# Presentation: 665453

## NWSRFS users group workshop 2003

**NWSRFS users group workshop 2003**

**Estelle van Niekerk**
**Joyce Mathole**
** ****Department Water Affairs and Forestry, Republic of South Africa**

## Contents

**Background of the RSA **
**The RSA NWSRFS**
**Development of the RSA NWSRFS**
**Hydro-meteorological data collection**
**Data flow in the RSA NWSRFS**
**Problems experienced in implementation and calibration**
**Key organisations involved in the establishment of the RSA NWSRFS**
**The way forward**

## Position of the Republic of South Africa

**Southern tip of Africa**
**Roughly twice size of Texas**
**Population: 43 million**
**Rich in natural resources: (platinum, gold, chromium, antimony, coal, diamonds, etc.)**
**Sport: Rugby, Cricket, soccer, Athletics, golf, etc.**

## Slide 4

## Background

**Average rainfall 450mm/year (world average 860mm)**
**Poor spatial distribution of rainfall**
**Total run-off 49 200 x 10****6****m****3****/year**
**Capacity of large storage dams is approximately 30 000 x 10****6****m****3**
**Limited ground water potential**

## Slide 6

## RSA:Mean Annual Evaporation

## Slide 8

## Slide 9

## Slide 10

## Slide 11

## Slide 12

## Slide 13

## Hydro-meteorological Data Collection	

**Hydro-meteorological Data Collection****	**

**Flow data from gauging stations – real time at 52 stations in the Vaal/Orange and 210 country-wide**
**Rainfall – real time and daily**

## Slide 15

## Slide 16

## History of the RSA NWSRFS

**1996 initiated by a USA delegation from NWS during a visit to the RSA**
**Decision taken to implement the USA NWSRFS in the Vaal /Orange River system**
**Previously RSA flood forecasting system comprised only a flood routing model**

## History of the RSA NWSRFS (continued)

**Great enhancement to supplement our previous flood forecasting method**
**1999 RSA NWSRFS set up for 12 segments each with only of a (Muskingum) flood routing routine**
**2000 Riverside Technology inc (RTI) got involved and by 2003 the RSA NWSRFS was expanded to 47 segments each with a rainfall/runoff-model (Sacramento) and a routing model (Muskingum)**

## Key organisations in the establishment of the RSA NWSRFS

**RSA:**
**Department of Water Affairs and Forestry (DWAF) **
**South African Weather Services (SAWS)**
**Water Research Commission (WRC)**
**USA**
**NWS**
**US AID**
**Public Affairs Section of the USA Embassy**

## Problems with current RSA NWSRFS

**Calibration**
- Rain depth – inconsistencies between radar and point-rainfall
- Calibration of Sacramento-Soil Moisture Accounting model – Insufficient input of land and water-use data:
- Farm dams (total capacity of 150 x 106 m3  in Vaaldam catchment alone)
- Urban run-off increases
- Return flow
- Water transfer schemes
- Transmission losses
**Spatial and temporal distribution of real-time flow and rainfall data should be expanded to cover whole of RSA**
**Improved weather forecasts – ongoing research**

## The way forward

**The way forward**

** ****Priority to improve data input (e.g. spatial rainfall data)**
** ****Improved Sacramento model calibration through dedicated help**
**Expand our current RSA NWSRFS**
** ****Capacity building **