An integrated approach to select and characterize benchmark watersheds for sustainable resources management in Libya

Transcription

1 FIRST INTERNATIONAL SUSTAINABLE WATERSHED MANAGEMENT CONFERENCE (SuWaMa) September 2011, Istanbul, Turkey An integrated approach to select and characterize benchmark watersheds for sustainable resources management in Libya Feras Ziadat1, Ahmed Al Wadaey1, Ahmed Al-Buaishe2, Theib Oweis1, Mohamed Elkhboli2, Jumah Fhima2 1 International Center for Agricultural Research in the Dry Areas (ICARDA), ICARDA 2 Agricultural Research Center (ARC) Libya

2 Introduction Water shortage is chronic in the arid regions with obvious impact on sustainable agricultural development Potential of Rainwater harvesting and supplemental irrigation to: Improve land and water productivity, Maintain productive and sustainable agro-pastoral systems, Control soil erosion, and, Mitigate the spatial and temporal variability of rainfall Sustainable implementation of these options become more urgent within the expected scenarios of climate change, where: Rainfall is expected to decrease, and, Extreme storm events is expected to increase

3 Introduction However, adoption of these interventions is low, due to: Lack of systematic knowledge on the selection of appropriate sites and suitable interventions for each biophysical and socio-economic setting Objectives: To develop and implement an integrated approach for the selection and characterization of benchmark watersheds (biophysical and socioeconomic aspects) To build a comprehensive database that is useful for integrated watershed monitoring, assessment and management

4 Research Approaches Watershed: Basic element of integrated natural resources management to enhance better management Benchmark research sites (watershed): Integrated research for development within watershed, Potential for Outscaling Modeling: Understanding the impact of improved interventions at field and watershed levels Participatory approach watershed as field laboratory

5 Benchmark Watershed Selection and Characterization Simplified Developing selection criteria Selection of benchmark watersheds Data collection within selected watersheds Data collection and processing Data analyses Field visit and meetings (inter-disciplinary team) Suitability analyses Hydrological assessment Socioeconomic characterization Tools to support decisions on sustainable watershed management Data integration and analyses Characterization of benchmark watersheds Implementation and monitoring of benchmark watersheds

6 Developing the selection criteria Criteria for each discipline (rainwater harvesting, rangeland, cropping systems, small ruminant productivity, Socio-economic) Integrated and modified (inter-disciplinary team) Circulated Finalized

7 Study areas agricultural regions mapping 2 study areas

8 Data collection and preparation expert criteria Study area and satellite image Precipitation interpolation from met. stations and FAO data Land Cover / Land Use (cropping systems) Communities and Roads (accessibility) Topography (slope percent) Watershed boundaries Soil

9 Apply the selection criteria - Precipitation Intersect watersheds with precipitation Calculate minimum and maximum rainfall for each watershed Apply the criterion 26 watersheds could be considered for further analyses Apply another criterion...

10 Apply the selection criteria - Presence of communities Overlay location of communities with watersheds Apply the criterion 5 watersheds were eliminated from the previous selection No community close to cropping systems Apply another criterion...

11 Apply the rest of the criteria Criteria Cropping systems Accessibility and visibility Topography Soil limitation(s) Data / Layers Land use / Land cover Road network Slope (DEM) Soil map Potential watersheds 16 watersheds visited by inter-disciplinary team in the Eastern study area

12 Inter-disciplinary team visiting the potential watersheds Range, Hydrologist, GIS, Crops, Livestock production, Soil, Land resource management, Agricultural economist, Agronomist, Water and Irrigation, Ground/surface water,

13 Post field visit Meetings and Election for watersheds Final selection - East West Three Four watersheds: Al Samalos Ghadama Saffeat Al-Qatara Al-Mualaq Al-Nakaza 17 Al-Marj

14 Benchmark Watersheds Characterization Selected watersheds (watershed selection process) East West

15 Description of the data collected Weather stations Rainfall (monthly average), Number of rainy days, Daily maximum rainfall, Minimum and maximum T, Wind speed, Relative humidity, Daily evaporation West East

16 Cropping (production) systems (land cover / land use) East West

17 Topography and slope data Slope steepness Contour lines and drainage system

18 Water resources and water harvesting structures - location Structure Number Deep wells 583 Armed Barrage 1258 Earth Barrage Romani wells 758 Storage dams 13 Obstruction dams (Gabion) 15 West East

19 Soil data (scale 1:50,000) Soil depth Soil salinity Soil ph Soil texture Calcium carbonates

20 Land suitability maps FAO framework Suitability for three systems System 1: small pits, runoff strips, small runoff basins, semi-circular bunds System 2: contour ridges System 3: contour bench terraces

21 Land suitability maps Add to suitability maps the soil constraints and land use constraints

22 Hydrological analyses Main purpose: identify potential sites for micro- and macro-catchment WH Procedure of watershed modelling with SWAT Watershed delineation: DEM setup, stream delineation, watershed outlet and inlet definition Land use/land cover maps Soil data Weather data: coordinates of nearest 11 weather stations Creating hydrologic response unit

23 Outputs, example predicted runoff coefficient and runoff volume for subwatersheds within main watersheds Hydrological analyses

24 Socio-economic characterization Distribution of communities and road network Linking community location with socio-economic characterization

25 Data integration and utilization Criteria for water harvesting interventions: Suitable land for WH with minimum soil constraints for use Sites should be close to collaborative farming community (with livestock) Accessible sites Suitability and soil constraints Suitability and soil depth Suitability and slope Suitability and accessibility

26 Data integration and utilization Criteria for supplemental irrigation: Availability of sufficient runoff water to be harvested and stored Availability of suitable land to use the harvested water in the vicinity of the proposed dam The presence of collaborative community Only two sites are suitable in this watershed

27 Data integration and utilization Based on these Criteria potential sites were identified at watershed level and at field level Research & Development stage: These were visited in the field and relevant interventions were designed and implementation started

28 Concluding Remarks Integration of biophysical elements (watershed characteristics, land suitability and hydrological characteristics) with socio-economic elements (community distribution and characteristics, accessibility and willingness to cooperate) and the involvement of inter-disciplinary team is crucial to achieve relevant watershed selection and characterization The results are well documented for future use and for out-scaling of the approach for similar agro-ecosystem

29 Concluding Remarks SWAT provided useful information to support the watershed selection, characterization and development process There is a need to raise awareness about the concepts of using the watershed as working units for Integrated land and water resources management

30 Publication Ziadat, F. and Oweis, T Selection and Characterization of Integrated Benchmark Research Watersheds in Libya. ICARDA, Aleppo, Syria. iv pp. f.ziadat@cgiar.org to request a copy