Illinois SWAT+ modeling | SWATGenX
Embarras — USGS 03345000: documented SWAT+ USGS station watershed snapshot with Explorer-aligned maps.
SWATGenX documents a sample SWAT+ watershed model in Illinois for Embarras (USGS 03345000). The overview covers 3868.6 km² with 79467 HRUs and 5456 channels, with corn prominent in the exported land-cover summary, using the same CONUS national data stack as every production build. Review DEM, land-cover, and structure summaries on this page, then open Watershed Explorer to model your own gage or HUC, or browse downloadable packages in the example models catalog.
Part of SWAT+ modeling by stateon SWATGenX: a sample example model for this state, built with the same CONUS national datasets as Watershed Explorer. Browse downloadable example models.
Why watershed modeling matters
Watershed models help connect landscape processes, managed systems, and channel routing to questions about water supply, water quality, and flood timing. SWAT+ represents those linkages over multi-year climate forcing using national soils, land cover, and hydrography. Study-specific calibration, local observations, and endpoint models remain the responsibility of each project team.
Case study basin: Embarras
Below is a documented SWAT+ model-build snapshot for the Embarras watershed—the same export class as Watershed Explorer. The metric strip, maps, charts, NHD flowline-length summary by feature class, and fact tables follow from that committed export.
The metric strip, fact tables, and optional DEM/CDL maps describe the exported SWAT+ workspace for Embarras (HUC8 05120112). NHD-linked stream statistics and PRISM climate headers follow the same conventions as other SWATGenX state sample models across CONUS.
Counties in the basin overlay: Champaign, Clark, Coles, Cumberland, Douglas, Edgar, Effingham, Jasper, Vermilion.
- Runoff timing and climate variability across multi-year forcing
- Channel routing and NHDPlus HR hydrography linkage
- Land cover and HRU discretization for management screening
- Reproducible SWAT+ package delivery via SWATGenX
Basin distributions (Embarras · Illinois)
CDL charts use the same basin-clipped raster summary as Explorer watershed reports. County population bars use US Census county-or-equivalent polygons only (not state, city, or township layers): one published headcount per county that intersects the basin, then summed for screening—not watershed-apportioned density.
CDL land cover (basin clip)
CDL cropland & permanent crops (share)
Population by county (overlay)
Land-cover mix (km², CDL clip)
Climate forcing (Embarras · Illinois)
Monthly climatology from basin PRISM precipitation and temperature plus NSRDB humidity, solar radiation, and wind files. The line is the mean daily value for each calendar month (averaged across all station files and years); the shaded band is the P05–P95 spread of those daily values (2000-01-01 – 2024-12-31). Source grid: 522 PRISM/NSRDB grid cells (4 km).
Precipitation
mm day⁻¹ (PRISM)Relative humidity
% (NSRDB)Solar radiation
MJ m⁻² day⁻¹ (NSRDB)Wind speed*
m s⁻¹ (NSRDB MERRA-2, ~2 m)Daily maximum temperature
°C max (PRISM)Daily minimum temperature
°C min (PRISM)* Wind speed. MERRA-2 at ~2 m above ground (not 10 m hub height). Daily arithmetic mean of 48 thirty-minute NSRDB steps; curves are monthly basin means with P5–P95 spread. NREL documents this for solar forcing, not wind-resource assessment.
Key facts
The first table lists basin id, climate window, CDL and population context, and the two published stream-length definitions (channel routing versus NHD-linked stream GIS). The strip above still carries headline structure counts (HRUs, channels, lakes).
| Metric | Value |
|---|---|
| WBD HU8 name | Embarras |
| USGS site (HUC12 model folder) | 03345000 |
| WBD region (VPUID) | 0512 |
| Watershed area | 3868.56 km² |
| SWAT+ stream GIS segments (NHDPlusID → NHDFlowline) | 5491 |
| Stream length — channel routing (rivs1, projected) | 4264.16 km |
| NHD-linked stream length, GIS projected | 4279.30 km |
| DEM resolution (m) | 29.90 |
| CDL cropland (basin clip) | 3012.44 km² |
| CDL wetland (Woody + Herbaceous) | 28.69 km² |
| CDL developed | 179.75 km² |
| Population (by county, Explorer overlay) | 433,382 |
| Counties (gov. units) | 9 |
| Climate period (PRISM header) | 2000-01-01 – 2024-12-31 |
| Stats exported (UTC) | 2026-05-21 17:08 UTC |
| SWATGenX snapshot ID | 0512/huc12/03345000 |
| Snapshot label | Embarras (Illinois) — usgs_station — exported workspace |
| Model statistics generated (UTC) | 2026-05-21T17:08:35Z |
How to read this table: each row starts from Watershed/Shapes/SWAT_plus_streams.shp, where each segment carries NHDPlusID. Those IDs join to NHDFlowline in the USGS NHDPlus HR HU4 geodatabase (VPUID 0512). Lengths add in EPSG:5070 (planimetric km) and roll up by NHD FType / FCode. Row lengths sum to 4,279.3 km over 5,491 segments.
| NHD class (label) | Length (km) | Share | Segments |
|---|---|---|---|
| Stream / river (intermittent)FType 460 · FCode 46003 | 2,639.07 | 61.7% | 3,055 |
| Stream / river (perennial / general)FType 460 · FCode 46006 | 1,277.67 | 29.9% | 1,245 |
| Artificial path (NHD)FType 558 · FCode 55800 | 319.57 | 7.5% | 1,176 |
| Canal / ditchFType 336 · FCode 33600 | 42.99 | 1% | 15 |
The county total matches the bar chart: county-or-equivalent units only (cities and townships excluded), one Census headcount per county intersecting the basin. Screening context only—not basin density or a regulatory design population.
SWATGenX documented snapshot (usgs_station) for Illinois: model id 0512/huc12/03345000. Values come from the exported SWAT+ workspace plus Explorer-style overlays where present; they support screening and documentation, not regulatory determinations.
What SWATGenX generates
SWATGenX assembles national inputs, runs the QSWAT+ / SWAT+ Editor workflow, and exports a reviewable SWAT+ workspace (TxtInOut + GIS + SQLite). Open the package in SWAT+ Editor for scenarios; add calibration and validation with local data where your study requires it.
Related on SWATGenX
National datasets (labels)
This sample build uses the same CONUS resolutions as every SWATGenX package—NHDPlus HR at 1:24k, 30 m terrain (from 10 m 3DEP), 250 m NLCD/CDL (from 30 m), 250 m gSSURGO (from 10 m), ~4 km PRISM, and daily NSRDB at PRISM stations (from ~2 km, 30-minute data). See SWAT+ by state for the full stack. Methodology & provenance.
Citations for on-page facts
- Hydrologic catalog: USGS WBD — USGS station 03345000 (HUC12-located SWAT+ model)
- Hydrography: USGS NHDPlus HR — SWAT+ ``SWAT_plus_streams.shp`` ``NHDPlusID`` joined to HU4 ``NHDFlowline`` (FType/FCode); lengths summed in EPSG:5070 for the distribution table.
- Land cover (CDL): USDA NASS Cropland Data Layer (clipped to basin)
- Climate forcing: PRISM Climate Group (OSU), daily met files referenced in weather-sta.cli
- Regional population context: USGS governmental units overlay — county totals (sum within county, then across counties; avoids double-count from overlapping polygons).
SWAT+ in Illinois — common questions
- How do I run SWAT+ in Illinois? Use SWATGenX to screen basins in Illinois on the Watershed Explorer map, then queue a SWAT+ model build for a USGS gage, catalog HUC12, or HUC8. The platform assembles national datasets into a SWAT+ Editor package without manual QSWAT+ desktop prep for each basin. The sample model on this page is Embarras (USGS 03345000).
- What is the difference between SWAT and SWAT+ in Illinois? SWAT (legacy) and SWAT+ (current process-based watershed model) both support long-term hydrology and water-quality studies in Illinois. SWATGenX targets SWAT+ and delivers reproducible, high-resolution projects on NHDPlus HR hydrography.
- Can SWATGenX build SWAT+ models for Illinois watersheds? Yes. SWATGenX covers CONUS, including Illinois, with the same national data stack (WBD, NHDPlus HR, PRISM, NLCD, gSSURGO). Each state page documents a sample basin snapshot from a real SWATGenX build; open the live map at https://www.swatgenx.com/watershed-workspace to model your own watershed.
- Is SWAT+ modeling in Illinois free on SWATGenX? Signed-in users can explore Illinois on the map and use tiered quotas for reports and model builds. See https://www.swatgenx.com/pricing for Basic vs Pro limits; Pro adds optional cloud calibration where enabled.
Open Embarras in Watershed Explorer
Preview uses the USGS WBD boundary with NHDPlus HR context, zoomed to basin extent on a Streets-style basemap. Follow the card into the live workspace (HUC8 05120112).
