The potential of satellite radar altimetry in flood forecasting: concept and implementation for the Niger-Benue river basin
Flood forecasting in the downstream part of any hydrological basin is extremely difficult due to the lack of basin-wide hydrological information in near real-time and the absence of a data-sharing treaty among the transboundary nations. The accuracy of forecasts emerging from a hydrological mode...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2015-06-01
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| Series: | Proceedings of the International Association of Hydrological Sciences |
| Online Access: | https://www.proc-iahs.net/370/223/2015/piahs-370-223-2015.pdf |
| Summary: | Flood forecasting in the downstream part of any hydrological basin is
extremely difficult due to the lack of basin-wide hydrological information
in near real-time and the absence of a data-sharing treaty among the
transboundary nations. The accuracy of forecasts emerging from a
hydrological model could be compromised without prior knowledge of the
day-to-day flow regulation at different locations upstream of the Niger and
Benue rivers. Only satellite altimeter monitoring allows us to identify the
actual river levels upstream that reflect the human intervention at that
location. This is critical for making accurate downstream forecasts. This
present study aims to demonstrate the capability of altimeter-based flood
forecasting along the Niger-Benue River in Nigeria. The study includes the
comparison of decadal (at every 10 days from Jason-2) or monthly (at every
35 days from Envisat/AltiKa) observations from 2002 to 2014, with historical
in situ measurements from 1990 to 2012. The water level obtained from these
sources shows a good correlation (0.7–0.9). After validation of hydrological
parameters obtained from two sources, a quantitative relation (rating curve)
of upstream water level and downstream discharge is derived. This relation
is then adopted for calculation of discharge at observation points, which is
used to propagate the flow downstream at a desired location using a
hydraulic river model. Results from this study from Jason-2 shows a
promising correlation (<i>R</i><sup>2</sup> ≥ 90% with a Nash-Sutcliffe
coefficient of more than 0.70) with 5~days ahead of downstream flow
prediction over the Benue stream. |
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| ISSN: | 2199-8981 2199-899X |