IWMIHQ/southern_africa_water_accounting

Southern Africa Water Accounting

Water accounting for southern Africa at ~1060 m: rainfall, total ET, green and blue ET, water yield and runoff, each as a yearly average and split into dry and wet seasons, averaged over 2003-2021. Water Accounting Plus output rebuilt from IWMI's Africa GeoPortal tile services, which serve no downloadable raster.

• Region Southern Africa
• Period 2003-2021
• Theme Water accounting
• Grid EPSG:4326, 3056 x 3196 at 0.009521932 deg (~1060 m)
• Bands 18
• Files 18 Cloud-Optimised GeoTIFFs under data/, named <band>.tif, one per band

Bands

Band	Type	Units	Nodata
yearly_rainfall	float32	mm	-9999.0
yearly_et	float32	mm	-9999.0
yearly_rainfall_et	float32	mm	-9999.0
yearly_incremental_et	float32	mm	-9999.0
yearly_water_yield	float32	mm	-9999.0
yearly_runoff	float32	mm	-9999.0
dry_rainfall	float32	mm	-9999.0
dry_et	float32	mm	-9999.0
dry_rainfall_et	float32	mm	-9999.0
dry_incremental_et	float32	mm	-9999.0
dry_water_yield	float32	mm	-9999.0
dry_runoff	float32	mm	-9999.0
wet_rainfall	float32	mm	-9999.0
wet_et	float32	mm	-9999.0
wet_rainfall_et	float32	mm	-9999.0
wet_incremental_et	float32	mm	-9999.0
wet_water_yield	float32	mm	-9999.0
wet_runoff	float32	mm	-9999.0

Read it

These are COGs, so GDAL reads them in place over HTTP -- no full download, and a windowed read fetches only the bytes it needs:

from huggingface_hub import hf_hub_url
import rasterio

url = hf_hub_url("IWMIHQ/southern_africa_water_accounting", "data/dry_et.tif", repo_type="dataset")
with rasterio.open(url) as src:
    print(src.width, src.height, src.crs, src.nodata)
    patch = src.read(1, window=((0, 256), (0, 256)))

Or pull the whole repo:

from huggingface_hub import snapshot_download
path = snapshot_download("IWMIHQ/southern_africa_water_accounting", repo_type="dataset")

Read this before using it

A 2003-2021 AVERAGE, not a time series. The period is the publisher's own: its sibling "Seasonal Maps" and "Yearly Maps" items for Southern Africa both carry 2003-2021 in their titles. Every cell is a multi-year mean, so no individual year is described and no trend can be read from it. Season months are undeclared. Nothing in the service metadata or the item records says where the dry season ends and the wet begins, so these bands cannot be aligned to a calendar or compared with another dataset's seasons. What is known is measured: the wet season averages 555 mm of rainfall against the dry season's 135 mm. The yearly bands are redundant rather than independent: dry + wet reproduces yearly to within 0.009018 mm, so agreement between them corroborates nothing. The exception is a scatter of individual bad cells: runoff breaks the sum in 1825 cells of 5700875, by up to 238 mm. Fewer than a hundredth of a percent, but mask aggressively if you difference the seasons against the yearly band. Dry-season water yield averages -77 mm, i.e. negative: ET exceeds rainfall and draws on stored moisture. Ordinary for a dry season, but it means that band is not "water available". Only 58.4% of the frame carries data -- the rest lies outside the mapped area -- so any whole-frame statistic is meaningless. Rebuilt from a tile cache rather than downloaded, so these values are whatever was published into the LERC pyramid, read at the pyramid level that matches the services' native resolution. The ArcGIS service named in each file's source tag remains the authority. The 18 source services do not report identical corner coordinates: they differ by up to 3e-06 degrees, about 333.96 mm on the ground -- 0.00032 of a pixel. The dataset declares the grid the majority agree on. Nothing is resampled; this is recorded only so the discrepancy is not rediscovered as a bug.

Provenance

Rebuilt from IWMI Africa GeoPortal ArcGIS image services, which serve no downloadable raster: they answer exportImage with HTTP 400 because their capabilities are Image,TilesOnly. The full-resolution grid was recovered by fetching every LERC tile at the pyramid level matching the service's own native resolution, decoding, and mosaicking. Each GeoTIFF carries the originating service in its source tag, and that service -- not this copy -- is the authority for its values.

The same product is indexed in IWMI's Open Data Cube, which is the route to its footprint, time extent and band metadata as STAC:

https://explorer-production-0070.up.railway.app/stac/collections/southern_africa_water_accounting

Citation

International Water Management Institute (IWMI), Southern Africa Water Accounting. Published via the IWMI Open Data Cube. Licence CC-BY-4.0.

@misc{iwmi_southern_africa_water_accounting,
  title        = {Southern Africa Water Accounting},
  author       = {International Water Management Institute},
  howpublished = {Hugging Face Hub, IWMIHQ/southern_africa_water_accounting},
  note         = {Derived from IWMI Africa GeoPortal services; see Provenance},
  year         = {2026}
}