Water quality - Dispuut Watermanagement

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Terms of Reference
As part of the PPP ‘Harar Sustainable Water Services’ a regional water resources assessment needs to
be prepared, the current and future water demands will be assessed and climate resilient water resources
development scenarios will be identified. The student will contribute to objective 2 of the project:
Water resources conservation, allocation and protection strategy developed with all stakeholders.
Relevant activities and results for this objective are listed below:
Objective
Water resources conservation, allocation and protection strategy developed with all
stakeholders
Description
Based on a stakeholder approach, the activities under this activity will provide an a systematic
overview of the current water potential, water needs and a strategy to increase the water availability
where needed through investments in water conservation and tapping of still unknown or unused
(ground)water resources along with measures to improve the siting and success rate of wells and to
reduce system failure during use.
Task
Activities
1.
Regional water resources
assessment
1.1. Collect and study available publications and reports
1.2. Acquire maps and digital data for base map production and analyses
1.3. Mapping of hydrogeological conditions, topography, natural
vegetation, land use and climate data
1.4. Inventory of water sources (quality and quantity), water use and
population distribution
1.5. Synthesis report (and maps) available showing potential and gaps in
available water resources and options for enhancement (incl water
buffering)
2.
Assessment of current and future
water demand
2.1. Mapping of current population and main economic activities
2.2. Assessment of demographic changes based on historic trends,
socio-economic development, federal and regional plans, food
security, WASH strategies and climate change impacts
2.3. Prepare a spatial overview of the 2020 and 2030 water demands
(drinking, industrial, agriculture) and gap analysis between water
need and water availability.
2.4. Overview available of water quality and protection issues related to
the various users (notably agriculture versus domestic and industrial
water demands
The student will carry out the following tasks (in cooperation with a student from the Haromaya University)
- Prepare a digital elevation map
- Prepare a detailed hydrogeological map 1:100000
- Prepare a land use map from multispectral satellite imagery
- Conduct field surveys to collect ground truth for the land use map
- Collect and analyse available meteorological data
- Collect and analyse available hydrological data
- Assessment of the population distribution and water use
- Watershed characterization
- Prepare water balances of the two watersheds
- Determine the water resources development potential
Project Background
Project name:
Sustainable Water Services in Harar Regional State (SWSH)
Project location:
Harar Regional State, Ethiopia
Sub-sector:
Improved access to safe drinking water and sanitation
Applicant:
Vitens Evides International BV
Partners:
HEINEKEN Brewery SC
Harari People Regional State (HPRS)
Harar Town Water Supply and Sewerage Service Authority
(HWSA)
Ethiopian Catholic Church-Social and Development Coordinating
Office of Harar
MS Consultants
Acacia Water
DHV BV
Project purpose:
The proposed PPP aims to ensure long term water availability for
urban, rural and industrial consumers in Harar State currently
facing urgent water shortages, affecting over 300.000 people.
Summary project intervention:
This project will lead to improved water access and availability in Harar Regional State, Ethiopia, that
suffers from heavy water shortages. In 2004, Harar’s main water source, Lake Haramaya has dried up,
due to unsustainable exploitation practices. Water users, including consumers and industry in Harar, are
faced with water scarcity. Competition for the available water is high and increasing. This is amplified by
lack of expertise of key water actors (HPRS and HWSA) in the fields of water resources management and
water services provision.
In order to alleviate water scarcity, a new urban water system has recently been realized through African
Development Bank financing, bringing water from near Dire Dawa over a distance of 71 km and a height
difference of more than 800 m to Harar city. However, HWSA is not able to sustainably operate this
system because of technical problems (the hardness of the water is likely to disrupt the system within 2-4
years) and lack of experience. At the same time, the organisation is not able to raise more funds for
investments because of its poor financial situation and the high level of Non Revenue Water (45%). The
Rural Water and Sanitation Support Unit (RWSSU) of HPRS has insufficient capacity to enhance water
conservation approaches and improve rural water supply services, while only 46% of the people in rural
Harar has access to safe water. Hence structural poverty alleviation is urgently requires an intervention to
sustainably improve regional water supply.
The interventions include:
 Development of an integrated water resources allocation and conservation approach within the context
of a long term, climate-proof water resources master plan.
 Demonstration of innovative and sustainable abstraction practices and water conservation approaches.
 Capacity development to turn HWSA into a financially and self reliant water operator. Activities include
NRW reduction (from 45% to < 30%) and increasing HWSA’s customer base with at least 25,000
people.
 Design, construction, operation & maintenance support and hand-over of a decalcification unit at Dire
Dawa well fields to ensure long-term system integrity of the new urban water system.
 Demonstration of sustainable water abstraction and protection approaches through 3-5 pilot schemes
 Capacity development at the RWSSU to decrease system failure in the rural areas and develop an
investment plan.
 Construction of rural water supply schemes to provide access for at least 25,000 people.
Impact: water stress and limited access to safe & reliable water resources will be relieved for 205,000
people in Harar Regional State and 98,000 people in the neighbouring cities Alemaya and Aweday
(poverty alleviation). The development of a water resources allocation and conservation approach will
facilitate industrial activities and irrigated agriculture (sustainable economic growth). Key water actors will
be capacitated in water resources management & conservation and provision of sustainable water
services (enhanced self reliance).
Specific background
Study area
The boundary of the study area for the regional assessment will be based on the watershed boundaries.
The town of Harar is located on the water divide between the watersheds of Wadi Errer (east) and Wadi
Gobele (west). The hydrogeological aspects of the regional water resources assessment will concentrate
on these two watersheds (figure 1). The areal extent of these two watersheds is quite large: 2400 km2
with a population of 970,000 as estimated from 2007 census data.
The management of the water resources is under authority of institutions that follow administrative
boundaries (kebele, wereda, zone and region). The availability of information on installed water schemes,
water points and water demand is therefore with the water management organizations.
Figure 1 Study area
Hydro-geological description
The study area is situated in the wadi Shebelle watershed near the water divide with the Awash basin to
the north. The area is underlain by Precambrian basement rocks consisting of granite, migmatite and
gneisses. The main water bearing formations in the area are Mesozoic sediments (sandstone and
limestone) that overlay the basement complex and Quaternary alluvial deposits. Except for its weathered
zone and local fractures, the basement complex has limited prospects as a source for water supply.
Most of the Mesosoic sediments have eroded but some isolated patches remain on higher grounds near
the water divide between sub-catchments. These remnant patches consist of karstified limestones of the
Hamanlei formation underlain by a thin layer of sandstone (Adrigat formation). Due to the limited primary
porosity of the limestone groundwater occurs mainly in fractures. At the fringes of the patches springs
emerge at the contact with the basement rocks. Many of these springs are perennial and are used as a
permanent source of water supply. Examples are the Sofi and Burka springs near Harar and the Ginella
spring of the Harar Brewery.
The alluvial deposits along the wadis are widely exploited by shallow wells and form the main source of
water supply in the rural areas. In the Northern part of the study area larger areas of relatively thick
alluvial deposits occur. These alluvial aquifers are extensively exploited by shallow wells and boreholes
with motorized pumps and water supply schemes (Alam Maya, Adele, Finkile). Until recently, Harar town
depended on these aquifers for its water supply.
Topography
A Digital Elevation Map (DEM) of the study area will be prepared based on a combination of Shuttle
SRTM and ASTER data with a horizontal resolution of 30 meter. This DEM will be the basis for the
delineation of the sub-catchments in the two main watersheds as well as the interpolation of the
precipitation data over the study area. In addition, the DEM will be used to create derived products (such
as flow accumulation, slope and compound topographic index) that will be as input for the identification of
areas with prospects for water buffering interventions.
Moreover digital, geo-referenced topographical maps 1:50000 and 1:250000 will be acquired to facilitate
the preparation of base maps.
Climate
The climate in the study area is mild, with average temperatures ranging from 14 to 28 °C in Harar town.
Rainfall is abundant, ranging from 650 to 1000 mm/year with two wet seasons: February to May and July
to September.
Figure 2 Average monthly temperature and rainfall for Harar
Detailed data on precipitation, evaporation, potential evapotranspiration and temperature will be collected
from the National Meteorological Agency. It should be noted that the only ‘class 1 station’ in the study
area is Alem Maya. All other stations record only daily precipitation.
The annual precipitation depends not only on the geographical location but also on the altitude.
Using the historical data, supplementary data from available studies and reports, NMA data and the DEM,
an isohyet map will be prepared that is used to determine the annual precipitation per sub-catchment.
Depending on availability of data, rainfall intensity will be analysed.
Vegetation & Land Use
No suitable vegetation and land use maps are available for the study area. Since these maps are
essential for the water resources assessment, the maps must be created from remote sensing data
(multispectral images). Sources are Landsat 7 or Landsat 8 (since May 30, 2013) with a resolution of 30
meter. Although this resolution is sufficient for land use and vegetation mapping, ground truth must be
collected for calibration of the classification.
Current water abstraction
No comprehensive dataset on the current water abstraction is readily available. Data will be collected
from the water office in Harar, during a field survey and through the project’s stakeholder platform
Water quality
Although the groundwater and surface water is generally of good quality, the limestone aquifers may
show elevated salinity due to dissolution of gypsum and evaporates. Due to poor sanitation practises the
shallow groundwater in urban areas is subject to bacteriological contamination.
Except for some sporadic analysis no data is available on the water quality. Because the water quality
forms an integral part of the water resources assessment water samples will be collected from selected
sources and a water quality mapping will be carried out.
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