Instructions
Action 1Use the Draw a Polygon (
) feature to outline the subsurface-drained area served by a single outlet.
Proceed to next step.
Edit the streams and watersheds using the utilities in the bottom-right corner.
Instructions
Action 1Use the Draw a Polygon (
) feature to outline the subsurface-drained area served by a single outlet.
Use the Draw a Marker (
) feature to identify the location of the outlet control structure.
Use the Draw a Polyline (
) feature to identify the main pipe.
Fill the table and proceed to Step 3 to view the impacted area.
| Impact Area Determination Method | |
| User-specified elevation rise |
Instructions
Action 1Use the Draw a Polygon (
) feature to outline the subsurface-drained area served by a single outlet.
Use the Draw a Polyline (
) feature to identify the length of the distribution pipe.
Use the Draw a Marker (
) feature to identify the location of the outlet control structure.
Enter values in the table and click Generate Profile. A Passed Design is required to proceed.
| Depth of distribution pipe at structure (ft) | |
| Minimum allowable depth (ft) | |
| Maximum allowable depth (ft) | |
| Pipe location relative to structure | |
| One side: Grade of distribution pipe (%) | |
| Left side: Grade of distribution pipe (%) | |
| Right side: Grade of distribution pipe (%) |
1b. Manual Soil Inputs
2. Cropping System Info
| Cropping system | |||||
| Corn planting date | Will you use no-till? | ||||
| Corn growing days | |||||
| Soybean planting date | |||||
| Soybean growing days |
3. Drainage System Properties
Drainage Design
| Drain depth (ft) | ||
| Drain spacing (ft) | ||
| Size & type of lateral drain pipe | ||
| Drainage coefficient (in/day) |
| Will you split runs in the upgraded design? | ||
| Existing drain spacing (ft) | ||
| Existing drainage coefficient (in/day) |
Outlet Management Settings
| Corn | Soybean | ||
|---|---|---|---|
Preparing for spring planting | |||
| Date to lower outlet elevation before planting | |||
Management during growing season | |||
| Depth from soil surface to raised outlet (in) | |||
| Date to raise outlet elevation after planting | |||
Preparing for fall harvest | |||
| Date to lower outlet elevation before harvest | |||
Management during non-growing season | |||
| Depth from soil surface to raised outlet (in) | |||
| Date to raise outlet elevation after harvest | |||
Check box to maintain a constant weir setting year-round | |||
Action: Click on the Generate Profile button. A Passed Design is required to proceed.![]()
Optional: Click on the Generate Profile button to see the weir profile.![]()


Please wait while the profile is generated.




4. Simulation Period
Weather data is available from the year 1981 onward (a minimum of 30 years is recommended)
| Simulation start year | |
| Simulation end year | |
| Length of simulation period (years) |
5. System Cost
| Drainage System and Maintenance Costs | |
|---|---|
| Material cost of lateral drain pipe ($/ft) | |
| Installation cost of lateral drain pipe ($/ft) | |
| Expected lifetime of drainage system (years) | |
| Interest rate on average investment per year (%) | |
| Maintenance rate per year (%) | |
| Crop Information for the Subsurface-drained Farm | ||
|---|---|---|
| Corn price ($/bu) | ||
| Soybean price ($/bu) | ||
| Potential corn yield (bu/ac) | ||
| Potential soybean yield (bu/ac) | ||
| Annual corn production cost ($/ac) | ||
| Annual soybean production cost ($/ac) | ||
| Controlled Drainage Costs | |
|---|---|
| Material, freight, and installation cost of control structure ($) | |
| Expected lifetime of the control structure (years) | |
| Interest rate on average investment per year (%) | |
| Maintenance rate per year (%) | |
| Select the Financial Incentives to be Included | |
|---|---|
| Water Quality Information/th> | ||
|---|---|---|
| Average annual nitrate-N concentration in drainage discharge (mg/L) | ||
5. Saturated Buffer Properties
| Length of distribution pipe (ft) | ||
| Maximum buffer width of new design (ft) | ||
| Buffer width of existing system (ft) | ||
| Average depth of distribution pipe (ft) | ||
| Size of main pipe connecting field drainage to structure (in) | ||
| Average water level in the ditch, h2 (ft) | ||
| Equivalent saturated hydraulic conductivity of the buffer soil (in/h) | ||
| Depth to restrictive layer of the buffer soil (ft) | ||
| Effective porosity of the buffer soil (decimal) | ||
| Size & type of distribution pipe | ||
| First-order denitrification coefficient of the buffer soil, Kd (day-1) |

6. Saturated Buffer Cost
| Saturated buffer system and maintenance costs | |
|---|---|
| Material, freight, and installation cost of control structure ($) | |
| Material and installation cost of distribution pipe ($/ft) | |
| Cost of grass seed and its drilling ($/ac) | |
| Expected lifetime of the saturated buffer system (years) | |
| Interest rate on average investment (%) | |
| Maintenance rate, adjusting/replacing stoplogs, grass moving/baling (%) | |
| Select the Financial Incentives to be Included | |
|---|---|
| Water Quality Information | ||
|---|---|---|
| Average annual nitrate-N concentration in drainage discharge (mg/L) | ||