# Feedlot Drainage System Design and Runoff Control ## Key Takeaways - **Prioritize clean water diversion:** Divert uncontaminated sources like roof runoff and upslope surface water away from feedlot pens to significantly reduce the volume of contaminated runoff requiring management. - **Pen grading is critical:** Implement a consistent pen slope of 2% to 4% towards a collection point to ensure surface dryness, prevent mud formation, and facilitate controlled runoff movement. - **Comprehensive collection and storage:** Design a system that collects runoff from the entire lot, utilizing a settling basin to remove solids and a storage pond sized for the largest expected runoff events, including snowmelt and sludge accumulation. - **Regulatory compliance and professional consultation:** Understand and adhere to local, state, or provincial regulations regarding permits, design standards, and reporting requirements, and consult with professional engineers or extension agents for design review before construction. - **Proactive management and recordkeeping:** Implement a year-round management schedule for monitoring, inspections, and maintenance, and maintain detailed records of rainfall, land application, and system upkeep to ensure operational efficiency and compliance. --- Rain and snowmelt falling on a cattle feedlot do not simply disappear. They become runoff that carries manure, urine, feed particles, and sediment across the pen surface and toward the lowest point of your operation. Without a deliberate drainage system, that runoff moves off your property, into drainageways, and potentially into streams, wells, or neighboring land. This article explains how to plan, design, and manage a feedlot drainage system that controls runoff, protects water quality, and keeps your operation in compliance with environmental expectations. It is written for cattle producers, feedlot managers, and agricultural professionals who are planning a new feedlot, expanding an existing one, or correcting drainage problems that have developed over time. ## At a Glance - **Divert clean water away first.** Roofs, roads, and undisturbed land should drain around the feedlot, not through it. This reduces the volume of contaminated water you must manage. - **Slope pens 2 to 4 percent.** A consistent slope toward a collection point keeps the surface drier and moves runoff where you want it. - **Collect runoff from the entire lot.** A settling basin removes solids, and a storage pond holds the liquid until you can apply it to land. - **Size your storage for your climate.** You need enough capacity for the largest runoff events plus room for snowmelt and sludge accumulation. - **Know your regulations.** Permits, design standards, and reporting requirements vary by location. Contact your state or provincial agricultural agency before you build. - **Keep records.** Rainfall, land application, and maintenance logs protect you in an inspection and help you manage the system better. - **Call for help when needed.** A professional engineer or extension agent should review your design before construction, not after problems appear. ## Understanding Feedlot Runoff and Why It Matters A feedlot concentrates animals, manure, and feed in a small area. That concentration is what makes the operation efficient, but it also creates a water management challenge. When rain falls on a pen, it picks up soluble nutrients, organic matter, and pathogens from the manure pack and carries them with it. The result is a liquid that is very different from ordinary rainwater. It has high levels of nitrogen, phosphorus, biochemical oxygen demand, and bacteria. If that liquid reaches a stream or groundwater, it can harm aquatic life, contaminate drinking water supplies, and create algae blooms. The term feedlot runoff control describes the full set of practices you use to keep contaminated water on your property and out of surface water and groundwater. A feedlot drainage system is the physical infrastructure that makes that possible. It includes pen grading, collection channels, settling basins, storage ponds, and the land application equipment you use to dispose of the captured liquid. Runoff management is not just an environmental issue. It is also a production issue. Pens that hold water create mud. Mud increases animal stress, raises the risk of foot rot and other infections, reduces feed intake, and makes cattle harder to handle. A well-drained pen keeps cattle cleaner, drier, and more comfortable, which supports better gains and fewer health problems. The design approach that works for a 100-head operation in a dry climate will not work for a 5,000-head operation in a region with 40 inches of annual rainfall. Your drainage system must match your animal numbers, your climate, your topography, and your land base. The sections that follow walk through the planning process step by step. ## Step 1: Assess Your Site and Define Your Goals Before you move any dirt or pour any concrete, you need a clear picture of your site and a clear statement of what the drainage system must accomplish. Start with a site assessment that covers these areas. ### Topography and Soils Walk the entire area where you plan to build or expand. Note the direction of natural drainage. Identify any low spots where water already collects. Look at the slope of the land and think about how that slope will affect pen construction and water movement. Soil type matters more than most producers realize. Sandy soils drain quickly and may allow water to move down to groundwater. Clay soils drain slowly and may cause water to pond on the surface. Both situations have implications for your design. A soil test and a percolation test will tell you how your soil behaves. Your local soil and water conservation district or extension office can help you interpret the results. ### Climate and Rainfall Patterns Your drainage system must handle the rainfall patterns typical of your area, not just the annual average. A 10-year, 24-hour rainfall event is a common design standard. Your local weather service or agricultural agency can provide the number for your county. In colder regions, you also need to account for snowmelt. A sudden warm spell in March can release more water than any single rainstorm. ### Distance to Water and Neighbors Map the location of streams, ditches, ponds, wells, and property lines. Your drainage system must keep runoff away from all of them. Most regulations require a buffer distance between a feedlot or its storage pond and any surface water or well. Know those distances before you lay out your pens. ### Animal Numbers and Future Plans Design for the number of animals you expect to have at full capacity, not the number you have today. If you think you might expand in five years, it is cheaper to build the drainage system for the larger operation now. Retrofitting a drainage system is far more expensive than building it correctly the first time. ### Regulatory Requirements Contact your state department of agriculture, your state environmental agency, or your provincial agricultural ministry early in the planning process. Ask what permits you need, what design standards apply, and what inspections you can expect. The rules vary widely. Some states require a permit for any concentrated animal feeding operation. Others have specific engineering standards for settling basins and storage ponds. Getting this information before you design saves you from costly rework later. ## Step 2: Design the Clean Water Diversion System The first principle of feedlot runoff control is simple: keep clean water clean. Rain that falls on a roof, a road, or a grassy hillside does not need treatment. If you can keep that water from ever entering your pens, you reduce the volume of contaminated runoff you must collect and store. This is almost always the cheapest and most effective part of a drainage system. ### Roof Water Gutters and downspouts on feed barns, commodity sheds, and equipment buildings should carry roof water away from the lot. Direct the water to a grassy area, a diversion channel, or a separate clean water outlet. Do not let roof water discharge into a pen or onto the manure pack. ### Diversion Channels and Berms A diversion channel or berm is a shallow ditch or earthen ridge that intercepts runoff from higher ground and routes it around the feedlot. It is typically built along the uphill side of the pens. The channel should have enough slope to move water quickly but not so much slope that it erodes. A slope of 0.5 to 1.5 percent is usually adequate. The diverted water can flow to a natural drainageway, a grassed waterway, or a holding area, as long as it never mixes with feedlot runoff. Make sure the diversion channel has a stable outlet that will not erode or create a new problem downstream. ### Road Drainage Roads around the feedlot can generate a surprising amount of runoff, especially if they are gravel or dirt. Grade roads so that water sheds to the sides and flows into ditches or diversion channels. Keep road ditches separate from the feedlot drainage system. ### Grading the Feedlot Surface Once clean water is diverted, you can focus on the pens themselves. The goal is a surface that sheds water consistently toward a collection point. A slope of 2 to 4 percent is the standard recommendation for feedlot pens. This is enough slope to move water without being so steep that cattle struggle to walk or lie down comfortably. The slope should be uniform across the pen. Low spots and depressions hold water and create mud. A laser-guided scraper or grader can create the precise surface you need. If you are building on land that has variable topography, you may need to cut and fill to create a consistent grade. The direction of slope depends on your overall layout. In a typical design, pens slope toward a central collection channel or alley. That channel carries the runoff to a settling basin and then to a storage pond. Some operations use a perimeter collection system, where pens slope toward the outside edges of the lot. Choose the layout that fits your site and your management style. ## Step 3: Design the Runoff Collection System The collection system is the network of channels and pipes that move runoff from the pens to the treatment and storage structures. It must be sized to handle the peak flow from your design storm, and it must be built so that solids do not settle out and clog the system. ### Collection Channels Open channels are the most common collection method in feedlots. They are simple to build, easy to inspect, and can handle large flows. The channel should be sized so that water moves at a velocity that keeps solids in suspension. A velocity of at least 2 feet per second during a design storm is a common guideline. Slower velocities allow manure solids to drop out and accumulate in the channel. The channel bottom should be concrete or another hard surface if possible. Earthen channels are cheaper but harder to clean and more prone to erosion. If you use an earthen channel, line it with a geotextile fabric or riprap in areas where velocity is high. ### Grates and Screens Where runoff enters a pipe or a settling basin, install a grate or screen to catch large solids. This prevents clogs and makes the system easier to maintain. The grate should be removable so you can clean it regularly. ### Pump Stations Some feedlots need to pump runoff from a low collection point to a higher storage area. A pump station with a solids-handling pump can move the liquid and the small solids that pass through the grate. The pump should be sized for the peak flow you expect, and it should have a backup or a clear maintenance plan. A pump failure during a storm can cause runoff to back up and overflow. ## Step 4: Design the Settling Basin A settling basin is a structure that slows the runoff long enough for solids to settle out. It is the first stop for contaminated water after it leaves the pens. The basin removes the heavy solids that would otherwise accumulate in your storage pond and make it harder to pump and land-apply. ### How a Settling Basin Works Runoff enters the basin at one end, slows down, and the solids drop to the bottom. The relatively clear liquid flows out the other end and moves to the storage pond. The solids that accumulate in the basin must be removed periodically and spread on cropland or composted. ### Sizing the Settling Basin The size of the settling basin depends on the volume of runoff you expect and the amount of solids you need to remove. A common rule of thumb is to provide at least 1 cubic foot of settling basin volume for every 100 square feet of contributing drainage area. This is a starting point, not a substitute for a proper engineering calculation. Your local regulations may specify a different standard. The basin should be at least 2 to 3 feet deep to provide adequate settling time. The length-to-width ratio should be at least 2 to 1, with the inlet at one end and the outlet at the other. This forces the water to travel a longer path and gives solids more time to settle. ### Basin Construction and Maintenance Build the basin with concrete or an impermeable liner to prevent seepage into groundwater. The basin walls should be sloped so you can get equipment in to clean it. A ramp at one end allows a skid steer or tractor to reach the accumulated solids. Plan to clean the settling basin at least once a year, usually in late summer or early fall when the basin is dry. The removed solids are a valuable fertilizer. Test them for nutrient content and apply them according to your nutrient management plan. ## Step 5: Design the Storage Pond The storage pond is the heart of your feedlot runoff control system. It holds the liquid that comes out of the settling basin until you can apply it to land. The pond must have enough capacity for the runoff you generate, and it must be built to prevent leaks. ### Types of Storage Ponds Storage ponds come in two basic types: excavated and embankment. An excavated pond is dug into the ground, with the excavated material used to build berms around the edges. An embankment pond is built by constructing a dam or dike to impound water. Many feedlots use a combination of both. The type you choose depends on your site. Excavated ponds work well in flat terrain. Embankment ponds work well where there is a natural depression or a slope you can use. A professional engineer can help you decide which type fits your site. ### Sizing the Storage Pond This is the most important calculation in your entire drainage system. The pond must hold the runoff from your design storm, plus the runoff from a typical year, plus the sludge that accumulates over time. Most regulations require storage capacity for the runoff from a 25-year, 24-hour storm in addition to normal operating volume. Some regions require more. To size your pond, you need to estimate the volume of runoff your feedlot will produce. A common method is the Natural Resources Conservation Service curve number approach, which accounts for your rainfall, your drainage area, and the characteristics of your surface. Your local NRCS office or extension engineer can help you run this calculation. As a rough starting point, the runoff from a feedlot in a region with 30 inches of annual rainfall can range from 5 to 15 inches per year, depending on your surface and management. Multiply that by the area of your lot to get an annual volume. Then add the volume from your design storm. Then add space for sludge accumulation, typically 1 to 2 feet of depth over the life of the pond. ### Pond Construction The pond must be impermeable to prevent seepage into groundwater. If your soil is naturally tight, such as clay, it may provide adequate sealing. If your soil is sandy or has high permeability, you will need to install a liner. Compacted clay liners, geomembrane liners, and bentonite amendments are common options. Your engineer or local agency can recommend the right approach for your soil. The pond walls should have a slope of 3 to 1 or flatter for stability. The bottom should be level or gently sloped to a low point where a pump can reach the liquid. Include a freeboard of at least 1 to 2 feet above the maximum design water level to prevent wave action from overtopping the berm. ### Pond Access and Safety Build a ramp or a reinforced pad so you can get a pump and hose into the pond for land application. Install a fence around the pond to keep livestock and people out. Post warning signs. A storage pond is not a place for swimming or livestock watering, and it should be treated as a confined space for safety purposes. ## Step 6: Plan the Land Application System The storage pond is not a permanent disposal site. It is a temporary holding tank. The liquid in the pond must be removed regularly and applied to cropland where the nutrients can be used by plants. This is the final step in the runoff control cycle. ### Determine Your Land Base You need enough land to receive the liquid at agronomic rates. The amount of land depends on the nutrient content of the liquid, the nutrient needs of your crops, and your local regulations. A common approach is to base the application rate on nitrogen needs, since nitrogen is often the limiting nutrient. But you also need to watch phosphorus levels, since repeated applications can build phosphorus in the soil to levels that harm water quality. ### Application Methods Liquid manure can be applied with a tanker spreader and injection equipment, or it can be pumped through irrigation equipment. Injection or incorporation into the soil is the best method because it reduces odor, prevents nutrient losses to the air, and keeps the nutrients where the crop can use them. Surface application without incorporation is acceptable on some soils and slopes, but it carries a higher risk of runoff and odor complaints. ### Timing Apply the liquid when the soil is dry enough to support equipment and when the crop can use the nutrients. Spring and fall are the most common application times. Avoid application on frozen or snow-covered ground in most areas, since the runoff risk is high. Your local regulations may specify application windows and setbacks from water bodies. ### Nutrient Testing Test the liquid before each application. The nutrient content can vary widely depending on the time of year, the amount of rain, and the solids content. A simple test for nitrogen, phosphorus, and potassium tells you how much to apply. Your extension office can tell you where to send samples. ## Step 7: Manage the System Through the Seasons A feedlot drainage system requires year-round attention. Each season brings different challenges and different maintenance tasks. ### Spring Spring is the most critical season for runoff control in cold climates. Snowmelt can release a large volume of water in a short time, and frozen ground prevents infiltration. Check your diversion channels early to make sure they are clear of ice and snow. Inspect the settling basin and storage pond for damage from freeze-thaw cycles. Repair any cracks or erosion before the spring rains arrive. Spring is also the time to start planning your first land application. The soil may be too wet early in the season, so watch the weather and the field conditions carefully. ### Summer Summer brings the highest-intensity rainstorms and the highest risk of a large runoff event. Inspect your collection channels and grates before each forecast storm if possible. Remove any solids that have accumulated. Check the storage pond water level and make sure you have adequate capacity for the coming rain. Summer is also the season for cleaning the settling basin. The basin is typically dry in late summer, which makes it easier to access. Remove the accumulated solids and spread them on cropland or compost them. ### Fall Fall is the primary land application season in many areas. Apply the stored liquid after harvest, when the soil is dry and the crop residue can help hold the nutrients in place. Test the soil and the liquid to determine application rates. Fall is also a good time to do major repairs. The ground is still workable, and you have time before the ground freezes. Regrade pens if needed, repair erosion in channels, and address any problems that developed during the summer. ### Winter Winter is the season of prevention. Keep the drainage system clear of snow and ice so it can handle a midwinter thaw. Do not apply liquid to frozen ground unless your regulations allow it and conditions are safe. Use the winter months to review your records, plan next year's maintenance, and schedule any improvements. ## Common Mistakes in Feedlot Drainage Design Many feedlot drainage problems come from the same few errors. Knowing these mistakes can help you avoid them. ### Undersizing the Storage Pond This is the most common and most serious mistake. Producers underestimate the volume of runoff their feedlot produces, especially in wet years. The result is an overflow that sends contaminated water off the property. When in doubt, build the pond larger. The cost of extra capacity is small compared to the cost of a violation or a lawsuit. ### Forgetting About Snowmelt A system designed only for rainfall will fail in a cold climate. Snowmelt can produce a large volume of water over several days, and it often comes when the ground is frozen and the soil cannot absorb anything. Make sure your storage pond has capacity for the snowmelt season, not just the growing season. ### Ignoring Clean Water Diversion Some producers build a complete collection and storage system but forget to divert clean water away from the lot. The result is a storage pond that fills with rainwater that never touched the pens, wasting capacity and requiring more land application than necessary. Diverting clean water is the cheapest and easiest part of the system, and it has the biggest payoff. ### Poor Pen Grading A pen that looks flat to the eye can still have low spots that hold water. These low spots create mud, increase animal health problems, and make the drainage system work harder than it should. Take the time to grade pens properly with laser-guided equipment, and regrade them periodically as the surface settles. ### Using an Earthen Settling Basin Without a Liner An unlined settling basin will seep. That seepage can carry nutrients and bacteria into groundwater. If your soil is not naturally tight, install a liner. The cost is modest compared to the environmental risk. ### Neglecting Maintenance A drainage system is not a set-and-forget investment. Grates clog, channels erode, ponds accumulate sludge, and pumps fail. A system that is not maintained will eventually fail, and the failure will happen during the worst weather. Build a maintenance schedule and stick to it. ### Not Keeping Records Regulators expect to see records of your system's operation. They want to know when you applied liquid, how much you applied, to which fields, and at what nutrient rates. They also want to see inspection and maintenance logs. If you cannot produce these records, you are at a disadvantage in any inspection or dispute. ## Decision Thresholds: When to Build, Retrofit, or Rebuild Not every feedlot needs the same level of drainage infrastructure. The right system for your operation depends on several factors. Here are some decision thresholds to guide your planning. ### Small Operations with Low Animal Density If you have a small feedlot, fewer than 300 head, and you are in an area with low rainfall, you may be able to manage runoff with a simpler system. A well-graded pen that drains to a vegetated filter area may be sufficient. Check your local regulations, because some areas require more even for small operations. ### Medium Operations If you have 300 to 1,000 head, you likely need a settling basin and a storage pond. The storage volume can be modest in dry climates, but you still need the infrastructure to capture and hold runoff. A professional engineer should review your design. ### Large Operations If you have more than 1,000 head, you need a full system with clean water diversion, graded pens, collection channels, a properly sized settling basin, and a storage pond with adequate capacity. You also need a nutrient management plan and a land application program. Most large operations are subject to state or federal permitting, and you should expect regular inspections. ### Operations with a History of Problems If you have had runoff leaving your property, complaints from neighbors, or a notice of violation, do not patch the system. Take it as a signal that your design is fundamentally inadequate. Hire an engineer to assess the whole system and recommend a comprehensive fix. ### Operations Near Water If you are within a few hundred feet of a stream, river, lake, or well, your system needs a higher level of protection. You may need a larger storage pond, a liner on all structures, and additional setbacks. Do not cut corners in this situation. ## Monitoring, Inspections, and Recordkeeping A drainage system is only as good as the management behind it. Regular monitoring and complete records protect you in an inspection and help you catch problems before they become serious. ### What to Monitor Check the storage pond water level after every significant rain. Know how much capacity you have left. If the pond is getting full, plan a land application soon. Check the settling basin for accumulated solids and clean it before the solids reduce its capacity. Walk the collection channels and diversion channels after storms to look for erosion, blockages, or damage. Inspect the pump and the grates for wear and clogs. ### What to Record Keep a log of every inspection and every maintenance activity. Record the date, the weather, what you found, and what you did. Keep records of every land application, including the field, the acres, the application rate, and the nutrient content of the liquid. Keep your rainfall records, either from your own gauge or from a nearby weather station. ### Preparing for an Inspection When an inspector arrives, be ready to show them your records. Walk them through the system and explain how it works. If the inspector finds a problem, do not argue. Ask for guidance on how to fix it and set a timeline for the correction. A cooperative attitude goes a long way. ### Self-Audits Conduct your own audit at least once a year. Walk the entire system from the pens to the storage pond and look for anything that is not working as designed. Use a checklist so you do not miss anything. Take photos for your records. ## When to Call a Veterinarian or Extension Agent Most drainage system decisions are not veterinary decisions. But there are situations where you should involve a veterinarian or an extension agent. ### Animal Health Concerns If you see an increase in foot rot, lameness, mastitis, or other conditions that can be linked to mud and wet conditions, your drainage system may be contributing to the problem. Call your veterinarian to diagnose the health issue and help you determine whether pen conditions are a factor. Fixing the drainage may be part of the treatment plan. ### Water Quality Testing If you suspect that runoff from your feedlot has reached a well or a stream, test the water. Your extension office can tell you what to test for and where to send samples. If the test shows contamination, contact your extension agent or your state environmental agency for guidance on corrective action. ### Design Questions If you are planning a new system or a major expansion, call your extension agent before you build. They can provide design guidance, point you to local resources, and help you avoid common mistakes. They can also connect you with a professional engineer who specializes in agricultural drainage. ### Regulatory Questions If you are unsure about the rules that apply to your operation, call your extension agent or your state agricultural agency. Do not rely on what a neighbor told you or what you read online. The rules change, and they vary by location. ## Frequently Asked Questions ### How much slope do feedlot pens need for good drainage? A slope of 2 to 4 percent is the standard recommendation. This is enough slope to move water off the pen surface without creating a slope that is uncomfortable for cattle. The slope should be uniform across the pen, with no low spots or depressions. Use laser-guided grading equipment to achieve a consistent surface. ### How big should my runoff storage pond be? The size depends on your rainfall, your lot area, and your local regulations. A common approach is to size the pond to hold the runoff from a 25-year, 24-hour storm plus the normal operating volume from a typical year, plus space for sludge accumulation. Have a professional engineer run the calculation for your specific site. When in doubt, build it larger than you think you need. ### Can I let feedlot runoff flow into a grassy area instead of building a storage pond? In some areas and for some small operations, a vegetated filter area may be acceptable. The grass traps solids and the vegetation takes up nutrients as the water infiltrates. However, this approach does not work in all soils, on all slopes, or in all climates. Check with your local agency before relying on a filter area. Many operations find that a settling basin and storage pond are necessary for reliable runoff control. ### How often do I need to clean the settling basin? Most operations clean the settling basin once a year, usually in late summer or early fall when the basin is dry. If you have a large operation, frequent storms, or a lot of solids in your runoff, you may need to clean it more often. Inspect the basin regularly and clean it before the accumulated solids reduce its capacity. ### What do I do with the liquid from the storage pond? You apply it to cropland at agronomic rates. Test the liquid to determine its nutrient content, test your soil to know what the crop needs, and apply the liquid at a rate that meets the crop's needs without overapplying. Inject or incorporate the liquid into the soil when possible to reduce odor and runoff risk. ### Do I need a permit for my feedlot drainage system? That depends on your location and the size of your operation. Many states require a permit for concentrated animal feeding operations. Some require permits for any storage pond. Contact your state department of agriculture or environmental agency early in the planning process to find out what applies to you. ### What should I do if my storage pond is about to overflow? If the pond is near capacity and more rain is coming, you need to act quickly. Apply the liquid to an available field if conditions allow. If you cannot apply, contact your local agency to discuss your options. Do not let the pond overflow. An overflow is a violation that can have serious consequences. ### How much does a feedlot drainage system cost? The cost varies widely depending on the size of the operation, the site conditions, and the type of system. A small system with a settling basin and a small pond might cost tens of thousands of dollars. A large system with extensive grading, concrete channels, and a large lined pond can cost much more. Get quotes from contractors in your area and factor in the cost of engineering services. The cost of not building a system can be higher, in the form of fines, legal liability, and environmental damage. ## Related Farming Guides This section will be populated with links to related guides on feedlot management, manure handling, nutrient management planning, and environmental compliance for cattle operations. ## Related Clinical & Scientific Guides * [Cattle Head Gate Selection and Adjustment](/knowledge/animal-farming/beef-cattle/cattle-head-gate-selection-and-adjustment) * [Beef Cattle Handling Facility Flow](/knowledge/animal-farming/beef-cattle/beef-cattle-handling-facility-flow) * [Beef Cattle Maternity Pen Design: Comfort and Monitoring](/knowledge/animal-farming/beef-cattle/beef-cattle-maternity-pen-design-comfort-monitoring) ## References - Beef Cattle Research Council: https://www.beefresearch.ca/ - USDA APHIS Cattle Health: https://www.aphis.usda.gov/livestock-poultry-disease/cattle - WOAH Terrestrial Animal Health Code: https://www.woah.org/en/what-we-do/standards/codes-and-manuals/terrestrial-code-online-access/ - FAO Animal Production and Health: https://www.fao.org/animal-production/en/ - WOAH (World Organisation for Animal Health): https://www.woah.org/en/home/ > This article is educational and is not a substitute for veterinary diagnosis, treatment, public-health guidance, or regulatory reporting.