TOR for Geotechnical/Site identification for the Construction of one Strategic Hafir dam/Balley in Hiiraan region, Somalia
- Job category: Tender/Bid/RFQ/RFP
- Post date:3 Oct 2021
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TOR for Geotechnical/Site identification for the Construction of one Strategic Hafir dam/Balley in Hiiraan region
Save the Children has been making a difference in children’s lives in more than 120 countries. We are the world’s largest independent child rights organization, underpinned by a vision in a world in which every child attains the right to survival, protection, development and participation. Our mission to inspire breakthroughs in the way the world treats children, and to achieve immediate and lasting change in their lives.
To ensure delivery of this mission, Save the Children collaborates with local governments, multilaterals, grassroots, non-governmental organizations and others to identify and address supply and demand-related bottlenecks in both humanitarian and development contexts. Save the Children has been engaged in the WASH sector in Somali for more than 20 years.
SCI is seeking geotechnical consultant/firms to support analysis and design work for new Hafir dam (Balley) In Hiiraan area.
As severe drought grips most parts of Somalia, Lack of safe drinking water access has contributed to staggering levels of diarrheal diseases, particularly among the young, the immune-compromised, and the poor. Unsafe water sources complemented by poor sanitary environment are a major cause of malnutrition throughout Somalia.
Existing water sources in Hiiraan are already overburdened as a result of the drought’s impact on ground water levels. While there are water spots, many have gone into disrepair due to a lack of resources (funds, expertise) to fix them. Additionally, the continuing inflow of IDPs as a result of floods and recurrent flooding, as well as the closure of WASH programs by certain humanitarian organizations, are placing further pressure on the existing water supply system. The current amount of water supplied is insufficient to satisfy current demand, numerous families are unable to reach the required daily intake of 15 liters per person.
Save the Children is intending to construct a new Balley (Hafir dam) in Hiiraan to ensure that the resident communities and nearby pastoralists have access to adequate water for at least four months after the rainy season. The new Balley will serve over 15,000 people in the short term and 17,000 people in the long term (taking into account an average urban growth rate of 4 percent per annum). By striving for a minimum of 30 liters per person each day. The new Balley has a capacity of 30,000m3, which is sufficient to provide 224cubic meters of water per day to the community for four months after the rainy season. This vast amount of water can sustain local communities and livestock, as well as be utilized to irrigate small-scale farms, thus increasing the area’s food security.
Save the Children will engage a consultant/firm to conduct a comprehensive geotechnical and topographic assessment of the area selected for the new Balley/Hafir.
- OVERALL OBJECTIVES OF THE SURVEY
The primary objective of this project is to undertake a geotechnical survey with the objective of determining an appropriate location for a new dam with the potential for rain water harvesting. This will be accomplished by conducting geotechnical and topographic investigations at the proposed dam site and developing feasibility, preliminary, and detailed designs for the proposed dams based on the consultant’s experience and on macro and micro and micro studies
- Specific objectives
- Carry out comprehensive geotechnical and topographic studies to determine the most appropriate location for Hafir dam construction.
- Identifying and appraising 2 or 4 sites in the target area that can be potentially developed for surface reservoirs and carrying out all relevant technical investigations.
- Evaluate if the site is easily accessible and approachable from the surrounding neighborhoods.
- Conduct soil investigations in the area of the dam site in order to identify appropriate materials for the dam’s construction and to get an understanding of the landform and geology.
- Evaluate the area’s catchment and available seasonal rainfall in order to determine if there should be sufficient rain to fill the Hafir dam.
- Detailed dam design –develop detailed drawings including dam depth, spillway height and width.
- Scope of Required Services for Balley assessment
Task 1: Collecting Existing Data
Undertake a desk study of favorable sites using georeferenced GIS/DEM data (WorldDEM data, QGIS format) to identify the main drainage basins and select several sites for further research in the field. The consultant will collect any existing data from the Ministry of Water Resources (MoWR) and other agencies like FAO etc, for the project area that will be useful for this assignment, including thematic mapping (topography, geology, hydrogeology, land use, and vegetation cover), satellite images (if available), hydrological data (runoff and sediment transportation), hydrogeological data (groundwater), and meteorological data (rainfall and evaporation), and geological data (ground conditions).
Task 2: Preliminary Assessment & Feasibility Studies of Potential Dam Site
The consultant will select two or three sites from target villages. The selected sites will then be inspected to verify topography by using highly accurate differential GIS (RTK Base and Rover) of mm accuracy in order to create surface contours line spacing of maximum 2.0 m, ground conditions, and the catchment areas feeding the selected sites. The siting/identification of the potential areas will be done in close consultation with the stakeholders and guidance of the beneficiaries to ensure buy-in and assessing any areas of potential conflict and land acquisition, access and safety.
For each site, the consultant will conduct comprehensive topographic and geotechnical surveys of the areas around the structures and reservoir at each site in order to ascertain the reservoir capacity and evaluate the ground conditions. The soil survey will verify if the geotechnical characteristics of the area match the requirements and whether adequate construction materials are available. The consultant will excavate soil test pits inside the embankment footprint to ascertain the depth, thickness, and geotechnical characteristics of the subsurface layers. A minimum of 5 to 6excavations (pits) is required at each selected site for Balley.
the consultant will analyze rainfall data (average annual rainfall, year-to-year variability, and distribution within a single year) for the area under study, and if such data does not exist, the consultant will estimate rainfall features utilizing data collected from neighboring areas with similar altitude and exposure characteristics. These characteristics will be used to estimate the dams’ storage volumes. The consultant will also take into account annual evaporation and seepage losses of the dam.
For the sites, the consultant will produce localized maps of the dam locations and catchment areas using the information/data gathered in Task 1. Each site’s watershed boundaries will be delineated and classified based on its topography, geology, and drainage characteristics. The consultant will create cross- and longitudinal sections of the water flow in order to enable preliminary dimensioning of the structures for the sites. This would need specialist software such as a Geographical Information System (GIS) for map creation, Computer Aided Design (CAD) for visually summarizing the data gathered during reservoir surveys, and other software for estimating hydrological and hydraulic features.
The consultant will recommend appropriate water treatment options and methods for abstracting and distributing water from dams for human consumption and animal use. A preliminary project design will determine the quantities of materials required and the means necessary to build the structures.
Task 3: Detailed Engineering Design for the Balley
The Balley structure will be designed and verified based on the selected site, including the water storage capacity for an earth fill dam that will supply water year-round or semi-annually. The spillway’s dimensions must be determined. Other facilities necessary for the Balley, such as animal troughs, reservoirs, and inlet/outlet canals, will be designed in detail. For each component, maps and sections with clearly defined levels must be created. The earth embankment’s cross-sections shall be designed to minimize hydraulic seepage through and under the dam. A comprehensive work plan will be developed for each phase of construction to ensure the most efficient use of available resources. Furthermore, the consultant will also prepare detailed designs for the agreed method of water abstraction including carrying out necessary detailed topographical surveys to establish construction levels. During the design phase, it will be important to take into consideration, and try to minimize, future maintenance tasks.
Additionally, the consultant will provide technical specifications, bills of quantities, detailed drawings, and engineering cost estimates for the Balley and associated works.
The firm/consultant is anticipated to provide the following services:
- A report on the inception assessment and methodology for comparing it to the current terms of reference and justifying any differences
- The fieldwork presentation, interpretation, and conclusion to be presented to the SCI technical team.
- A comprehensive final assessment report
- Detailed engineer design of the Hafir dam in detail, as well as associated work including a water storage tank, water collecting stations, and an infiltration shallow well.
Work Plan (sample work plan required)
|ACTIVITY DESCRIPTION||Time Line|
|1. Secondary data gathering, document review, and travel to the Dam inspection location|
|2. Collaborate with target communities and local governments to identify potential sites. And perform all required field work, including geotechnical, topographic, and soil assessment.|
|3. Produce comprehensive report of the assessment|
|4. Prepare detailed engineering design of the Hafir dam with all associated work|
Documents/application will cover the following:
- A technical proposal including schedule, methodology and budget for the assessment.
- Financial daily fees in US dollars.
- Updated profile/curriculum vitae for the consultants/individuals
- Previous experience with comparable assignments of this exercises.
- At least three references of past assignment,
Save the Children seeks to invite qualified consultants/firms who meet the following requirements to submit their detailed narrative and financial proposal on how to undertake the assignment.
- Technical proposal on how the assignment will be conducted including methodologies, data analyses and interpretation, reports and schedules. (List software to be used for analysis)
- Proven field technical and field experience of Consultant with Master’s degree in geology, hydrology, Water Enginer, Civil engineer or in any related field and having good experience of working in this sector.
- Consultancies performed in the last 10 years especially with reference letters for each Dam assessment consultancy
- Proof of availability of all the equipment’, personnel and ability to mobilize them on short notice (Include list of equipment, Brand/Manufacturer, CVs of the personnel) to perform the survey.
- Submit a detailed financial proposal including all professional fees, report costs and subsistence costs. Please note all costs must be broken down into details (no lump sums, no contingencies etc)
- The SC will select a geotechnical consultant based on their technical expertise and experience.
The consultant/firm will be responsible for their own security; insurance while in the field and Save the Children will not be responsible for any injuries or damages incurred during the assignment. The costs submitted must be inclusive of all anticipated expenses.
SCI will consider applications from both experienced professionals and expert firms on the field of the study. Consultants are requested to submit the proposal with a cover letter and their expected remuneration for this exercise.
Applications should include:
- A proposal of the above Terms of Reference including methodology, schedule, budget.
- A financial offer including daily fees in US Dollars
- Up-to-date curriculum vitae(s) of the lead consultant and relevant team members,
- Description of available equipment for the assignment,
- Evidence of past experience in undertaking similar assignments (three most recent documents preferred) of similar works done,
- Three (3) references of previous assignments.
Share your application documents with email; CSS.LOGISTICS@savethechildren.org with the subject line of the email body “Application of Geotechnical/Site identification for the Construction of one Strategic Hafir dam/Balley in Hiiraan region
Deadline for submission is 16th Oct–021
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