Water Uses Nadim Farajalla, PhD Environmental Hydrologist American University of Beirut

Water resources are exploited for use in the following sectors: –Agriculture –Municipal/Domestic –Industrial –Recreational A non-exploitation use is: –Ecological

Domestic/Industrial Sector The following are the supply oriented components: –Sources of water supply –Treatment facilities –Storage facilities –Distribution networks –House/establishment connections

Domestic/Industrial Sector The general wastewater components are: –Sources –Collection networks –Treatment facilities –Discharge locations

Why Treat Wastewater? Odor generationUnpleasant odors from raw sewage disposal Water QualityPollution due to high BOD, high nutrient load, pathogenic organisms, suspended solids, etc. Public HealthHigh incidence of waterborne diseases BiodiversityPossible negative impact on fauna and flora; Coastal degradation AgricultureIrrigation with raw sewage - possible contamination of soil and crops Economic AspectsCost of treating illness; Cost of lost working days due to illness; Indirect costs of water treatment; Loss in national income (decrease in tourism and investments) Visual ImpactImpact on natural landscapes and amenity value

Reuse and Recycle An average household may generate 135 to 180 m 3 of wastewater annually: Irrigation: –Some crops –Silviculture (Managed Forests) –Golf Courses –Landscaping Graywater Recycling: –Use for flush toilets

Agriculture

5,500 5,000 4,500 4,000 3,500 3,000 2,500 2,000 1,500 1, Water use (cubic kilometers per year) Total use Agricultural use Industrial use Domestic use Year Global Water Use

 Rapid growth in domestic and industrial water demand  Increasing costs of water development  Wasteful use of existing water supplies  Groundwater over-pumping and degradation of irrigated cropland  Threats to ecosystems, declining water quality  Subsidies, distorted incentives, and poor cost recovery  Low rainfed crop yields Key Challenges for Agricultural Water Resources

Effective Water Resources Use For Agricultural Production Natural Factors Precipitation Evapotranspiration Infrastructure Reservoir storage Water distribution and use systems Water Policies Water allocation among sectors Water prices Committed flow for environment Investment in infrastructure Water Pollution Variables Influencing Agricultural Water Resources

Water in Agriculture Two major water components/systems in agriculture: –Water delivery systems (canals, reservoirs, etc) –On-farm systems (irrigation systems, storage facilities, etc.)

Inefficiencies in Water Conveyance and Irrigation System Maintenance Poor management of irrigation systems leads to conveyance losses of up to 50 percent The social benefit of canal maintenance is greater than the private benefit. Ignoring this has led to under investment in canal maintenance, resulting in: –shorter canal systems than optimal –over-application of water upstream

Inefficiencies in Farm-level Water Management Poor farmer selection of crops and irrigation technologies Conservation technologies increase water use efficiency but some may lead to higher cost per acre There are low tech “drip” like technologies – but are unused Low pricing of water does not justify adoption of water conservation approaches and technologies Effective pricing of water and charges on drainage water quality will lead to adoption of water conservation approaches and technologies

System Ownership Water systems run by a water user associations are more efficient and better maintained (Madagascar, India, China). WUA tax members and improve distribution and pricing.

Options for Improvements

Options for Improving Water Use in Agriculture [adapted from Wallace and Batchelor (1997)] 1.Agronomy: Crop management to enhance rainfall use or to reduce evaporation (crop residues, conservation tillage, plant spacing); Improved varieties; and Advanced cropping strategies (double-cropping, rotations) to take advantage of lower water demand times or periods with higher rainfall.

Options for Improving Water Use in Agriculture [adapted from Wallace and Batchelor (1997)] 2.Engineering: Irrigation systems that reduce application losses and improve application uniformity; Enhanced rainfall capture (crop residues, deep chiseling, furrow diking, etc.)

Options for Improving Water Use in Agriculture [adapted from Wallace and Batchelor (1997)] 3.Management: Demand-based irrigation scheduling; slight to moderate deficit irrigations to promote deeper soil water use; avoiding exceeding critical root zone salinity levels; and preventative maintenance of equipment

Options for Improving Water Use in Agriculture [adapted from Wallace and Batchelor (1997)] 4.Institutional: User participation in district (project) operation and maintenance; water pricing and legal incentives to reduce water use and penalties for inefficient use; and training and educational opportunities

Caveat When considering water allocation the following must be considered: –Water in agriculture supports more than crop production – it sustains a way of life

Concepts

Water Productivity – Definition Physical:Amount of marketable product (e.g. kg rice) per volume of water used Economic: $ output per $ water used Combined: Value ($) of output per volume of water used “More Crop Per Drop”

Water Productivity Principles Enhance marketable yield of crops for each unit of water transpired Reduce water losses other than those lost to evapotranspiration Enhance the effective-use of rainfall, water stored in the domain of interest, and water with marginal quality.

Water Productivity - Make Existing Systems More Productive Strengthen management Ensure integrity of infrastructure Rehabilitate existing investments Improve on-farm water use Participatory management by farmers Private sector in investments and management

Virtual water Value of water varies by location. Defining a water shortage as a situation where water per capita is below a certain level is not always useful. A region with minimal water can use it productively and generate resources to buy water intensive crops at a cheaper rate than producing them locally. For example, an acre-foot of water used in flower production is equivalent in the value of productivity to acre-feet used in wheat.

Water Security

Context –Worldwide, more than 1 billion people lack access to safe drinking water. –80 percent of the earth’s urban residents may not have adequate potable-water supplies. –Around 0.008% of fresh water is currently available.

Addressing Water Security Integration of water resources fully into the planning process Continued reform and capacity building Development of water resources infrastructure Reappraisal of existing investments Recognition of climate change and/or variability as risks to be managed

Addressing Water Security Increased water productivity Water for food Water for power generation Water for environmental functions Diversification of type and size of interventions Diversification of financing mechanisms both public and private

Food Security

FOOD SECURITY vs. FOOD SELF-SUFFICEINCY –Food security is “…people having access to sufficient stocks and supplies of food to provide a nutritionally adequate diet” –Food self-sufficiency: a country growing its own basic food requirements

What do you think………… Food security or food self-sufficiency? Water security or food security? Water security or food self-sufficiency?