WATEX: A n e w a p p r o a c h t o p r e v e n t i n g w a t e r b a s e d c o n f l i c t s

Introduction the identification of four major campsites Since October 2006, the NGOs led by Dr Alain Gachet is the CEO of Radar In March 2004, the UN Office for the Co- able to host some 200,000 new . It UNICEF have achieved a success rate of 100 Technologies, France. As a radar expert he has ordination of Humanitarian Affairs (UNO- also led to the transfer of the first group of per cent in drilling 300 wells, whenever ap- advised a number of international bodies, such CHA) faced a severe challenge in providing 15,000 refugees to the newly identified Gaga plying the drilling handbook recommenda- as UNESCO, the UN, UNICEF and the OECD. assistance to 110,000 refugees from in Campsite, 65 km east of Abéché and to the tions on identified sites: He spent 20 years in the oil industry working , which grew to 200,000 a few months increase of drilling success rate from 33 per as a Senior Explorationist and Economist later. cent before WATEX© to 89 per cent using the • at the camps of North near negociator in Russia, Kazakhstan, the Middle WATEX© methodology. El Fasher: Abu Shouk, Shagra, Mellit; East and Africa. Currently he is involved The United Nations High Commissioner • around the camps of in remote sensing interpretation and the for Refugees (UNHCR) requested urgently the In December 2005, the US State Depart- near Nyala and Kas; and exploration of natural resources (groundwater, services of Radar Technologies France (RTF) ment invited me to apply the WATEX© proc- • around the camps of : base metals, minerals and hydrocarbons) to use the WATEX© process in order to de- ess throughout Darfur in Sudan, over an area El Geneina, Riyad, Ardamata, Murnei, and for the monitoring surveillance and tect and map the water potential of Eastern of 135,000 km2, for 2.5 million internally Zalingei, Dereisa, Nyertete and Foto environment. Ouaddaï in Chad to support existing camps, displaced persons (IDPs), under the supervi- Burunga. identify new buried aquifers and support sion of Dr Saud Amer from the US Geologi- future camps throughout the region cal Survey (USGS).3 How does WATEX© work? and avoid costly water trucking. This paper describes how the geospatial This project, accomplished in six months, WATEX© process was utilised by RTF to as- In just four months, RTF recorded amazing revealed that there is enough groundwater in sess the water potential of Eastern Chad and results applying the WATEX©-based method- Darfur for several million people — enough Darfur in Sudan without requiring time- ology1 to map the water potential of a region to sustain the peace process and the recon- consuming field surveys on ground cali- nearly 100,000 km2 in size. The humanitarian struction through agricultural development.4 brations for the remote sensing portion of dimension of the project demanded timely These results were forwarded at the request the project. Field surveys in Sudan were and efficient identification of sustainable aq- of the US Agency for International Develop- completed with ground penetrating radar uifers producing sufficient volumes of clean ment (USAID) to 40 NGOs in October 2006 equipment. water to support existing and future refugee in . The Darfur Drilling Handbook,5 operations. based on WATEX© results, was distributed to As demonstrated in Chad with the case all the organisations attending the training study of Gaga Camp, the project enabled This RTF operation in 2004-2005 in east- seminar supported by USAID and UNESCO the UNHCR to, in a very short time, identify ern Chad led in the following months2 to (Chair in Water Resources, Sudan). new campsites in eastern Chad capable of

1 Dr Alain Gachet (July 2004). Chad—Phase I—Water Exploration in Eastern Ouaddaï—Ground Survey. Edited by Geneva. Radar Technologies France: UNHCR. 2 Dr Alain Gachet (2005). Tchad—Phase II—Synthèse des études hydro géologiques par télédetection radar du Ouaddaï Oriental. Edited by Geneva. Radar Technologies France: UNHCR, pp. 52-4, 83. 3 Dr Saud Amer PhD, ‘Water Resources and Remote Sensing Specialist’, International Water Resources Branch, USGS, 12201 Sunrise Valley Drive, MS 420, Reston, VA, 20192, USA. 4 Dr Alain Gachet (2006). Water exploration in Darfur—Sudan Edited for USGS, UCSB and USAID, 30 May 2006 (89 pp.) 5 Dr Alain Gachet (2006). Darfur Drilling Handbook in Sudan Edited for USGS, UCSB and USAID, 30 May 2006 (123 pp.)

[ 311 ] supporting tens of thousands of Sudanese gional geological phenomena. Basic analysis 2. The 2003 release of the Shuttle Radar Top- refugees. confirmed that the ‘Basement Complex’ of ographic Mission (SRTM) global terrain Darfur degrades groundwater storage poten- model, which provides slope and elevation In Sudan, the study has, in six months, tial, except within alluvial sediments, which data of unprecedented quality compared revealed vast stretches of land in central are unfortunately prone to rapid evapo- with other topographic information of the Darfur hosting enough groundwater reserves transpiration if not thick enough. Long- region. to sustain 33 million people year round with term programs to deliver water by tankers the Sphere Humanitarian Charter Standards to the refugee camps were not sustainable 3. The relaxing of the selective availability of 15 litres of water per day. because of long distances and unreliable of global positioning system (GPS) signals, tracks, lack of security and deficient bridge enabling civilian access to precise location The study has also identified 27 micro- infrastructure. information almost anywhere on the sur- dam sites suitable for aquifers sustainability face of the earth. and agriculture. These aquifers are renewable Recognising the severity of these chal- and easily accessible within a depth ranging lenges and the inadequacy of utilising tra- 4. The widely appreciated ‘digital revolu- from sub-surface to 50 m in unconsolidated ditional water exploration drilling methods tion’, which is now affordable even to sediments, which are easy to drill. and in order to meet the above challenges, small firms without access to high-pow- UNHCR and USAID decided to employ RTF’s ered computing, user-friendly analysis Challenge and opportunity WATEX© proprietary remote sensing tech- software and rich data archives accessi- The response agencies needed to main- nology. It guided water drilling operations ble via the internet. tain operations over a region of 300,000 and optimised the location of refugee camps km2. Not only was this region undeveloped in minimum time. The WATEX© process and largely inaccessible, it was also within a UNHCR, together with USAID, recognised zone of conflict that affected the security of It was developed by RTF to support water an opportunity to apply geospatial technolo- both refugees and humanitarian relief work- exploration in arid and semi-arid areas and gies in responding to the Darfur crisis, creat- ers. Facing a refugee population that quickly exploits the increasing data stream from ing an excellent example of the positive role approached 200,000 in Chad and 2.5 million civilian geospatial technologies to analyse the private sector can play in humanitarian IDPs in Sudan, the authorities needed to dis- large, heterogeneous climatic and geologic assistance and sustainable development. cover, develop and deliver massive water re- regions for water potential. serves able to sustain water distribution for The WATEX© process is a groundwater several years without depleting the natural Several recent trends have made the use exploration package used to locate renew- resources of local communities. of such technology possible: able groundwater reserves in arid and semi- arid environments. This process dramati- This challenge was further complicated 1. The availability of synthetic aperture radar cally improves the ability of humanitarian by the extreme urgency imposed by the es- (SAR) earth observation satellite imagery, and development organisations to identify calation of the , the limited which provides highly sensitive geological areas suitable for (temporary and perma- resources with which to assess hydrological and hydrological intelligence not discern- nent) settlement, agriculture and sustainable potential and the poor understanding of re- able through optical imagery. development.

[ 312 ] The process is economical, rapid and Process well established,6 and known to be optimal highly effective for water and soils poten- The radar and optic data acquired by sat- in fine, dry sand with minimum volumetric tial mapping even over heterogeneous areas ellite are processed to achieve the project’s water content. However, even under ideal several hundred thousand square kilometres overarching goal — to detect large renewable conditions, the penetration of microwave in size. water reserves capable of supporting refugee signals is restricted to near-surface moisture settlements of 20,000 per camp, for up to detection, and therefore RTF focused upon 200,000 Sudanese refugees, in accordance the assessment of alluvial water potential with the UNHCR’s target provision rate of along existing wadis and nearby fractures 15 litres per day per person. This automati- and faults. (Deeper reservoirs can still be cally precluded water exploration of small detectable if capillary moisture flow or satu- or non-renewable reserves, and limited anal- rated zone reaches near-surface strata). ysis to areas of sizeable, renewable water potential. Large-scale groundwater reserve assessment General mapping After the region of interest had been suf- After interpreting Landsat 7 to determine ficiently mapped, RTF began an assessment Figure 1: Location diagrams lithology, weathering processes, vegetation of the following five key hydrologic param- cover, agriculture, settlements, roads/tracks, eters in order to establish an overall rank of the SRTM model was used to delineate wa- each ‘water potential anomaly’: tersheds, slopes and river profiles, and to es- timate energy level of transportation along 1. Dimension of the radar anomaly, which is wadi (i.e. riverbed) courses. an indicator of the potential of a buried aquifer within a wadi. As previously in- Radar images were processed using dicated, an aquifer with a renewable ca- WATEX© to map fractures, uplifts and sub- pability to produce 90,000 m3 per year is sidence, which control river direction and able to support a camp of 20,000 refu- affect groundwater circulation, aquifer thick- gees. Assuming an average rock porosity ness and storage by reservoir accretion or of 10 per cent, this implies the need to find erosion. a buried aquifer with an overall produc- tion of nearly 1 million m3 per year. This is WATEX© was also applied to enhance the equivalent to a wadi reservoir of about 2 km soil volumetric moisture effects of near-sur- long and 60 m wide, assuming a reservoir face stratum. The penetration and soil mois- thickness of 7.5 m at an average depth of ture sensitivity of SAR imagery has been 10-15 m. Accordingly, only radar anomalies

6 T. Ulaby, R. K. Moore and A. K. Fung, Microwave Remote Sensing: Active and passive. Dedham, MA: Artech House, 1986, vol. 3, From Theory to Applications.

[ 313 ] tween 0.1 and 0.4 per cent, in order to ensure sufficient vertical recharge of res- ervoirs within wadi courses. Too shallow a slope, and the reservoir can be prone to excessive silt accumulation, compromising its ability to store sufficient water reserves. Too steep a slope, and the reservoir can be prone to the erosion of the gravel bed that must recharge during the rainy season.

Figure 2: Radar backscattering anomaly revealed by WATEX©, Overall suitability assessment indicating existence of buried aquifer within the wadi course (© RTF 2004) The completion of steps 1-5 allows RTF to identify areas of high water potential. In or- covering a minimum surface of 12 hectares the aquifer determine its ability to reliably der for these areas to be suitable for refugee (2 km x 60 m) were considered by RTF in absorb and store sufficient water volumes. inhabitation, RTF also considered the impli- order to meet the above project goal. At WATEX© discriminates between ‘reservoir cations of refugee resettlement near areas this stage, it is not possible to know if the feeders’ and ‘reservoir poisoners’. For ex- of existing cattle ranching, crop farming, anomaly is due to a buried aquifer or sur- ample, basaltic rock types create excessive indigenous settlement, etc. In addition to face moisture linked to clay or silt deposits. silt and reduce reservoir porosity and per- UNHCR-mandated restrictions in Chad on More analysis of the short-listed anomalies meability. Alternatively, ‘reservoir feeders’ resettlement within 50 km of the Sudan bor- is required. such as quartzite and sandstone can pro- der or other areas of insecurity, RTF favoured duce high-quality gravels. potential camp locations that were close to 2. Amount of upstream watershed drain- roads and wood fuel sources. Reservoirs/aq- age, since each potentially suitable target 4. Major fault, since the ideal scenario is an uifers with high suitability were then exam- must also be fed by an upstream water- old, well-framed river bed with a reliable ined to ensure close proximity to a suitable shed capable of supplying at least 1 mil- and unchanging watercourse, downstream camp platform, located above the seasonal lion m3 per year of water to the reservoir. from a high-quality reservoir feeder. A flood plain. (This should be less than 500 m, (The watershed surface area and average reliable, linear river system controlled by as recommended by the SPHERE Humanitar- annual rainfall were used by RTF to esti- graben-like structures is more likely to con- ian Charter Minimum Water Standards).7 mate total yearly catchment, which was tain thick, multi-layered reservoirs, partic- then corrected for estimated losses due to ularly if it sits downstream from a source Development of drilling strategy evaporation, erratic run-off, etc.) of gravel or water-storing material. The final step in the project was to iden- tify drilling locations that were away from 3. Quality of aquifer gravels, since the origin 5. Slope of upstream wadi course, since the the central aquifer and towards the edge of and nature of the gravels which supply optimum riverbed slope needs to be be- the containment fracture. The construction

7 The Sphere Project Humanitarian Charter and Minimum Standards in Disaster Response Handbook (Revised Edition), Chapter 2. Geneva. From www.sphereproject.org, last accessed 15 July 2005.

[ 314 ] of well platforms directly in the path of peak The Wadi Dalal settlement of Gaga Camp gee camp, RTF estimated that at least 20,000 wadi flow can be catastrophic. By consider- is about 65 km east of Abéché, and was rec- people could be situated on a platform adja- ing the fault structure immediately adjacent ommend by RTF because of its exceptional cent to the potential aquifer, based on esti- to an aquifer but away from the wadi chan- combination of hydrogeologic characteristics mated water reserves. In May 2005 UNHCR nel, well damage from flood-induced erosion respecting the aforementioned five key hy- announced that the site had the capacity to can be prevented. drologic parameters. shelter up to 30,000 refugees to the area.

Results In February 2005, prior to UNHCR’s deci- The project demonstrated that the WA- sion to begin construction of the new refu- TEX© process, merging geospatial analysis with geological and hydrological exploration methods, was capable of improving signifi- Application of the five hydrologic parameters cantly the ability to predict water potential 1. Size of the radar anomaly: Medium to high amplitude, very big size, indicates with limited need for costly, time-consuming important aquifer. field survey. 2. Amount of upstream watershed drainage: an exceptionally high yield of 230 Results in Chad million m3/year minimum coming from the Azum watershed in Sudan (after Thanks to the existing database of approx- removing runoff and evaporation). imately 540 drilling sites throughout Ouadd- aï, it is possible to say that RTF’s WATEX© 3. Quality of the aquifer gravels: migmatites, granites, quartzites and schists process has improved drilling success rates provide high quality grains for the aquifers. Good conductivity is expected from from 33 per cent to nearly 90 per cent — re- future wells. sults based on a review of the water-drilling results of the Chad Hydrological Survey (and 4. Major faults: this system is well structured by old fractures: alluvial sequences various NGOs) through the years in the re- must be thick all along the Bahr Azum alluvial deposits (Lebotigue wells produce gion compared with more recent success us- more than 30 m3 per hour throughout the year from 9 to 45 m). ing WATEX©-derived data. 5. Slopes upstream wadi course: with an average of 0.689/100 m the slope is small Identification of but due to the water quantities flowing every year, the energy of transportation the new campsite of Gaga remains high enough to clear the silts, leading to a favourable vertical recharge. Key evidence of the efficiency of the WA- TEX© process is UNHCR’s decision to settle Conclusion: Bahr Azoum is most likely the most productive site of a major along the Wadi Dalal, Eastern Ouaddaï, with sustainable reserves and soils to feed several based on the analysis provided by RTF.8 hundred thousand people.

8 Gachet (2005), op. cit., see p. 83 on Wadi Dalal.

[ 315 ] Sustainable development potential on the Bahr Azum alluvial aquifer The Bahr Azum site, which is located 33 km south of Goz Beida in the Dar Syla prov- ince south of Eastern Ouaddaï in Chad, is fed upstream by the Azum watershed in Sudan, which drains 230 million m3 per year flowing along 100,000 hectares of alluvial terraces (red colours on Figure 5).

This is the most prolific site of Eastern Ouaddaï. It offers a unique combination of groundwater potential and soils which can be the base of the future reconstruction of the economy of Eastern Chad for the benefit Figure 3: Block diagram illustrates that radar imagery does not penetrate of the local population and for the refugees deeper than 18-20 m and that the WATEX© process deals exclusively from Sudan. with near sub-surface aquifers Results in Darfur—Sudan During the US National Groundwater As- sociation symposium in Albuquerque, New Mexico, USA, in May 2007, the results of the WATEX© study in Darfur were presented by Dr Saud Amer PhD and Dr Verne Schneider PhD, from the USGS in the ‘Remote Sens- ing Technique in Groundwater Exploration in Developing Countries’ seminar:9

Identification of aquifer potential in Cen- tral Darfur over an area of 135,000 km2 has been achieved by Radar Technologies France, USGS, UCSB and UNESCO in six months.

9 Dr Alain Gachet, Radar Technology France, Dr Saud Amer, and Dr Verne Schneider, US Geological Survey — National Figure 4: WATEX© image showing three successful exploration wells drilled in March Groundwater Association Summit: Remote Sensing Technique in Groundwater Exploration in Sudan, 2005 by UNHCR’s drilling contractor (OXFAM), which confirmed RTF’s expectation Wednesday, 2 May 2007.

[ 316 ] Potential water drilling site maps and drilling manuals have been produced and transferred to 40 NGOs operating in Dar- fur, under the supervision of UNESCO and UNICEF. Since October 2006, some 300 wells have been drilled thanks to UNICEF with 100 per cent success under the recommendations of RTF’s Darfur Drilling Handbook near the camps of:

• near El Fasher: IDP camps of Abu Shouk, Shagra and Mellit; • South Darfur around IDP camps of Nyala and Kas; and • West Darfur near El Geneina, on the IDP camps of Riyad, Kereinik, Um Tagouk, Ar- damata, and near the camps of Murnei, Figure 5: Interpreted WATEX© image of the Bahr Azum alluvial system flowing from Sudan Zalingei, Dereisa, Habilah, Ararah, Nyertete and Foto Burunga.

The study was funded by USAID-OFDA groundwater reserves to sustain 33 million The most important yields of 30 m3 per over an area hosting 2.5 million people, people year round with 15 litres of water hour have been recorded within shallow bur- where security is a major concern. per day. ied aquifers around 30 m deep and the drill- ing efficiency expressed in cubic metres per Such identification was made possible us- These aquifers are sustainable and easily metres drilled is 20 times higher inside the ing the WATEX© process based on new radar accessible within a depth ranging from sub- recommended WATEX©-mapped areas than remote sensing technologies developed and surface to 50 m in unconsolidated sediments, outside. patented by RTF. which are easy to drill. An important drilling success was recorded This process combined with optical remote Ground Penetrating Radar (GPR) was op- at greater depths down to 200 m for the UN sensing, geology, geomorphologic features erated by RTF over some calibration points, peacekeeping forces on Shagra wells, in the and climatic data, revealed over 200,000 confirming the depth and structure of aqui- Nubian sandstones West of El Fasher, as rec- km2 of buried aquifers not visible from the fers down to 40 m deep. Drilling results col- ommended in the Darfur Drilling Handbook. surface. lected in Sudan have confirmed the validity of the results with a success rate of 95 per All these results have been monitored and The study has also revealed vast stretches cent on 740 wells and boreholes. validated by UNESCO (CWR) in Khartoum- of land in hosting enough Sudan.

[ 317 ] Conclusions WATEX© is an innovative, holistic approach to hydrology, involving a fusion of geological North CHAD SUDAN Darfur exploration science and geospatial analysis that would not have been possible even just a few years ago and with very limited ground verification only 10 months ago. It has signifi- cantly increased the drilling success rate from 33 per cent to more than 95 per cent on new sustainable aquifers which have been discov- ered after scanning vast stretches of land (over 300,000 km2) between Chad and Sudan. West Darfur There is always, of course, some level of exploration risk, but in conditions of humani- tarian urgency, timely response, scarce re- South sources, security concerns, and inaccessible Darfur and massive areas of interest, this system has demonstrated the ability to identify suitable areas for resettlement and meet international Figure 6: The Groundwater Target Map of Darfur — June 2006. standards for water access. The most prolific alluvial systems are coded in red In Chad, key evidence of the efficiency of Figure 7: Dr Alain Gachet the WATEX© process is UNHCR’s decision to leading a Ground Penetrating settle a new refugee campsite of Gaga, based Team in Sudan. October 2006 on the analysis provided by RTF. UNHCR an- nounced in May 2005 that this site had the capacity to shelter up to 30,000 refugees.

RTF’s identification of the most prolific site along the Bahr Azum watershed in East- ern Ouaddaï, with a unique combination of groundwater and soils, offers the base of fu- ture reconstruction of Eastern Chad for the benefit of the local population and for the refugees of Sudan.

[ 318 ] In Sudan, the WATEX© process revealed in RTF joins many others in expressing deep June 2006 that there is enough groundwater thanks to NASA and the USGS for facilitat- in Darfur for several million people, enough ing collection, processing and distribution to sustain the peace process and reconstruc- of the SRTM mission data, which provided tion through agricultural development.10 crucial topographic intelligence ingested by the WATEX© hydrologic model. Future projects include micro-dam con- struction to increase aquifer replenishments, Similar appreciation is extended to the soil identification and qualifications, irri- governments of Chad, Japan and the United gation planning and mineral exploration. States for providing the aforementioned data This is symbiotic with the methodology em- used in the project. ployed, emphasizing the provision of a sound water resource management plan in order to Finally, RTF wishes to recognise the vision avoid groundwater resource unsustainability, and courageous support of Dr Saud Amer which could lead to a bigger crisis. and Dr Verne Schneider from the USGS (Re- ston, Virginia), Suzain Tokar from USAID, Acknowledgements and Dr John Harrald11 and Dr Firoz Verjee12 The author expresses his deep gratitude from ICDRM-GWU. to UNHCR for funding the Chad project in 2004-2005 and to USAID/OFDA for funding the Sudan project in 2006.

10 Dr Alain Gachet (2006). Water exploration in Darfur—Sudan. Edited for USGS, UCSB and USAID, 30 May 2006 (89 pp.) 11 Dr John Harrald, Director, Institute for Crisis, Disaster and Risk Management and Professor of Engineering Management, The George Washington University (see [email protected]) 12 Dr Firoz Verjee, DSc, Research Associate Institute for Crisis, Disaster and Risk Management, School of Engineering and Applied Science, The Georges Washington University, 1776 G. Street, NW, Room 109, Washington, D.C. 20052.

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