Water Resources Assessment

Introduction

(Adapted from GWP 2008; EMPOWERS PARTNERSHIP n.y.)

Water resources assessment (WRA) is the process of measuring, collecting and analysing relevant parameters on the quantity and quality of water resources for the purposes of a better development and management of water resources.

WRA is a tool to evaluate water resources in relation to a reference frame, or evaluate the dynamics of the water resource in relation to human impacts or demand. WRA is applied to a unit such as a catchment, sub-catchment or groundwater reservoir. It is part of the IWRM approach, linking social and economic factors to the sustainability of water resources and associated ecosystems. Depending on the objective of the assessment, WRA may look at a range of physical, chemical and biological features in assessing the dynamics of the resource.

Water resource assessment is a systematic study of the status of water services and resources, and of trends in accessibility and demand within a specific domain of interest.

The international Glossary of Hydrology (HUBERT n.y.) defines water resources assessment as the “determination of sources, extent, dependability and quality of water resources for their utilisation and control.”

Purpose of Water Resources Assessment

(Adapted from EMPOWERS PARTNERSHIP n.y.)

Conducting water resources assessment in your area helps clarifying the following issues:

• Current status of water resources at different scales, including inter-and intra-annual variability
• Current water use (including variability), and the resulting societal and environmental trade-offs
• Scale related externalities, especially when patterns of water use are considered over a range of temporal and spatial scales
• Social and institutional factors affecting access to water and their reliability
• Opportunities for saving or making more productive, efficient and/or equitable
• Efficacy and transparency of existing water-related policies and decision making processes
• Conflicts between existing information sets, and the overall accuracy of government (and other) statistics

By conducting a water resources assessment (WRA), you are establishing a common, agreed and trusted information base that can be used by stakeholders as a basis for informed and effective decision making. In order to improve your sanitation and water system with the aim to make it more sustainable, it is of prime importance to conduct a water resources assessment. Especially when a comprehensive and large-scale change in the water and sanitation system is envisaged, it is crucial to know the various parameters related to water quality and quantity in your area. If you, for example, want to save water and make water use more efficient, it is important to know the various water consumers and their actual water consumption. Only with a sound understanding of the present situation of water consumption in your project area, you can decide where and how to save water.

Components of Water Resources Assessment

(Adapted from UNESCO and WMO 1997)

In order to conduct a comprehensive water resources assessment, you need various experts from different backgrounds who conduct, collect and analyse data required for the assessment.

The following graph illustrates the main components of a water resources assessment:

• Collection of hydrological data - the collection of historical data on water cycle components at a number of points distributed over the assessment area such as quantity and quality of surface and groundwater.
• Collection of physiographic data - obtaining data on the natural characteristics of the terrain that determine the areal and time variations of the water cycle components, such as topography, soils, surface and bed rock geology, land-use and land-cover. These characteristics are designated for brevity as physiographic characteristics.
• Collection of data from basic and applied research - further research related to water resources can be essential especially when some data is missing or the available date is out of date. Furthermore, research may be needed in order to develop the required technology used for the water resources assessment.
• Education and training – All the basic water resources assessment activities require skilled manpower and this in turn require training and education of the manpower need (see also developing human resources).
• Techniques of areal assessment of water resources - techniques of transforming data into information and of relating the hydrological data to the physiographic data for the purpose of obtaining information on the water-resource characteristics at any point of the assessment area.

Things to Consider

(Adapted from GWP 2008)

A water resources assessment often needs to be carried out in several steps of increasing complexity. A rapid water resources assessment may help identify and list the most important issues and identify priority areas (you could also see “understand your system” for this purpose). On the basis of this early assessment, more detailed investigations may be required. Assessments for large or long-term projects need to include the examination of changes in land use and possible soil degradation as well as climate variability and change.

Linking water resources assessment to environmental impact assessment has shown to build cross-sectoral linkages and heighten awareness of key issues.

Strategic impact assessment can help in the analysis of change capacity of a river basin, to protect both quantity and quality.

Traditional water resource assessment aimed to provide the basis for the supply of infrastructure to meet projected needs. Assessments have a much wider remit in an IWRM perspective, incorporating cross-sectoral tools such as:

• Demand assessment, which examines the competing uses of water with the physical resource base and assesses demand for water (at a given price), thus helping to determine the financial resources available for water resource management.
• Environmental impact assessment and strategic impact assessment collect data on the social and environmental implications of development programmes and projects. Environmental impact assessment is an important tool for cross-sectoral integration involving project developers, water managers, decision-makers and the public. It can be seen as a special form of water resources assessment.
• Social impact assessment, which examines how social and institutional structures affect water use and management, or how a specific project might affect social structures.
• Risk or vulnerability assessment, looking at the likelihood of extreme events, such as flood and droughts, and the vulnerability of society to them.

Content Example for a Water Resources Assessment

(Adapted from US ARMY CORPS OF ENGINEERS 1999)

The following list is an example how the content of a water resources assessment could look like for your project area:

1. Introduction

2. Country Profile

• Geography
• Population and social impacts
• Economy
• Flood control
• Legislative framework

3. Current Uses of Water Resources

• Water supply
• Domestic uses and needs
• Industrial/commercial uses and needs
• Agricultural uses and needs
• Hydropower
• Stream gauge network
• Waterway transportation

4. Surface Water Resources

• Precipitation and climate
• Rivers and basins
• Lakes and swamps
• Deforestation effects

5. Ground Water Resources

• Aquifer definition and characteristics
• Hydrogeology

6. Water Quality

• Surface water
• Ground water
• Domestic waste disposal