Page 109 - CIWA Water Data Revolution Overview Report

Figure 1. The Scale Invariant Water Accounting Plus (SIWA+) framework. (Velpuri et al.,
2024).

3.0 Implementation of the SIWA+ Approach in the Volta, Incomati and Maputo basins

The first step in the implementation of the SIWA+ approach for water accounting assessment

involves the collection of remote sensing, geospatial and other data sets. These were
acquired from several sources, pre-processed, and reorganized into a consistent format for

input into the WA+ framework.

3.1 Summary input data for the Volta, Incomati and Maputo basins

In developing the water accounts for the Volta, Incomati and Maputo basins, a similar set of

dynamic and static data are used, providing a standardized approach to monitoring key water

resource metrics across regions. Dynamic inputs include data such as precipitation from
CHIRPS v2 product for the Volta basin while Incomati and Maputo used precipitation from

ARC v2. The selection of the ARC product was based on validation with available station data

and subsequent bias correction.

Actual ET, and reference ET, were drawn from SSEBop v5, and GLEAM v3.6a respectively for
all basins. Additional data like Leaf Area Index (LAI) and Net Primary Productivity (NPP) are

also used for all the basins. Static data sources, including soil moisture, digital elevation, and

landcover, were common across basins as well. All datasets cover the period from 2003 to

2021 for each basin. The remote sensing-based actual ET was only available from 2003, and
2021 was the last full year for which data was available when the generated discharge data

for the water accounting model was developed. However, with more recent data are now