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F. Fussi (1), L. Fumagalli (1), T. Bonomi (1), F. Fava (1), B. Di Mauro (1), C.H. Kane (2), M. Faye (3), S. Wade (3), G. Faye (3), B. Hamidou (4), R. Colombo.

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Presentation on theme: "F. Fussi (1), L. Fumagalli (1), T. Bonomi (1), F. Fava (1), B. Di Mauro (1), C.H. Kane (2), M. Faye (3), S. Wade (3), G. Faye (3), B. Hamidou (4), R. Colombo."— Presentation transcript:

1 F. Fussi (1), L. Fumagalli (1), T. Bonomi (1), F. Fava (1), B. Di Mauro (1), C.H. Kane (2), M. Faye (3), S. Wade (3), G. Faye (3), B. Hamidou (4), R. Colombo (1) (1)University Milano Bicocca, (2) University of Thies, (3) University Cheik Anta Diop – Dakar, (4) SNAPE - Conakry contact: fabio.fussi@usa.net Use of remote sensing and terrain modeling to identify suitable zones for manual drilling in Africa and support low cost water supply Groundwater, poverty and development, Overseas Development Institute, London 28/11/2014

2 STRUCTURE OF THE PRESENTATION  Introduction to manual drilling  Previous studies on suitable zones for manual drilling  The research project  General research approach  Hydrogeological data processing  Remote Sensing  Results achieved and next steps Groundwater, poverty and development, Overseas Development Institute, London 28/11/2014

3 Introduction to manual drilling MANUAL DRILLING techniques of drilling boreholes for groundwater exploitation using human or animal power (not mechanized equipment). These techniques are well known in countries with large alluvial deposits (India, Nepal, Bangladesh, etc) High quality hand drilled wells can provide sustainable and clean water supply Groundwater, poverty and development, Overseas Development Institute, London 28/11/2014 Introduction to Manual Drilling

4 Advantages and limitations Advantages of manual drilling  Cheaper than mechanized boreholes  Easy to implement with locally made equipment  “manual work intensive” and not “capital intensive” ; source of income for local groups Limitations of manual drilling Manual drilling is feasible only under hydrogeological suitable conditions  Soft unconsolidated shallow geological layers  Water level not too deep  Good hydraulic conductivity of shallow porous aquifers IT IS IMPORTANT TO IDENTIFY THOSE ZONES WHERE HYDROGEOLOGICAL CONDITIONS ARE SUITABLE FOR MANUAL DRILLING Introduction to Manual Drilling Groundwater, poverty and development, Overseas Development Institute, London 28/11/2014

5 Previous maps of suitable zones for manual drilling  BENIN  BURUNDI  CENTRAL AFRICAN REPUBLIC  CHAD  GUINEA  IVORY COAST  LIBERIA  MADAGASCAR  MALI  MAURITANIA  NIGER  SENEGAL  SIERRA LEONE  TOGO  ZAMBIA Since 2008 UNICEF has produced maps of suitable zones for manual drilling in 15 countries in Africa: Previous studies on suitable zones Groundwater, poverty and development, Overseas Development Institute, London 28/11/2014 http://www.unicef.org/wash/index_54332.html

6 Previous method to identify suitable conditions for manual drilling (UNICEF) Previous studies on suitable zones Data sources:  EXISTING MAPS  NATIONAL DATABASE OF WATER POINTS  QUALITATIVE EXPERIENCE OF WATER EXPERTS IN THE COUNTRY Limitations:  Input data are limited and often at very broad scale,  inadequate for reliable interpretation (where data are limited) and more detailed study  Not systematic and structured procedure for data analysis. Difficult to compare results from different countries Groundwater, poverty and development, Overseas Development Institute, London 28/11/2014 COMBINED ANALYSIS OF 3 PARAMETERS:

7 THE UPGRO RESEARCH PROJECT University Milano Bicocca (Italy) University Cheik Anta Diop (Senegal) SNAPE (Guinea) UNICEF (Guinea and Senegal) PARTNERS FUNDED BY: Groundwater, poverty and development, Overseas Development Institute, London 28/11/2014 Use of remote sensing and terrain modeling to identify suitable zones for manual drilling in Africa and support low cost water supply

8 Main goal of the research OBJECTIVE OF THE RESEARCH Integration of direct hydrogeological information from existing database with indirect parameters from Remote Sensing and terrain modeling to characterize shallow aquifers and identify suitable zones for manual drilling DURATION November 2013 – April 2015 Groundwater, poverty and development, Overseas Development Institute, London 28/11/2014 The research project

9 Research study area REGION OF KANKAN AND FARANAH (EAST GUINEA) REGION OF LOUGA – KEBEMER (NORTH WEST SENEGAL Groundwater, poverty and development, Overseas Development Institute, London 28/11/2014 The research project

10 Scientific approach Geo-Environmental indicators (Geology, Soil, Morphometry, Vegetation dynamics, Soil moisture, Thermal Inertia) Thematic maps, Remote Sensing (optical, radar), Digital terrain model (Geo)Statistical model Borehole logs interpretation, pump test, geophysics Map of suitable zones for manual drilling Hydrogeological features at observation points Groundwater, poverty and development, Overseas Development Institute, London 28/11/2014 General research approach

11 Methodological approach Geology, Sols, etc Topography &Geomorp hology Vegetation Type & Persistence Thermal Inertia Soil Moisture Base maps STRM/AS TER DEM MODIS Veg. Ind. MODIS LST & ALBEDO RADAR ASAR P, K, T, suitability class (estimated) P, K, T, suitability class (estimated) Classification (e.g. CART) Borelogs - TANGAFRIC Training set (P, K, T, class) Testing set (P, K, T, class) P, K, T, suitability class (observed) P, K, T, suitability class (observed) Accuracy assessment (e.g. Q2, RMSE) cal val Spatial maps Groundwater, poverty and development, Overseas Development Institute, London 28/11/2014 General research approach

12 Definition of a 2 steps procedure to estimate suitability for manual drilling Groundwater, poverty and development, Overseas Development Institute, London 28/11/2014 Feasibility: It depends on -depth of hard rock - depth of water level - thickness of hard lateritic layers Potential for exploitation -It is obtained from assigning class of potential based on hydraulic transmissivity of porous unconsolidated aquifer from 0 to 50 m (considered the maximum epth for manual drilling) Estimation potential General research approach

13 Development of a specific software and codification of hydrogeological data CALIBRATION OF HYDRAULIC PARAMETERS THROUGH FIELD MEASUREMENTS Pump and recovery test in hand dug wells K = 4*10 -5 m/s DATABASE OF WATER POINTS SENEGAL AND GUINEA STANDARDIZATION OF DATABASE STRUCTURE IDENTIFICATION OF MOST FREQUENT CATEGORIES ASSIGNING STRATIGRAPHIC CODES Groundwater, poverty and development, Overseas Development Institute, London 28/11/2014 Hydrogeological data processing

14 Processing of stratigraphic data CALIBRATION OF HYDRAULIC PARAMETERS THROUGH FIELD MEASUREMENTS Pump and recovery test in hand dug wells K = 4*10 -5 m/s Groundwater, poverty and development, Overseas Development Institute, London 28/11/2014 DATABASE OF WATER POINTS AND CODIFIED STRATIGRAPHIC LOGS FOR SENEGAL AND GUINEA PROCESSING OF STRATIGRAPHIC AND PIEZOMETRIC DATA Hydrogeological data processing Bonomi, T., (2009): Database development and 3D modeling of textural variations in heterogeneous, unconsolidated aquifer media: Application to the Milan plain. Computers & Geosciences 35 (2009) 134–145 Processing of hydrogeological data have been based on previous experience in Italy (Bonomi, 2009) and adapted to the context of Senegal and Guinea

15 Processing of stratigraphic data Groundwater, poverty and development, Overseas Development Institute, London 28/11/2014 EXTRACTION OF: Each 2 m intervals:  TEXTURE  HYDRAULIC CONDUCTIVITY For the whole log:  DEPTH OF HARD ROCK,  DEPTH OF WATER TABLE  THICKNESS OF HARD LATERITIC LAYERS  HYDRAULIC CONDUCTIVITY (K) OF UNCONSOLIDATED LAYER  TRANSMISSIVITY EXTRACTION OF: Each 2 m intervals:  TEXTURE  HYDRAULIC CONDUCTIVITY For the whole log:  DEPTH OF HARD ROCK,  DEPTH OF WATER TABLE  THICKNESS OF HARD LATERITIC LAYERS  HYDRAULIC CONDUCTIVITY (K) OF UNCONSOLIDATED LAYER  TRANSMISSIVITY Processing of textural data at intervals of 2 m (Tangram software) Hydrogeological data processing

16 Extraction of hydrogeological parameters at borehole logs position Groundwater, poverty and development, Overseas Development Institute, London 28/11/2014 Depth of water Depth of hard rock Thickness of laterite Average K (in exploitable layers) Hydrogeological data processing

17 Estimating feasibility and potential for manual drilling at logs position Groundwater, poverty and development, Overseas Development Institute, London 28/11/2014 Hydrogeological data processing SENEGAL STUDY AREA

18 Multitemporal analysis of ATI  Thermal Inertia (TI) is related to the characteristics of the surface materials as well as surface water content.  Apparent Thermal Inertia (ATI) [K -1 ]can be estimated using solely remote sensing optical and thermal data (Van Doning et al., 2012 IJAEG). -α 0 is the albedo estimated from MODIS satellite optical data (MCD43B3 – 16 day – 1km) -A is the amplitude of the diurnal cycle of the land surface temperature estimated from day/night MODIS thermal observations (MOD11C1/MYD11C1 – daily (4 overpass/day) – 1km). -C is a solar correction factor. Van Doninck J., Peters J., De Baets B., De Clercq E.M., Ducheynec E., Verhoesta N.E.C. (2011). The potential of multitemporal Aqua and Terra MODIS apparent thermal inertia as a soil moisture indicator. Int. J. App. Earth Obs. Geoinf. 13, 934–941 Remote Sensing Groundwater, poverty and development, Overseas Development Institute, London 28/11/2014

19 Multitemporal analysis of ATI Daily time series of ATI (2012) MODIS DATA (1km) MOD11C1/MYD11C1 + MCD43B3 Data selection: no precipitation/clouds Dry season ATI map LOUGA 0.20.4 [K -1 ] Dry ATI map 2012 (1km) - Northern Senegal N 50 km Groundwater, poverty and development, 28/11/2014, Overseas Development Ini Remote Sensing

20 Vegetation Dynamics The abundance, type and seasonal variations of vegetation are dependent from nutrient and water availability. Especially in drylands, vegetation can thus be related to water availability across the landscape. Vegetation persistence or poor sensitivity from precipitation patterns may reflect the presence of shallow water and/or substrates suitable for deep plant roots development. Normalized Difference Vegetation Index (NDVI) time series were analysed to assess phenological indicators of vegetation cover and persistence during the dry season. 2007 2009 2010 2011 2012 2008 YEAR Remote Sensing Groundwater, poverty and development, Overseas Development Institute, London 28/11/2014

21 Vegetation Dynamics MOD13Q1 (TERRA/AQUA MODIS - 16 day - Vegetation Indices, 250 m) 2008-2012 Filtering and smoothing procedure Extraction of phenological metrics. Start of season, End of season, maximum, minimun, seasonal mean, etc Vegetation persistence indicators (5 years average) -Mean dry season NDVI -Rate of NDVI decreas -Dry season lenght LOUGA DRY SEASON LENGHT (Number of days) 200-220 220-240 240-260 260-280 280-300 LOUGA DRY SEASON MEAN NDVI 0.10.25 Remote Sensing Groundwater, poverty and development, Overseas Development Institute, London 28/11/2014

22 SOIL MOISTURE DYNAMICS Soil moisture dynamics may indicate areas with high water holding capacity or water accumulation. ENVISAT-ASAR radar data (Global mode -1km) between 2008 and 2012 in C-band are used to estimate soil moisture by inversion of the radiative transfer model proposed by Karam et al., 1992. Biomass maps derived from SPOT vegetation were used to separate the contribution of vegetation and soil moisture on the radar signal. Karam M.A., Fung A.K., Lang R.H. and Chauhan N.S., 1992 : Microwave scattering model for layered vegetation, IEEE Trans. Geosci. Remote Sens., 30:767-784. LOUGA SOIL MOISTURE (%) 0100 June 2010 Remote Sensing Groundwater, poverty and development, Overseas Development Institute, London 28/11/2014

23 Results achieved and next steps MAIN RESULTS ACHIEVED  Elaboration of a specific software to organize and process hydrogeological data based on the inventory of Senegal and Guinea  Definition of a structured method to estimate suitability for manual drilling  Production of maps of hydrogeological parameters and suitability for manual drilling at borehole logs positions in Senegal  Definition of procedures and generation of maps of soil moisture, phenology and ATI from optical and radar data  First set of direct field data (geophysics, pump test) collected and intepreted in Senegal NEXT STEPS  Completing field data collection in Senegal. And (depending from Ebola outbreak) in Guinea.  Validation of hydrogeological interpretation with field information  Definition of geostatistical model and integrated analysis of data  Spatialisation of hydrogeological interpretation from borehole logs position to the whole area  Generating maps of suitability for manual drilling Groundwater, poverty and development, Overseas Development Institute, London 28/11/2014

24 Thanks very much for the attention


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