NILE RIVER FLOOD PROTECTION

Prof. Medhat Aziz Director, NRI, MWRI,EGYPT Eng. Tahani Sileet General Director, Nile Water Sector, MWRI,EGYPT

Basin area : about 3.0 million square km.

Area of lakes is 81,500 square km.

Area of swamps is 70,000 square km.

Length : 6700 km.

Length of Rivers and Tributaries is 37,500 km.

Average annual rainfall 1661 BCM

Average annual yield at Aswan 84 BCM

11 Riparian States with 370 million people

Main Features of the Nile River

Nile River Flood Classification

• Highest recorded flood for the natural river at Aswan :150 BCM(1878-1879)

• Lowest recorded value: 42 BCM(1913-1914).

• Nile River natural flow records at Aswan can be divided into 5 categories: 1-Very low flood (52, or less, BCM). 2-Low flood (70 BCM). 3-Average flood (92 BCM). 4-High flood (110 BCM). 5-Very high flood (exceeding 110 billion BCM).

Key Issues in Flood Management

Lack of good quality hydrological (flow) data Establishing and operating real time gauging

stations Data Communication system & data sharing

between agencies & countries Lack of capacity to predict short period rainfall

data Institution and Staff capacity building in flood

forecasting & hydrological models Sustainability of flood forecasting systems Very short lead time

Regional Background Sudan

• The annual flood from the Blue Nile replenishes soil moisture and fertility, and

recharges groundwater, so is the mainstay of agriculture • Hundreds of villages ,because of their proximity to the river banks are

adversely affected in years of above average floods. Egypt

• HAD was completed in 1970, and generation of hydropower and regulation

of water for irrigation became a mainstay of the Egyptian economy. • Storage filled over about 10 years, and releases were stable until Ethiopia

severe droughts in the 1980s, where the lake levels declined progressively • High flood years in 1998 to 2001 proved that flood risk management is still on

the agenda for the government of Egypt.

Sinai Flash Floods • Flash floods on and after 18 January 2010 left 780

homes totally destroyed, 1,076 submerged and the area suffered material losses of over US$25.3 million.

• The floods ruined 59km of roads, killed 1,838 animals and felled 27,820 (mostly olive) trees.

August 2013. Khartoum, Sudan Photo: IFRC

Examples of flood Damage Impact of Flash Floods as of 11 August 2014 in

Sudan Source IRCS . (IFRC)

Measures Undertaken Egypt

• High flood risk: o Nile River bank protection (about 200 km along the River Nile were protected by

stone revetment). o Hydraulic structure protection o Prevention of Nile encroachments to allow for the river maximum discharge

capacity.

• Low flood risk: o Providing water requirements for agricultural lands o Solving navigation problems

Sudan • Some riparian villages have developed systems of low

levees (terraces) .

• More formal levees exist in certain urban areas (Khartoum, Dongola) .

Flood Forecasting Egypt

• Nile Water Sector: watershed rainfall monitoring using rainfall satellite images, which

give an indication for the coming flood for about ten days in advance. the sector monitors the flood water levels and discharges along Nile Basin gauging stations.

• Planning Sector: monitors, through flood forecasting and simulation center, the climatic changes and Nile Basin rainfall indications. It uses the satellite images and hydrological models.

• HAD Authority : Uses the previous flow records and compare it with the coming flood records using the least square method to develop a linear relationship between incoming flow from the beginning of August to the end of June and the forecasting flood period. The authority uses the previous Nile Basin flood records to get an approximation for the coming flood. For short periods, the coming flow records are used to have an indication for the coming 15 days.

• Nile Research Institute: uses the statistical forecasting approaches performing historical record analysis to propose and outline the target flow. It can provide the forecasting for one or more coming year/s.

Flood Foecasting Egypt

0

50

100

150

200

250

1 12 23 34 45 56 67 78 89 100

111

122

133

144

155

166

177

188

199

210

221

232

243

254

265

276

287

298

309

320

331

342

353

364

Billi

on C

ubic

Met

er

Day

2013/14 Average from 2001/02 to 2012/13

0

50

100

150

200

250

300

1 12 23 34 45 56 67 78 89 100

111

122

133

144

155

166

177

188

199

210

221

232

243

254

265

276

287

298

309

320

331

342

353

364

Billi

on C

ubic

Met

er

Day

2001/02 2002/03 2003/04 2004/05 2004/05 2005/06 2006/07

2007/08 2008/09 2009/10 2010/11 2011/12 2012/13 2013/14

0

5

10

15

20

25

Apr

il

May

June

July

Aug Se

p

Oct

Nov Dec Jan

Feb

Mar

ch

Billi

on C

ubic

Met

er

Average 2013/2014

Data : Rainfall Satellite Images RFE (8km) 3products: Accumulated rainfall for studied year compared with : accumulated of the pervious years, average accumulated rainfall for the pervious years and Every 10 days for studied year compared with average for each 10 days for pervious years.

Nile Forecast Center • established in 1992 to provide a real-time hydro-

meteorological forecasting system for the Nile River Basin.

• Capabilities: - Monitor hydro meteorological conditions in the Blue

Nile and Atbara Basins; - Data management and processing; - Analyze outputs from different forecasting tools - Produce and distribute regular Nile Forecast Center

Bulletin - Set different alternatives and scenarios for Nile WRM

Flood Forecasting Sudan

• Following the floods of 1988, the Sudanese Ministry of Irrigation and Water Resources initiated the establishing of an operational flood forecasting system, developed with the Netherland technical assistance and became operational in 1992, known as FEWS Sudan.

• This system was updated in collaboration with ENTRO with the modern standards of the current Delft FEWS forecasting platform using data provided from Different sources : Rainfall estimates(USGS, TRMM and CMORPH) and water level from Hydrological stations.

•

Flood Forecasting Sudan

The forecasting model is combined from three models: o HEC-HMS rainfall runoff model of the upper blue Nile catchement (upstream of the

border at Eddeim gauging station). o HEC-RAS model of the Blue Nile between Eddeim and Khartoum o Linear correlation Models between key gauges in the Blue and Main Nile between

Eddeim and Dongola.

Major output of the Sudan FEWS : o Estimated rainfall gridded maps and weighed rainfall hyetographs o Simulated flow hydrograph at Eddeim (upper Blue Nile watershed outlet) using HEC-HMS

hydrological model based on satellite rainfall estimates. o Updated forecast flow hydrograph at Eddeim based on the observed flow series during

the historical period. o Simulated and updated forecast of flow and water level hydrographs at Blue Nile Hydro

stations: Roseires, Singa, Sennar, Medani, Kamlin, and Khartoum. o Flood season comparisons for the observed 2014 flood water level hydrograph with the

historical water level hydrographs and seasonal mean. o Linear correlation water level forecast at Blue and main Nile from Eddeim to Dongola.

•