CONSULTANCY TO PROVIDE SERVICES ON HYDROGEOLOGICAL SURVEY FOR NEW BOREHOLES AND BOREHOLE WATER RESOURCE QUANTITY AND QUALITY ANALYSIS FOR EXISTING BOR

TERMS OF REFERENCE

CONSULTANCY TO PROVIDE SERVICES ON HYDROGEOLOGICAL SURVEY FOR NEW BOREHOLES AND BOREHOLE WATER RESOURCE QUANTITY AND QUALITY ANALYSIS FOR EXISTING BOREHOLES AND MITIGATION MEASURES

Habitat for Humanity Kenya seeks to hire a Consultant/Consulting firm with the capacity to conduct a comprehensive Hydrogeological /Geophysical Survey in 3 villages of Masinga Sub County, Machakos County (Mukameni, Thatha and Mukusu Villages) and related studies for prospecting on identification of the site for drilling of a new borehole and submit an accurate report to guide the drilling process. In addition, the consultant will integrate a comprehensive water quantity and quality analysis of groundwater sources for 16 dormant existing boreholes in Masinga Sub-County and identify and/or recommend mitigation measures to address existing water quality and system operational challenges.

1. Background and Rationale

Habitat for Humanity Kenya (HFHK) is among the 70 country affiliates of HFH International. In Kenya, we were registered in 1982 as Non-Governmental Organization, with the goal of enabling low-income families access decent and affordable shelter. In the last 40 years since its registration in Kenya, HFHK has supported more than 500,000 families across 9 counties in Kenya through housing micro-finance and direct construction. HFHK is currently operating in Laikipia, Homabay, Kisumu, Tana River, Machakos and Makueni. In its current Business Plan (2020-2025) HFHK has outlined four programmatic areas, namely: Financing for Owner-led Construction (FOC); Settlement-Based Practice (SBP); Secure Land Tenure (SLT); Disaster Risk Reduction & Response (DR3) as being its areas of focus in supporting communities in the listed areas through donor funding. HFHK’s programs has been based in Machakos County since 2016, with a portfolio of interventions on Home Construction, Water Sanitation and Hygiene (WASH), Schools Infrastructure. In accomplishing the tasks in this assignment, the consultant is expected to work very closely with the HFH Kenya management, Machakos County government Department of the Ministry of Water, Sanitation and Irrigation, the national government administration and community leaders.

The goal of HFHK is to ensure more families and communities have access to safe drinking water and increased household incomes through agricultural production through WASH intervention such as drilling new, rehabilitating, and solarizing boreholes, constructing water kiosks, establishing water committees, and constructing weirs. Through these interventions, the project will enhance access to clean water for domestic use and agriculture for enhanced food production. Construction of sanitation infrastructure and shelter for the LIH in Masinga Sub- County will be enhanced with investments in water supply.

Machakos County is one of the 47 counties in Kenya with a population of 1.4 million in 2019[1]. The County covers an area of 6,208 km2 and is in the former Eastern Province. The County receives annual rainfall of about 500 mm with variations depending on the altitude. Temperatures range from 18 to 29°C. 90 percent of food production activities in the County are dependent on rain-fed agriculture.

The rain crises and high evapo-transpiration have depleted surface water including dams, water pans and wells.[1]

Between the year 1981 and 2011, the mean monthly and annual temperatures in Masinga catchment shows an increasing trend. Both the minimum and maximum annual average trend-lines indicate that the catchment temperatures are increasing at indices of 0.026 and 0.015 respectively. Based on this, the mean minimum and maximum catchment temperatures will rise with a value of about 0.260C and 0.150C respectively after every decade. From the past research findings, it has been proved that temperature change influences the area’s hydrological cycle because it affects both evapotranspiration and soil moisture changes. The temperature increase in Masinga catchment causes a broad range of issues such augmented evaporation, low precipitation and season shift. Extreme weather like floods and droughts also become more frequent and with greater magnitude over the whole region. Increasing catchment temperatures trend-lines in Masinga Sub County conforms to global warming effects which occur because of climate change, among other effects this results in increasingly unpredictable weather patterns.[2]

A trend analysis for the semi-arid lands of South-Eastern Kenya conducted by South-Eastern Kenya University show that 89% of Kenya, is arid or semi-arid, with serious socio-economic, environmental and developmental challenges. Rapid population growth has led to an increasing demand for land, over-exploitation, and degradation of local natural resources. Masinga Sub- County is largely arid with temperatures ranging from 29 to 36 ◦C. The area also experiences poor rainfall ranging between 450 and 800 mm per year, low levels of technology adoption including inputs such as fertilizer and certified seed, and poor post-harvest management practices.

The population of Masinga is 148,522 (according to the 2019 census report) with 75% of households depending primarily on agriculture for their livelihood. Farmers generally employ intercropping methods, with many keeping poultry and larger livestock for meat, eggs, and milk. Masinga sub- county is primarily inhabited by the Kamba people, who have traditionally been involved in trade but have more recently become widely engaged in small-scale and subsistence agriculture. Masinga sub- County is primarily served by a series of boreholes and shallow wells distributed in the 7 wards. Water is important to all living things and without which life on earth would not exist. Access to safe drinking water and improved sanitation is a fundamental need and a human right which is vital for the dignity and health of all people. About 2.6 million people globally lack access to safe drinking water and in Sub Sahara Africa (SSA) access to clean water for drinking stands at 23.7% as compared to 71% globally.

Human population has increased rapidly in Machakos town since the inception of devolved system of government in 2013. Machakos Water and Sewerage Company limited supplies Machakos town dwellers with treated piped water, however the supply has not been adequate due to the population surge and the infrastructural capital investments required. Therefore, rainwater harvesting and groundwater from boreholes and hand dug shallow wells have become vital alternative sources of drinking water. However, ground water in the proposed project areas is affected by salinity. This has a direct effect on the health of individuals and calls for water quality assessment on the 16 boreholes identified during the proposed project feasibility study.

The dry spell of between January and March has high mean maximum temperature of 260C and 270C. Since this follows the wet season, it results in rapid depletion of water resources. Precipitation, runoff and sediment yield presents the most intricate hydrological trend due to immense spatial variability of Masinga Dam catchment uniqueness and rainfall patterns. Masinga catchment average annual precipitation indicates that the amount of precipitation between 1981 and 2011 is gradually but steadily declining. Masinga catchment precipitation is decreasing by 3.93 mm annually, therefore for a period of 30 years (1981 to 2011) the annual average precipitation has dropped by 117.9 mm on average. Decreasing catchment precipitation adversely affects the river base-flows especially during the dry spells and potential recharge rate for underground water. It is notable that Masinga catchment mean precipitation fluctuates between 587 and 1,622 mm per annum. Even though the average shift in rainfall pattern in the area may not seem significant, the change in precipitation pattern endangers the water resources.

ASSIGNMENT 1- HYDROGEOLOGICAL SURVEY

1. SCOPE AND RATIONALE

HFHK is exploring the possibility of designing a new project for BMZ funding in Masinga Sub- County hence the need for a comprehensive analysis of water quality. The project is aimed at enhancing access to safe drinking water, hygiene and sanitation practices and increased food production through income generating SMART initiatives targeting women and youths in Masinga Sub-County Machakos County by 2029. Considering these challenges, HFHK seeks to engage a hydrogeological consultant or consulting firm to conduct the hydrological study in 3 villages of Masinga Sub County, Machakos County (Mukameni, Thatha and Mukusu Villages). This will include the study of 1 potential site per village totaling to 3 potentials drilling sites. A combination of geophysical methods is to be applied in the assessment of geological sub-surface conditions, including the resistivity method, vertical electrical sounding (V.E.S) and horizontal electrical profiling (H.E.P). The consultant is expected to use hydro-geological data, maps, graphs and cross-section profiles to determine important information such as ground water condition, estimation of drilling depth and identification of stress areas.

The survey shall be carried out in the following order:

1. Carry out ESIA survey. The ESIA study shall include an assessment of the context, components and activities of the project. Which include a survey on the surface hydrology of the area to confirm the implications of project actions on downstream areas and potential environmental impact of the project.

2. Hydrogeological assessment of whole area; maximum extractable water, rainwater harvesting options, water quality concerns and mitigation options.

3. Evaluating the groundwater situation based on compilation of existing relevant data (e.g. drilling logs) with additional classical hydrogeological field data collection (e.g. survey of water points, water levels, water quality) leading to the identification of favourable exploration zone.

4. Carrying out groundwater exploratory field geophysical investigations to identify potential drilling site data for Mukameni, Thatha and Mukusu Villages.

5. Submit ESIA, Hydro-geological and geophysical report

6. Develop (BOQ) total estimated cost budget per site to include Priced bills of quantities, licenses and cost for consultancy fee for the supervision of the actual borehole drilling of the 3 potential site.

   3. Purpose and Objectives

   1.The main objective of this project is to carry out an ESIA study, hydrogeological /geophysical survey with the aim of identifying the aquifer system, to localise drilling site with high potential of good quality groundwater and finally to supervise the drilling process.

   The survey shall be carried out in two phases:

   1).Evaluating the groundwater situation based on compilation of existing relevant data (e.g. drilling logs) with additional classical hydrogeological field data collection (e.g. survey of water points, water levels, water quality) leading to the identification of favorable exploration zone

   ii). Carrying out groundwater exploratory field geophysical investigations to identify exact drilling locations, and

   The survey will focus on site reconnaissance and site mapping, drilling of Trial Pits, Geophysical studies and field tests, determination Water consistence and Water flow and Hydro-dynamic tests

   PHASE 1

   1.Compile and analyze all the available hydrogeological, geological, climatic, meteorological and topographical maps, borehole and surface water records of the area and its environs to:

   1. Assess geomorphological features relevant to groundwater dynamic process (e.g. drainage patterns, vegetation cover variations).
   2. Assess the groundwater potential by establishing a water balance for the area to present a conceptual hydrogeological model of the investigation area

   2.Design an appropriate geophysical investigation strategy that is coherent with the agreed criteria and with the identified target aquifer type (porous, fractured or karstic), the expected depth of the target aquifer and the baseline elevation (estimated depth to groundwater which determines the minimum required investigation depths)

   3.The outcomes of the geophysical investigation strategy should be presented for approval within the Hydrogeological report.

   4.Review of existing data, geological hydrogeological, topographical maps, satellite images, GPS mapping, previous existing hydrogeological and geological studies and borehole site investigations in the area, borehole and surface water records, ground water quality data etc.

   5.Identify and describe groundwater recharge and discharge areas and processes (diffuse versus concentrated recharge) and estimate the groundwater baseline elevation (elevation below which the subsurface is assumed to be saturated): elevation of nearby spring, elevation of lake, flowing river or projected groundwater elevation from nearby wells.

   Geophysical Investigation & Selection of Drilling Sites

   1.Conducts detailed reconnaissance survey of project area to determine location of boreholes. (GPS coordinates, water level measurements, TDS and EC, condition, usage and performance where applicable) inspection of geological, geomorphological and structural characteristics of the investigated area; verification of existing data and findings

   2.Carry out the geophysical investigation according to the investigation strategy and interpret results: select the most suitable borehole drilling sites in the project area, also considering the legal framework and the requirements of the Water Act

   3.The proposed drilling sites shall be marked with a concrete marker, shown in topographical maps and indicated on appropriate sites sketch maps. GPS coordinates have to be provided

   4.Compile the results of the geophysical investigation, including the raw data sets, the qualitative interpretation of the type curves in terms of layer sequence (for VES investigations) and inversions results, and the identification of the drilling locations and precise description of drilling strategy

   5. Establish a Well Design, aiming at maximizing water inflow and minimizing well-head-losses

   PHASE 2

   Submit Hydro-geological and geophysical report

   1. conceptual hydrogeological model of the study area, clearly identifying the target aquifer types (porous, fractured or karstic), their geometrical characteristics (horizontal or vertical­ steep aquifer), the recharge processes and assumed groundwater flow directions well as a water balance of the area.

   2.A figure illustrating the conceptual model and indicating preferential areas for groundwater prospection.

   3.Data base including the compiled geological and hydrogeological data in electronic form (Excel, MS Access, etc)

   4.. Based on the conceptual hydrogeological model detailed description of the investigation strategy and its rationale

   5.Justification of chosen method and investigation depth (recalling target aquifer and groundwater baseline elevation) and description of calibration method (e.g. with borehole logs), description of expected geophysical response of the target aquifer (e.g. electrical resistivity range},

   6.Compile the Phase 1 and phase 2 report into an intermediate hydrogeological/geophysical report and submit to HFH Kenya.

   7.Submit ESIA report.

   4. DELIVERABLES AND TIMING

   1). The consultancy is expected to start working on the study on the 8th of August 2024 for a duration of at least 15 days. Before heading out to carry out the assignment, the consultant is required to submit an inception report and defend the delivery plan through presentation to HFH Kenya management team as shall be scheduled by HFH Kenya during contracting of the assignment. The consultant is expected to work very closely with the HFH Kenya management, Machakos County government, Water Resources Authority Machakos, and local national government administration officials in carrying out the study. The deliverables of this assignment are as follows.

   2). Inception report describing in detail how the consultant plans to deliver the integrated survey,

   3). Environmental, Social Impact Assessment report,

   4). Hydrogeological Report

   5). Reconnaissance Report

   6). Bills of Quantities (BoQs)

   The consultant will also be required to deliver to HFH Kenya all study materials including and limited to:

   1.Soft copies of all data sets both quantitative and qualitative.

   2.The geophysical interpretation model and the graphical plot of the curve and model for the hydrological survey.

   3.Any other non-consumable documents/items that will be used during the planned consultancy.

   5.Qualification and Experience

The consultant or consulting firm should demonstrate expertise in geo-hydrological studies, water resource management, and community water development integrated projects targeting rural populations in Arid and Semi-Arid Lands (ASALs). Previous experience in similar projects within Kenya or similar contexts is highly desirable.

The following qualifications are essential:

• Master’s or postgraduate degree in Hydrology/Geology/Geophysics/Biochemistry or an equivalent with groundwater quality background.
• Minimum 10 years’ experience managing and implementing water mapping projects in ASALs, providing technical quality assurance on GIS and conducting/interpreting hydrological, geological, and geographical data.
• Experience working in Machakos County and proof of previous record of conducting a similar study will be an added advantage.
• Have the capacity to put together a professional team to carry out feasibility studies with similar complexity.
• The consultant should have excellent English writing/communication skills.
• Ability to mobilize all the required equipment/instruments at the required time and place
• Excellent presentation and report writing skills.
• Must be registered by the Geological Registration Board and preferably an active member of the Geological Society of Kenya (GSK).

ASSIGNMENT 2- BOREHOLE WATER RESOURCE QUANTITY AND QUALITY ANALYSIS FOR EXISTING BOREHOLES AND MITIGATION MEASURES

SCOPE AND RATIONALE

Water is important to all living things and without which life on earth would not exist. Access to safe drinking water and improved sanitation is a fundamental need and a human right which is vital for the dignity and health of all people. About 2.6 million people globally lack access to safe drinking water and in Sub Sahara Africa (SSA) access to clean water for drinking stands at 23.7% as compared to 71% globally.

Human population has increased rapidly in Machakos town since the inception of devolved system of government in 2013. Machakos Water and Sewerage Company limited supplies Machakos town dwellers with treated piped water, however the supply has not been adequate due to the population surge and the infrastructural capital investments required. Therefore, rainwater harvesting and groundwater from boreholes and hand dug shallow wells have become vital alternative sources of drinking water. However, ground water in the proposed project areas is affected by salinity. This has a direct effect on the health of individuals and calls for water quality assessment on the 16 boreholes identified during the proposed project feasibility study

Considering these challenges, HFHK seeks to engage a hydrogeological consultant or consulting firm to conduct a comprehensive water quality analysis of groundwater sources for 16 dormant existing boreholes in Masinga Sub-County, identify and/or recommend mitigation measures to address existing water quality and system operational challenges. This study aims to provide critical insights into the status of existing boreholes, assess the likelihood and extent of salinity issues in new boreholes, explore technical solutions for mitigating salinity, and evaluate the operational and cost implications of such interventions. Additionally, the study will identify best practices for sustainable community borehole governance and management, drawing on relevant case studies.

Project scope and objectives:

1. Collection and analysis of secondary data on 16 existing boreholes in Masinga Sub-County, Machakos County, including yield, water quality, and management structures.
2. Assessment of the 16 identified boreholes to determine the feasibility of rehabilitation to address water quality issues.
3. Comprehensive analysis to predict the likelihood or probability of salinity issues recurring in new boreholes based on geological and hydrological factors.
4. Identification of technical solutions/options for fixing salinity issues, including desalination technologies such as RO systems etc, and assessment of their cost impact.
5. Running camera test to ascertain the status of the borehole casings
6. Conduct test pumping of the potential boreholes that qualify for rehabilitation
7. Evaluation of life cycle cost associated with operating and maintaining saline boreholes and investing in desalination interventions.
8. Projection of investment requirements for the installation of water desalination solutions, considering capital and operational costs.
9. Recommendation of best practices for sustainable community borehole maintenance and operation, drawing on successful case studies.
10. Identification and assessment of potential operational challenges and formulation of mitigation strategies.
11. Secondary data collection on existing boreholes, including yield, quality, borehole status, and management structures.
12. To develop and submit a credible groundwater salinity map of the area
13. To establish the possible source of salinity in the 16 boreholes identified in the feasibility study.
14. Submit aquifer formation maps obtained from drill logs of the 16 selected boreholes

Methodology

The comprehensive study on the status of existing boreholes in Masinga Sub-County focusing on water quality analysis and mitigation measures for salinity issues is designed to collect quantitative and qualitative data through primary and secondary data collection methods and procedures. The following water quality analysis procedures are to be used in the study:

1. Secondary data collection and analysis on groundwater (i.e. Borehole depths, yield, water quality) from relevant water related organizations/stakeholders in Masinga Sub- County
2. Primary data collection and analysis for operational boreholes among those identified using the following procedure:

Summary of the Activities to be Undertaken.

1. Lift the pumps before carrying out test pumping for the borehole and 3 No. water wells.
2. Carry out detailed test pumping as per the protocol specified in the TOR/specifications below.
3. Prepare detailed yield test reports (Draw down and recovery) for each test upon completion of the test pump analysis.
4. Re-install the submersible pumps complete with the raiser mains after completion of the test pumping activity for the target borehole.
5. Carry out full physio-chemical analysis for the target borehole and water wells. Water samples MUST be taken towards the end of the test pumping exercise and to government approved laboratories.

Test Pumping

The following tests shall be carried out for each of the boreholes and wells as per the guidelines detailed in below:

1. Calibration Test (1 tests ranging from minimum to maximum discharges each test lasting 15min).
2. Step Drawdown Test, 1 hour for each test.
3. Constant Rate Test for 24Hrs.
4. Recovery measurements -12hrs minimum duration.
5. Allow for full Chemical Analysis after completion of the borehole yield test.

Sampling techniques

• The consultant will ensure proper sampling techniques are employed to guarantee representative results.
• The selection of sampling points to consider factors such as the location, existence of potential contaminants and the intended use of the water.
• Samples must be collected in sterile bottles or containers following standard sampling guidelines to prevent contamination.

Physical parameter measurements

• The consultant must measure and document readings on temperature, turbidity (cloudiness), color, odor, and taste.

Chemical parameter measurements

• The consultant to measure pH level (acidity or alkalinity), dissolved oxygen (DO), conductivity, total dissolved solids (TDS and nitrates,
• The consultant to test for presence of metals and chemicals such as fluoride, lead, manganese, sulphate, phosphates, iron, chloride etc biological indicators.
• The consultant to test for the presence of bacteria, viruses, and parasites. Fecal coliform or E. coli bacteria

Other tests

• Laboratory analysis
• After sample collection, the water samples are to be transported to an accredited laboratory for analysis.
• N/B These test to be carried out in an accredited / certified laboratory to determine the suitability of water use for domestic, livestock and irrigation purposes.

Data interpretation

• Once the laboratory analysis is complete, the consultant to ensure the test results are compared against regulatory standards i.e. WHO and National standards to determine compliance.
• The consultant to interpret data and evaluate the results to identify any potential water quality issues or health risks. If the water quality does not meet WHO standards, , the consultant to recommend appropriate measures to be taken to address the identified problems to guarantee the safety of the water.

The Consultant will be required to present a detailed methodology as part of their technical bid. This methodology should be informed by previous successful experience in similar environments. The Consultant should elaborate on the approaches, tools, and outputs for each component.

6.Deliverable and Timing

The consultancy is expected to start working on the study on 1st of Aug 2024 for a duration of at least 10 working days. Before heading out to execute the assignment, the consultant is required to submit an inception report and defend the delivery plan through presenting to HFH Kenya management team as shall be scheduled by HFH Kenya during contracting of the assignment. The deliverables of this assignment are as follows.

1. Inception Report: Detailed plan outlining the methodology, data collection tools, and timeline for the study.
2. Interim Report: Progress update including initial findings and analysis.
3. Draft Report: Comprehensive document presenting all findings, analysis, and recommendations.
4. Final Report: Revised and finalized version of the report incorporating feedback from stakeholders.
5. Technical analysis and recommendations regarding the feasibility of rehabilitating un-operational boreholes.
6. Professional assessment of salinity issues in new boreholes and recommendations for preventive measures.
7. Evaluation of technical solutions/options for fixing salinity issues, including cost estimates and implementation considerations.
8. Projection of investment requirements for the installation of water desalination solutions.
9. Test pumping yield report for the feasible boreholes for rehabilitation from the assessment
10. Best practice recommendations for sustainable community borehole governance and management, supported by relevant case studies.
11. Identification of operational challenges and formulation of mitigation strategies.
12. Comprehensive report detailing findings from the analysis of existing boreholes, including water quality assessments, salinity levels, and recommended mitigation measures. (Yield and Salinity map of the target boreholes)

7.Qualification and Experience

The consultant or consulting firm should demonstrate expertise in geo-hydrological studies, water resource management, and community water development integrated projects targeting rural populations in Arid and Semi-Arid Lands (ASALs). Previous experience in similar projects within Kenya or similar contexts is highly desirable.

The following qualifications are essential:

• Master’s or postgraduate degree in Hydrology/Geology/Geophysics/Biochemistry or an equivalent with groundwater quality background.
• Minimum 10 years’ experience managing and implementing water mapping projects in ASALs, providing technical quality assurance on GIS and conducting/interpreting hydrological, geological, and geographical data.
• Experience working in Machakos County and proof of previous record of conducting a similar study will be an added advantage.
• Have the capacity to put together a professional team to carry out feasibility studies with similar complexity.
• The consultant should have excellent English writing/communication skills.
• Ability to mobilize all the required equipment/instruments at the required time and place
• Excellent presentation and report writing skills.

Must be registered by the Geological Registration Board and preferably an active member of the Geological Society of Kenya (GSK).