agricultural Waste 

Management Field Handbook. 
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Conservation practice standards are reviewed periodically, and updated if needed. To obtain 

the current version of this standard, contact the Natural Resources Conservation Service 

NATURAL RESOURCES CONSERVATION SERVICE 

CONSERVATION PRACTICE STANDARD 

NUTRIENT MANAGEMENT 

(Ac.) 

CODE 590 

DEFINITION 

Managing the amount, source, placement, form 

and timing of the application of plant nutrients 

and soil amendments. 

PURPOSE 

• To budget and supply nutrients for plant 

production. 

• To properly utilize manure or organic byproducts as a plant nutrient source. 

• To minimize agricultural nonpoint source 

pollution of surface and ground water 

resources. 

• To protect air quality by reducing nitrogen 

emissions (ammonia and NOx compounds) 

and the formation of atmospheric 

particulates. 

• To maintain or improve the physical, 

chemical and biological condition of soil. 

CONDITIONS WHERE PRACTICE APPLIES 

This practice applies to all lands where plant 

nutrients and soil amendments are applied. 

CRITERIA 

General Criteria Applicable to All Purposes 

A nutrient budget for nitrogen, phosphorus, and 

potassium shall be developed that considers all 

potential sources of nutrients including, but not 

limited to animal manure and organic byproducts, waste water, commercial fertilizer, crop 

residues, legume credits, and irrigation water. 

Realistic yield goals shall be established based 

on soil productivity information, historical yield 

data, climatic conditions, level of management 

and/or local research on similar soil, cropping 

systems, and soil and manure/organic byproducts tests. 

For new crops or varieties, industry yield 

recommendations may be used until 

documented yield information is available. 

Plans for nutrient management shall specify the 

source, amount, timing and method of 

application of nutrients on each field to achieve 

realistic production goals, while minimizing 

movement of nutrients and other potential 

contaminants to surface and/or ground waters. 

Areas contained within established minimum 

application setbacks (e.g., sinkholes, wells, 

gullies, ditches, surface inlets or rapidly 

permeable soil areas) shall not receive direct 

application of nutrients. 

The amount of nutrients lost to erosion, runoff, 

irrigation and drainage, shall be addressed, as 

needed. 

Soil and Tissue Sampling and Laboratory 

Analyses (Testing). Nutrient planning shall be 

based on current soil and tissue (where used as 

a supplement) test results developed in 

accordance with Land Grant University 

guidance, or industry practice if recognized by 

the Land Grant University. Current soil tests are 

those that are no older than five years. 

Soil and tissue samples shall be collected and 

prepared according to the Land Grant University 

guidance or standard industry practice. Soil and 

tissue test analyses shall be performed by 
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the current version of this standard, contact the Natural Resources Conservation Service 

laboratories that are accepted in one or more of 

the following: 

• Laboratories successfully meeting the 

requirements and performance standards of 

the North American Proficiency Testing 

Program (NAPT) under the auspices of the 

Soil Science Society of America, or 

• State recognized program that considers 

laboratory performance and proficiency to 

assure accuracy of soil test results.

Soil and tissue testing shall include analyses for 

any nutrients for which specific information is 

needed to develop the nutrient plan. Request 

analyses pertinent to monitoring or amending the 

annual nutrient budget, e.g. pH, electrical 

conductivity (EC), soil organic matter, nitrogen, 

phosphorus and potassium. 

Nutrient Application Rates. Soil amendments 

shall be applied, as needed, to adjust soil pH to 

an adequate level for crop nutrient availability 

and utilization. 

Recommended nutrient application rates shall be 

based on Land Grant University 

recommendations (and/or industry practice when 

recognized by the university) that consider 

current soil test results, realistic yield goals and 

management capabilities. If the Land Grant 

University does not provide specific 

recommendations, application shall be based on 

realistic yield goals and associated plant nutrient

uptake rates. 

The planned rates of nutrient application, as 

documented in the nutrient budget, shall be 

determined based on the following guidance: 

• Nitrogen Application - Planned nitrogen 

application rates shall match the 

recommended rates as closely as possible, 

except when manure or organic by-products 

are a source of nutrients. When manure or 

organic by-products are a source of 

nutrients, see “Additional Criteria” below. 

• Phosphorus Application - Planned 

phosphorus application rates shall match the 

recommended rates as closely as possible, 

except when manure or organic by-products 

are sources of nutrients. When manure or 

organic by-products are a source of 

nutrients, see “Additional Criteria” below. 

• Potassium Application - Potassium shall not 

be applied in situations in which excess 

(greater than soil test potassium 

recommendation) causes unacceptable 

nutrient imbalances in crops or forages. 

When forage quality is an issue associated 

with excess potassium application, state 

standards shall be used to set forage quality 

guidelines. 

• Other Plant Nutrients - The planned rates of 

application of other nutrients shall be 

consistent with Land Grant University 

guidance or industry practice if recognized 

by the Land Grant University in the state. 

• Starter Fertilizers - When starter fertilizers 

are used, they shall be included in the 

overall nutrient budget, and applied in 

accordance with Land Grant University 

recommendations, or industry practice if 

recognized by the Land Grant University 

within the state. 

Nutrient Application Timing. Timing and 

method of nutrient application (particularly 

nitrogen) shall correspond as closely as possible 

with plant nutrient uptake characteristics, while 

considering cropping system limitations, weather 

and climatic conditions, risk assessment tools 

(e.g., leaching index, P index) and field 

accessibility. 

Nutrient Application Methods. Application 

methods to reduce the risk of nutrient transport 

to surface and ground water, or into the 

atmosphere shall be employed. 

To minimize nutrient losses: 

• Apply nutrient materials uniformly to 

application area(s). 

• Nutrients shall not be applied to frozen, 

snow-covered or saturated soil if the 

potential risk for runoff exists. 

• Nutrients shall be applied considering the 

plant growth habits, irrigation practices, and 

other conditions so as to maximize 

availability to the plant and minimize the risk 

of runoff, leaching, and volatilization losses. 
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Conservation practice standards are reviewed periodically, and updated if needed. To obtain 

the current version of this standard, contact the Natural Resources Conservation Service 

• Nutrient applications associated with 

irrigation systems shall be applied in a 

manner that prevents or minimizes resource 

impairment. 

Conservation Management Unit (CMU) Risk 

Assessment. In areas with identified or 

designated nutrient related water quality 

impairment, a CMU specific risk assessment of 

the potential for nutrient transport from the area 

shall be completed. 

States that utilize a threshold prescreening 

procedure to trigger CMU risk assessment shall 

follow approved procedures as recommended by 

the respective state or Land Grant University. 

Use an appropriate nutrient risk assessment tool 

for the nutrient in question (e.g., leaching index,

phosphorus index) or other state recognized 

assessment tool. 

Additional Criteria Applicable to Manure and 

Organic By-Products or Biosolids Applied as 

a Plant Nutrient Source 

When animal manures or organic by-products 

are applied, a risk assessment of the potential 

for nutrient transport from the CMU shall be 

completed to adjust the amount, placement, 

form and timing of application of nutrient 

sources, as recommended by the respective 

state or Land Grant University. 

Nutrient values of manure and organic byproducts (excluding sewage sludge or biosolids) 

shall be determined prior to land application. 

Samples will be taken and analyzed with each 

hauling/emptying cycle for a storage/treatment 

facility. Manure sampling frequency may vary 

based on the operation’s manure handling 

strategy and spreading schedule. If there is no 

prior sampling history, the manure shall be 

analyzed at least annually for a minimum of 

three consecutive years. A cumulative record 

shall be developed and maintained until a 

consistent (maintaining a certain nutrient 

concentration with minimal variation) level of 

nutrient values is realized. The average of 

results contained in the operation’s cumulative 

manure analyses history shall be used as a 

basis for nutrient allocation to fields. Samples 

shall be collected and prepared according to 

Land Grant University guidance or industry 

practice. 

In planning for new operations, acceptable “book 

values” recognized by the NRCS and/or the 

Land Grant University may be used if they 

accurately estimate nutrient output from the 

proposed operation (e.g., NRCS Agricultural 

Waste Management Field Handbook). 

Biosolids (sewage sludge) shall be applied in 

accordance with USEPA regulations. (40 CFR 

Parts 403 (Pretreatment) and 503 (Biosolids) 

and other state and/or local regulations 

regarding the use of biosolids as a nutrient 

source. 

Manure and Organic By-Product Nutrient 

Application Rates. Manure and organic byproduct nutrient application rates shall be based 

on nutrient analyses procedures recommended 

by the respective state or Land Grant University. 

As indicated above, “book values” may be used 

in planning for new operations. At a minimum, 

manure analyses shall identify nutrient and 

specific ion concentrations, percent moisture, 

and percent organic matter. Salt concentration 

shall be monitored so that manure applications 

do not cause plant damage or negatively impact 

soil quality. 

The application rate (in/hr) of liquid materials 

applied shall not exceed the soil intake/infiltration 

rate and shall be adjusted to minimize ponding 

and to avoid runoff. The total application shall 

not exceed the field capacity of the soil and shall

be adjusted, as needed, to minimize loss to 

subsurface tile drains. 

The planned rates of nitrogen and phosphorus 

application recorded in the plan shall be 

determined based on the following guidance: 

Nitrogen Application Rates 

o When manure or organic by-products 

are used, the nitrogen availability of the 

planned application rates shall match 

plant uptake characteristics as closely 

as possible, taking into consideration the 

timing of nutrient application(s) in order 

to minimize leaching and atmospheric 

losses. 
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the current version of this standard, contact the Natural Resources Conservation Service 

o Management activities and technologies 

shall be used that effectively utilize 

mineralized nitrogen and that minimize 

nitrogen losses through denitrification 

and ammonia volatilization. 

o Manure or organic by-products may be 

applied on legumes at rates equal to the 

estimated removal of nitrogen in 

harvested plant biomass. 

o When the nutrient management plan 

component is being implemented on a 

phosphorus basis, manure or organic 

by-products shall be applied at rates 

consistent with a phosphorus limited 

application rate. In such situations, an 

additional nitrogen application, from nonorganic sources, may be required to 

supply, but not exceed, the 

recommended amounts of nitrogen in 

any given year. 

Phosphorus Application Rates 

o When manure or organic by-products 

are used, the planned rates of 

phosphorus application shall be 

consistent with any one of the following 

options: 

◊ Phosphorus Index (PI) Rating. 

Nitrogen-based manure application 

on Low or Medium Risk Sites; 

phosphorus-based or no manure 

application on High and Very High 

Risk Sites.** 

◊ Soil Phosphorus Threshold Values. 

Nitrogen-based manure application 

on sites on which the soil test 

phosphorus levels are below the 

threshold values; Phosphorusbased or no manure application on 

sites on which soil phosphorus 

levels equal or exceed threshold 

values.** 

◊ Soil Test. Nitrogen-based manure 

application on sites for which the soil 

test recommendation calls for 

phosphorus application; 

phosphorus-based or no manure 

application on sites for which the soil 

test recommendation calls for no 

phosphorus application. ‡ 

** Acceptable phosphorusbased manure application rates 

shall be determined as a function of 

soil test recommendation or 

estimated phosphorus removal in 

harvested plant biomass. Guidance 

for developing these acceptable 

rates is found in the NRCS General 

Manual, Title 190, Part 402 

(Ecological Sciences, Nutrient 

Management, Policy), and the 

National Agronomy Manual, Section 

503 (to be developed). 

o The application of phosphorus applied 

as manure may be made at a rate equal 

to the recommended phosphorus 

application or estimated phosphorus 

removal in harvested plant biomass for 

the crop rotation or multiple years in the 

crop sequence. When such applications 

are made, the application rate shall: 

◊ Not exceed the recommended 

nitrogen application rate during the 

year of application, or 

◊ Not exceed the estimated nitrogen 

removal in harvested plant biomass 

during the year of application when 

there is no recommended nitrogen 

application. 

◊ Not be made on sites considered 

vulnerable to off-site phosphorus 

transport unless appropriate 

conservation practices, best 

management practices or 

management activities are used to 

reduce the vulnerability. 

Heavy Metal Monitoring. When sewage 

sludge (biosolids) is applied, the accumulation of 

potential pollutants (including arsenic, cadmium, 

copper, lead, mercury, selenium, and zinc) in the 

soil shall be monitored in accordance with the 

US Code, Reference 40 CFR, Parts 403 and 

503, and/or any applicable state and local laws 

or regulations.
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Conservation practice standards are reviewed periodically, and updated if needed. To obtain 

the current version of this standard, contact the Natural Resources Conservation Service 

Additional Criteria to Protect Air Quality by 

Reducing Nitrogen and/or Particulate 

Emissions to the Atmosphere 

In areas with an identified or designated nutrient 

management related air quality concern, any 

component(s) of nutrient management (i.e., 

amount, source, placement, form, timing of 

application) identified by risk assessment tools 

as a potential source of atmospheric pollutants 

shall be adjusted, as necessary, to minimize the 

loss(es). 

When tillage can be performed, surface 

applications of manure and fertilizer nitrogen 

formulations that are subject to volatilization on 

the soil surface (e.g., urea) shall be incorporated

into the soil within 24 hours after application. 

When manure or organic by-products are 

applied to grassland, hayland, pasture or 

minimum-till areas the rate, form and timing of 

application(s) shall be managed to minimize 

volatilization losses. 

When liquid forms of manure are applied with 

irrigation equipment, operators will select 

weather conditions during application that will 

minimize volatilization losses. 

Operators will handle and apply poultry litter or 

other dry types of animal manures when the 

potential for wind-driven loss is low and there is 

less potential for transport of particulates into the 

atmosphere. 

Weather and climatic conditions during manure 

or organic by-product application(s) shall be 

recorded and maintained in accordance with the 

operation and maintenance section of this 

standard. 

Additional Criteria to Improve the Physical, 

Chemical and Biological Condition of the Soil 

Nutrients shall be applied and managed in a 

manner that maintains or improves the physical, 

chemical and biological condition of the soil. 

Minimize the use of nutrient sources with high 

salt content unless provisions are made to leach 

salts below the crop root zone. 

To the extent practicable nutrients shall not be 

applied when the potential for soil compaction 

and rutting is high. 

CONSIDERATIONS 

The use of management activities and 

technologies listed in this section may improve 

both the production and environmental 

performance of nutrient management systems. 

The addition of these management activities, 

when applicable, increases the management 

intensity of the system and is recommended in a 

nutrient management system. 

Action should be taken to protect National 

Register listed and other eligible cultural 

resources. 

The nutrient budget should be reviewed annually 

to determine if any changes are needed for the 

next planned crop. 

For sites on which there are special 

environmental concerns, other sampling 

techniques may be appropriate. These include 

soil profile sampling for nitrogen, Pre-Sidedress 

Nitrogen Test (PSNT), Pre-Plant Soil Nitrate 

Test (PPSN) or soil surface sampling for 

phosphorus accumulation or pH changes. 

Additional practices to enhance the producer’s 

ability to manage manure effectively include 

modification of the animal’s diet to reduce the 

manure nutrient content, or utilizing manure 

amendments that stabilize or tie-up nutrients. 

Soil test information should be no older than one 

year when developing new plans, particularly if 

animal manures are to be used as a nutrient 

source. 

Excessive levels of some nutrients can cause 

induced deficiencies of other nutrients. 

If increases in soil phosphorus levels are 

expected, consider a more frequent (annual) soil 

testing interval. 

To manage the conversion of nitrogen in manure 

or fertilizer, use products or materials (e.g. 

nitrification inhibitors, urease inhibitors and slow 

or controlled release fertilizers) that more closely 

match nutrient release and availability for plant 
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the current version of this standard, contact the Natural Resources Conservation Service 

uptake. These materials may improve the 

nitrogen use efficiency (NUE) of the nutrient 

management system by reducing losses of 

nitrogen into water and/or air. 

Considerations to Minimize Agricultural 

Nonpoint Source Pollution of Surface and 

Ground Water. 

Erosion control and runoff reduction practices 

can improve soil nutrient and water storage, 

infiltration, aeration, tilth, diversity of soil 

organisms and protect or improve water and air 

quality (Consider installation of one or more 

NRCS FOTG, Section IV – Conservation 

Practice Standards). 

Cover crops can effectively utilize and/or recycle 

residual nitrogen. 

Apply nutrient materials uniformly to the 

application area. Application methods and 

timing that reduce the risk of nutrients being 

transported to ground and surface waters, or into 

the atmosphere include: 

• Split applications of nitrogen to provide 

nutrients at the times of maximum crop 

utilization, 

• Use stalk-test to minimize risk of over 

applying nitrogen in excess of crop needs. 

• Avoid winter nutrient application for spring 

seeded crops, 

• Band applications of phosphorus near the 

seed row, 

• Incorporate surface applied manures or 

organic by-products as soon as possible 

after application to minimize nutrient losses, 

• Delay field application of animal manures or 

organic by-products if precipitation capable 

of producing runoff and erosion is forecast 

within 24 hours of the time of the planned 

application. 

Considerations to Protect Air Quality by 

Reducing Nitrogen and/or Particulate 

Emissions to the Atmosphere. 

Odors associated with the land application of 

manures and organic by-products can be 

offensive to the occupants of nearby homes. 

Avoid applying these materials upwind of 

occupied structures when residents are likely to 

be home (evenings, weekends and holidays). 

When applying manure with irrigation equipment, 

modifying the equipment can reduce the 

potential for volatilization of nitrogen from the 

time the manure leaves the application 

equipment until it reaches the surface of the soil 

(e.g., reduced pressure, drop down tubes for 

center pivots). N volatilization from manure in a 

surface irrigation system will be reduced when 

applied under a crop canopy. 

When planning nutrient applications and tillage 

operations, encourage soil carbon buildup while 

discouraging greenhouse gas emissions (e.g., 

nitrous oxide N2O, carbon dioxide CO2). 

Nutrient applications associated with irrigation 

systems should be applied in accordance with 

the requirements of Irrigation Water 

Management (Code 449). 

CAFO operations seeking permits under USEPA 

regulations (40 CFR Parts 122 and 412) should 

consult with their respective state permitting 

authority for additional criteria. 

PLANS AND SPECIFICATIONS 

Plans and specifications for nutrient 

management shall be in keeping with this 

standard and shall describe the requirements for 

applying the practice to achieve its intended 

purpose(s), using nutrients to achieve production 

goals and to prevent or minimize resource 

impairment. 

Nutrient management plans shall include a 

statement that the plan was developed based on 

requirements of the current standard and any 

applicable Federal, state, or local regulations, 

policies, or programs, which may include the 

implementation of other practices and/or 

management activities. Changes in any of these 

requirements may necessitate a revision of the 

plan. 

The following components shall be included in 

the nutrient management plan: 

• aerial site photograph(s) or site map(s), and 

a soil survey map of the site, 
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the current version of this standard, contact the Natural Resources Conservation Service 

• location of designated sensitive areas or 

resources and the associated, nutrient 

management restriction, 

• current and/or planned plant production 

sequence or crop rotation, 

• results of soil, water, manure and/or organic 

by-product sample analyses, 

• results of plant tissue analyses, when used 

for nutrient management, 

• realistic yield goals for the crops, 

• complete nutrient budget for nitrogen, 

phosphorus, and potassium for the crop 

rotation or sequence, 

• listing and quantification of all nutrient 

sources, 

• CMU specific recommended nutrient 

application rates, timing, form, and method 

of application and incorporation, and 

• guidance for implementation, operation, 

maintenance, and recordkeeping. 

If increases in soil phosphorus levels are 

expected, the nutrient management plan shall 

document: 

• the soil phosphorus levels at which it may be 

desirable to convert to phosphorus based 

planning, 

• results of appropriate risk assessment tools 

to document the relationship between soil 

phosphorus levels and potential for 

phosphorus transport from the field, 

• the potential for soil phosphorus drawdown 

from the production and harvesting of crops, 

and 

• management activities or techniques used to 

reduce the potential for phosphorus loss. 

OPERATION AND MAINTENANCE 

The owner/client is responsible for safe 

operation and maintenance of this practice 

including all equipment. Operation and 

maintenance addresses the following: 

• periodic plan review to determine if 

adjustments or modifications to the plan are 

needed. As a minimum, plans will be 

reviewed and revised with each soil test 

cycle. 

• significant changes in animal numbers 

and/or feed management will necessitate 

additional manure sampling and analyses to 

establish a revised average nutrient content. 

• protection of fertilizer and organic by-product 

storage facilities from weather and 

accidental leakage or spillage. 

• calibration of application equipment to 

ensure uniform distribution of material at 

planned rates. 

• documentation of the actual rate at which 

nutrients were applied. When the actual 

rates used differ from the recommended and 

planned rates, records will indicate the 

reasons for the differences. 

• Maintaining records to document plan 

implementation. As applicable, records 

include: 

o Soil, plant tissue, water, manure, and 

organic by-product analyses resulting in 

recommendations for nutrient 

application, 

o quantities, analyses and sources of 

nutrients applied, 

o dates and method(s) of nutrient 

applications, 

o weather conditions and soil moisture at 

the time of application; lapsed time to 

manure incorporation, rainfall or 

irrigation event. 

o crops planted, planting and harvest 

dates, yields, and crop residues 

removed, 

o dates of plan review, name of reviewer, 

and recommended changes resulting 

from the review. 

Records should be maintained for five years; or 

for a period longer than five years if required by 

other Federal, state or local ordinances, or 

program or contract requirements. 
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Conservation practice standards are reviewed periodically, and updated if needed. To obtain 

the current version of this standard, contact the Natural Resources Conservation Service 

Workers should be protected from and avoid 

unnecessary contact with plant nutrient sources. 

Extra caution must be taken when handling 

ammoniacal nutrient sources, or when dealing 

with organic wastes stored in unventilated 

enclosures. 

Material generated from cleaning nutrient 

application equipment should be utilized in an 

environmentally safe manner. Excess material 

should be collected and stored or field applied in 

an appropriate manner. 

Nutrient containers should be recycled in 

compliance with state and local guidelines or 

regulations. 

REFERENCES 

Follett, R.F. 2001. Nitrogen Transformation and 

Transport Processes. pp. 17-44, In R.F. Follett 

and J. Hatfield. (eds.). 2001. Nitrogen in the 

Environment; Sources, Problems, and Solutions. 

Elsevier Science Publishers. The Netherlands. 

520 pp. 

Sims, J.T. (ed.) 2005. Phosphorus: Agriculture 

and the Environment. Agron. Monogr. 46. ASA, 

CSSA, and SSSA, Madison, WI. 

Stevenson, F.J. (ed.) 1982. Nitrogen in 

Agricultural Soils. Agron. Series 22. ASA, CSSA, 

and SSSA, Madison, WI. 
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the current version of this standard, contact the Natural Resources Conservation Service 

NATURAL RESOURCES CONSERVATION SERVICE 

CONSERVATION PRACTICE STANDARD 

WASTE UTILIZATION 

(Ac.) 

CODE 633 

DEFINITION 

Using agricultural wastes such as manure and 

wastewater or other organic residues. 

PURPOSE 

• Protect water quality 

• Protect air quality 

• Provide fertility for crop, forage, fiber 

production and forest products 

• Improve or maintain soil structure 

• Provide feedstock for livestock 

• Provide a source of energy 

CONDITIONS WHERE PRACTICE APPLIES 

This practice applies where agricultural wastes 

including animal manure and contaminated 

water from livestock and poultry operations; 

solids and wastewater from municipal 

treatment plants; and agricultural processing 

residues are generated, and/or utilized 

CRITERIA 

General Criteria Applicable to All Purposes

All federal, state and local laws, rules and 

regulations governing waste management, 

pollution abatement, health and safety shall be 

strictly adhered to. The owner or operator shall 

be responsible for securing all required permits 

or approvals related to waste utilization, and for 

operating and maintaining any components in 

accordance with applicable laws and 

regulations. 

Use of agricultural wastes shall be based on at 

least one analysis of the material during the 

time it is to be used. In the case of daily 

spreading, the waste shall be sampled and 

analyzed at least once each year. As a 

minimum, the waste analysis should identify 

nutrient and specific ion concentrations. 

Where the metal content of municipal 

wastewater, sludge, septage and other 

agricultural waste is of a concern, the analysis 

shall also include determining the concentration 

of metals in the material. 

When agricultural wastes are land applied, 

application rates shall be consistent with the 

requirements of the NRCS conservation 

practice standard for nutrient management 

(590). 

Where agricultural wastes are to be spread on 

land not owned or controlled by the producer, 

the waste management plan, as a minimum, 

shall document the amount of waste to be 

transferred and who will be responsible for the 

environmentally acceptable use of the waste. 

Records of the use of wastes shall be kept a 

minimum of five years as discussed in 

OPERATION AND MAINTENANCE, below. 

Additional Criteria to Protect Water Quality

All agricultural waste shall be utilized in a 

manner that minimizes the opportunity for 

contamination of surface and ground water 

supplies. 
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the current version of this standard, contact the Natural Resources Conservation Service 

Agricultural waste shall not be land-applied on 

soils that are frequently flooded, as defined by 

the National Cooperative Soil Survey, during 

the period when flooding is expected. 

When liquid wastes are applied, the application 

rate shall not exceed the infiltration rate of the 

soil, and the amount of waste applied shall not 

exceed the moisture holding capacity of the soil 

profile at the time of application. Wastes shall 

not be applied to frozen, snow-covered or 

saturated soil if the potential risk for runoff 

exists. The basis for the decision to apply 

waste under these conditions shall be 

documented in the waste management plan. 

Additional Criteria to Protect Air Quality

Incorporate surface applications of solid forms 

of manure or other organic by-products into the 

soil within 24 hours of application to minimize 

emissions and to reduce odors. 

When applying liquid forms of manure with 

irrigation equipment select application 

conditions where there is high humidity, little/no 

wind blowing, a forthcoming rainfall event 

and/or other conditions that will minimize 

volatilization losses into the atmosphere. The 

basis for applying manure under these 

conditions shall be documented in the nutrient 

management plan. 

Handle and apply poultry litter or other dry 

types of animal manure or other organic byproducts when weather conditions are calm 

and there is less potential for blowing and 

emission of particulates in the atmosphere. 

The basis for applying manure under these 

conditions shall be documented in the nutrient 

management plan. 

When sub-surface applied using an injection 

system, waste shall be placed at a depth and 

applied at a rate that minimizes leaks onto the 

soil surface, while minimizing disturbance to 

the soil surface and plant community. 

All materials shall be handled in a manner to 

minimize the generation of particulate matter, 

odors and greenhouse gases. 

Additional Criteria for Providing Fertility for 

Crop, Forage and Fiber Production and 

Forest Products

Where agricultural wastes are utilized to 

provide fertility for crop, forage, fiber production 

and forest products, the practice standard 

Nutrient Management (590) shall be followed. 

Where municipal wastewater and solids are 

applied to agricultural lands as a nutrient 

source, the single application or lifetime limits 

of heavy metals shall not be exceeded. The 

concentration of salts shall not exceed the level 

that will impair seed germination or plant 

growth. 

Additional Criteria for Improving or 

Maintaining Soil Structure

Wastes shall be applied at rates not to exceed 

the crop nutrient requirements or salt 

concentrations as stated above. 

Residue management practices shall be used 

for maintenance of soil structure. 

Additional Criteria for Providing Feedstock 

for Livestock

Agricultural wastes to be used for feedstock 

shall be handled in a manner to minimize 

contamination and preserve its feed value. 

Chicken litter stored for this purpose shall be 

covered. A qualified animal nutritionist shall 

develop rations that utilize wastes. 

Additional Criteria for Providing a Source of 

Energy

Use of agricultural waste for energy production 

shall be an integral part of the overall waste 

management system. 

All energy producing components of the system 

shall be included in the waste management 

plan and provisions for utilization of residues of 

energy production identified. 

Where the residues of energy production are to 

be land-applied for crop nutrient use or soil 

conditioning, the criteria listed above shall 

apply. 
3/15/2010 Chesapeake Bay Executive Order Section 502 Guidance — Do Not Cite or Quote — 

NRCS, NHCP 

October 2003 

Chapter 2. Agriculture 2-163 

Conservation practice standards are reviewed periodically, and updated if needed. To obtain 

the current version of this standard, contact the Natural Resources Conservation Service 

CONSIDERATIONS 

The effect of Waste Utilization on the water 

budget should be considered, particularly 

where a shallow ground water table is present 

or in areas prone to runoff. Limit waste 

application to the volume of liquid that can be 

stored in the root zone. 

Agricultural wastes contain pathogens and 

other disease-causing organisms. Wastes 

should be utilized in a manner that minimizes 

their disease potential. 

Priority areas for land application of wastes 

should be on gentle slopes located as far as 

possible from waterways. When wastes are 

applied on more sloping land or land adjacent 

to waterways, other conservation practices 

should be installed to reduce the potential for 

offsite transport of waste. 

It is preferable to apply wastes on pastures and 

hayland soon after cutting or grazing before regrowth has occurred. 

Minimize environmental impact of land-applied 

waste by limiting the quantity of waste applied 

to the rates determined using the practice 

standard Nutrient Management (590) for all 

waste utilization. 

Consider the net effect of waste utilization on 

greenhouse gas emissions and carbon 

sequestration. 

PLANS AND SPECIFICATIONS 

Plans and specifications for Waste Utilization 

shall be in keeping with this standard and shall 

describe the requirements for applying the 

practice to achieve its intended purpose. 

The waste management plan is to account for 

the utilization or other disposal of all animal 

wastes produced, and all waste application 

areas shall be clearly indicated on a plan map. 

OPERATION AND MAINTENANCE 

Records shall be kept for a period of five years 

or longer, and include when appropriate: 

• Quantity of manure and other agricultural 

waste produced and their nutrient content. 

• Soil test results. 

• Dates and amounts of waste application 

where land applied, and the dates and 

amounts of waste removed from the 

system due to feeding, energy production 

or export from the operation. 

• Describe climatic conditions during waste 

application such as: time of day, 

temperature, humidity, wind speed, wind 

direction and other factors as necessary. 

• Waste application methods. 

• Crops grown and yields (both yield goals 

and measured yield). 

• Other tests, such as determining the 

nutrient content of the harvested product. 

• Calibration of application equipment. 

The operation and maintenance plan shall 

include the dates of periodic inspections and 

maintenance of equipment and facilities used 

in waste utilization. The plan should include 

what is to be inspected or maintained, and a 

general time frame for making necessary 

repairs.