The mknedat takes the year specified on the command line, and produces output for that year in the ne subdirectory.
The annual total irrigation pumping for groundwater only and commingled lands are accumulated on a cell by cell basis. Monthly pumping is obtained by distributing the annual pumping to individual months according to the following monthly distribution.
| Month | Fraction |
|---|---|
| Jan | 0 |
| Feb | 0 |
| Mar | 0 |
| Apr | 0 |
| May | 0 |
| Jun | 0.147 |
| Jul | 0.320 |
| Aug | 0.328 |
| Sep | 0.205 |
| Oct | 0 |
| Nov | 0 |
| Dec | 0 |
Monthly pumping values are stored in files named ne/yyyy.mm.pmp where yyyy is the year and mm is the month from 01 to 12. No files are produced for months without pumping
Return flows from exclusively groundwater pumping are calculated as 20 percent of the pumped amount. The return flow occurs in the same cell as the pumping.
Return flows for exclusively surface water systems are calculated as the per system return flow fraction times the surface water application volume per cell. The system return flow fraction is obtained from the system type identifier.
| System Identifier | System Name | Return Flow Fraction |
|---|---|---|
| Federal Canals | ||
| 800 | Culbertson | 0.246 |
| 801 | Culbertson Extension | 0.246 |
| 802 | Meeker-Driftwood | 0.246 |
| 803 | Bartley | 0.246 |
| 804 | Red Willow | 0.246 |
| 805 | Cambridge | 0.246 |
| 807 | Franklin | 0.287 |
| 808 | Naponee | 0.287 |
| 809 | Franklin Pump | 0.287 |
| 810 | Superior | 0.2542 |
| 811 | Courtland | 0.1886 |
| Private Canals | ||
| 812 | Haigler | 0.4 |
| 813 | Champion | 0.4 |
| 814 | Riverside | 0.4 |
| CNPPID Canals | ||
| 816 | Jeffrey Hydro | 0.4 |
| 817 | Jeffrey Hydro to J1 Hydro | 0.4 |
| 818 | J2 to the Platte | 0.4 |
| 819 | Phelps (2000-) | 0.3 |
| 820 | E65 (2000-) | 0.3 |
| 821 | E67 (2000-) | 0.3 |
| Platte Private Wells | ||
| 822 | Sixmile | 0.4 |
| 823 | Thirtymile | 0.4 |
| 824 | Orchard | 0.4 |
| 826 | Western | 0.4 |
| NPPD Canals | ||
| 825 | NPPD | 0.4 |
| Miscellaneous | ||
| 899 | Private Canal Losses to Fields | 0.4 |
| 9001-9999 | River Pumpers | 0.4 |
For commingled acres, the surface water return flow fraction is calculated just like the surface water only fraction. For groundwater application on commingled acres, the rate of groundwater application is calculated for each county as the county total volume of commingled groundwater pumping divided by the county total commingled acreage. The groundwater return flow for commingled lands is then calculated as the groundwater commingled application rate for the county times the surface water commingled acres for the cell time the surface water return flow fraction for the system specified with the surface water commingled data.
The exclusively groundwater plus groundwater portion of commingled return flows are stored in files named ne/yyyy.mm.rcg. The exclusively surface water plus surface water portion of commingled return flows are stored in files named ne/yyyy.mm.rcs.
The exclusively groundwater, exclusively surface water and commingled irrigated acreage are stored in files named ne/yyyy.agw, ne/yyyy.asw and ne/yyyy.aco, respectively. Note that the county total commingled groundwater and commingled surface water acreage must match, however, at the cell level, the surface water commingled acres and groundwater commingled acres does not match. This is because the location of the groundwater acres are based on the location of the well, while the surface water location is based on the location of the irrigated lands. Therefore the surface water commingled acreage is used in the precipitation recharge calculation.
The mknedat program summarizes the following items on a county by county basis to the file necounty.dat: