Manage what you measure: Better groundwater monitoring comes to West Africa

re-posted from BRAVE

by David MacDonald, British Geological Survey

A key component of water resource management is the sound scientific understanding of water flows and storage. Where water supplies are sourced through wells and boreholes in the underlying rocks, we need to understand the volumes of water stored there and how natural climate variability and land cover control how these stores are replenished.  For longer term planning purposes, we also need to assess how climate and land use change will impact on the resource.

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Monitoring groundwater levels at the Sanon catchment, Burkina Faso

The BRAVE project aims to provide tools to support water resource management in Ghana and Burkina Faso.  This is expected to improve our understanding of the water flows and storage through the instrumentation of a series of small catchments to monitor all aspects of the water balance.  The strategy for the BRAVE project was to build on existing monitored catchments, recognizing the cost of monitoring equipment; the time and effort required to build relationships with local communities in the catchments being monitored; and the value of existing contextual and longer-term data sets.

In Burkina Faso, one of the detailed monitoring catchment which BRAVE is working in is around the village of Sanon, 40 km to the north of the capital city, Ouagadougou. Sanon represents much of semi-arid West Africa as the land cover has been significantly changed through farming. The site was first established by BRGM, the French Geological Survey, but has been built up in recent years by the Institut International d’Ingénierie de l’Eau et de l’Environnement (2iE), with input from the Institut de Recherche pour le Développement (IRD). Prior to BRAVE’s involvement, there was a network of monitoring boreholes and a weather station in place, and geophysical surveys had been undertaken to characterise the hydrogeological setting. This, with the time series data collected, had allowed a conceptual model of groundwater flows and storage to be developed. Crucially, 2iE has developed a good relationship with the local community and involved members of the community in this monitoring.

Through the BRAVE project, the further development of the monitoring network at Sanon has been a collaborative activity involving 2iE, the University of Ouagadougou (UO1), IRC Burkina Faso and the British Geological Survey. This has included the drilling and testing of additional boreholes, enhancement of the weather station, installation of a series of transects of access tubes to measure soil moisture and the setting up of a river flow measurement site. It has also involved the construction of three plots (4 x 20 m) containing land use representative of the catchment within which runoff, soil moisture, groundwater level, soil infiltration, soil evaporation and plant growth and transpiration are directly measured. The monitoring is undertaken by members of the local community and by students from 2iE and UO1, as well as by BRAVE project staff.

The other two existing catchments where the BRAVE project has enhanced monitoring, are part of the network of research catchments run by the West African Science Service Centre on Climate Change and Adapted Land Use (WASCAL), a large-scale programme for strengthening research infrastructure and capacity involving ten West African countries and funded by the German government. One of these catchments, Aniabisi, is in Northern Ghana in an area similar to Sanon, where the landscape has been substantially changed through farming; the other, Nazinga, is just across the border in southern Burkina Faso in a nature reserve where the natural land cover is still intact. The infrastructure already in place in these WASCAL catchments has been built upon through collaboration by WASCAL, the Ghanaian Water Research Institute and BGS. Aniabisi now has infrastructure and monitoring equipment similar to that in Sanon, including the three land use plots; Nazinga is a scaled down version of this. As with Sanon, the local relationships with communities has been important in the installation of new infrastructure and local residents are also undertaking some of the monitoring work. Crucial impacts have been the support of WASCAL technical staff in the development and subsequent running of the sites.

The collaboration between BRAVE and West African organisations has been a great success that has seen the value added to established sites. The embedding of BRAVE research will greatly improve the chances that the monitoring sites developed through UPGro will be sustained beyond the period of the Programme. The importance of the resulting datasets cannot be underestimated, as we strive to understand the impacts of environmental change on the water resources that underpin future adaptation and resource management.

 

Top Photo: Sorghum cropping is a land use type that is included in monitoring plots at both Sanon and Aniabisi

Uncovering how groundwater is used, in Tanzania

re-posted from: Grofutures.org

The GroFutures team in Tanzania has just completed the data collection component of the Participatory Rural Appraisal (PRA) exercise in the Great Ruaha Basin of Tanzania. The team comprised Andrew Tarimo, Devotha Mosha Kilave, Gebregziabher Gebrehaweria and Imogen Bellwood-Howard. Following initial training at Sokoine University of Agriculture, the team moved to the study site in Mbarali District and worked in three villages (Matebete, Ubaruku and Nyeregete) between 23rd August and 2nd September 2017. During the PRA exercise the team carried out a range of activities including seasonal calendars development, long-term trend analyses, wealth indexes, technology rankings and a well inventory (see photos below).

The team documented a range of groundwater and other water use strategies involving dug wells, shallow and deep groundwater wells alongside surface water and natural springs. With the well inventory, the team was able to locate geographically groundwater sources within the study areas. The PRA exercises allowed the team to make qualitative characterisation of different water sources. Preliminary data include the observation that wealthier people were often beginning to invest in more expensive, private infrastructure. Quality was a concern as much as quantity, which was highly relevant in the light of recent health scares. A detailed analysis of the entire survey dataset is curently being carried out by the team.

Groundwater monitoring established in the Upper Great Ruaha Basin, Tanzania

Re-posted from GroFutures.org

The GroFutures team at Sokoine University of Agriculture (SUA, Tanzania), led by Japhet Kashaigili (SUA) with support from PhD students, Hezron Philipo (SUA) and David Seddon (UCL), established in July (2017) a groundwater-level monitoring network in the Upper Great Ruaha Basin Observatory in southern highlands of Tanzania.  This area is part of the Southern Agricultural Growth Corridor of Tanzania (SAGCOT) where increased use of groundwater and surface water is anticipated to support agricultural production.  Constructed monitoring wells at depths ranging from 18 to 32 m below ground were drilled using a PAT-DRILL 421 rig. The team also instrumented monitoring wells recently constructed by project partners at the Rufiji Basin Water Board (RBWB) in the Tanzanian Ministry of Water and Irrigation.

The new monitoring network comprises an upstream location at Chimala at the base of an escarpment and a downstream location at Mbarali within the alluvial plain. A monitoring well at Chimala Secondary School was installed into coarse unconsolidated sands and gravels to a depth of 26 m. This monitoring well is linked to both an additional monitoring well at Usangu Secondary School and a river gauge. Both monitoring wells are equipped with automated dataloggers providing hourly groundwater-level measurements. A third borehole was constructed at Chimala Primary School though no groundwater was encountered up to a depth of 30 m. At Mbarali, two monitoring wells were constructed on the St. Ann’s Secondary School and now form a transect of 4 monitoring wells as the team also instrumented two monitoring wells recently constructed by the RBWB at Rujewa at Mbarali Secondary School and Jangurutu Primary School.

The new infrastructure is expected to reveal for the first time the dynamics between groundwater and surface water in the Upper Great Ruaha sub-catchment of the Rufiji Basin and answer key questions around the nature of groundwater recharge and whether seasonal river flow recharges  groundwater or groundwater sustains river flow. Further work will also seek to ensure that this observatory is equipped with both tipping-bucket rain gauges to record sub-daily (hourly) rainfall intensities and soil-moisture probe arrays to better understand how intense rainfalls are transmitted through alluvial soils.

Ethiopian farmers and households have their say on their groundwater needs

re-posted from: Grofutures.org

The GroFutures team in Ethiopia has recently completed a survey of 400 households from predominantly agricultural communities within the Becho and Koka Plains of the Upper Awash Basin of Ethiopia; there are the same communities where the GroFutures team recently constructed and deployed new groundwater monitoring infrastructure. The team of social scientists, led by Yohannes Aberra of Addis Ababa University with support from Motuma Tolosa and Birhanu Maru, both from the Oromia Irrigation Development Authority, applied a questionnaire to poll respondent views on small-scale, household-level use of groundwater for irrigation, the status of groundwater governance, and their experiences of different irrigation, pump, conveyance and application technologies. The same questionnaire will be applied in other GroFutures basin observatories later this year.

The team began the household-level surveys on May 27th (2017) and completed 400 of these within 15 days. Two weeks prior to the start of the survey, the team reviewed the GroFutures-wide questionnaire to familiarize themselves with the questions and logistics of implementation. During implementation, the team encountered a major challenges in that many household heads were unavailable at their houses and had to be traced with all movements occurring in particularly hot weather.

In Becho, the team conducted questionnaires in the village of Alango Tulu whereas in Koka the team surveyed the village of Dungugi-Bekele.  As the total number of households does not exceed 600 in each village, the team’s polling of 200 households in each provided a high representative sample (>30%). The livelihoods of the polled village of Alango Tulu are dominated by local, household-level (small-scale) farming.  In the Dungugi-Bekele, the team focused on resident farmers though it was recognised that there are many irrigators who rent and cultivate land but don’t reside in the village.

The results of these questionnaires are eagerly awaited by the whole GroFutures team. A small sample of 30 questionnaires will be reviewed immediately by fellow GroFutures team members, Gebrehaweria Gebregziabher (IWMI) and Imogen Bellwood-Howard (IDS), and the Tanzanian colleagues (Andrew Tarimo and Devotha Mosha-Kilave) as they prepare shortly to trial the same questionnaire in the Great Ruaha Basin Observatory.

Photos: GroFutures social science team of the Upper Awash Basin in Ethiopia conducting household questionnaire survey in rural communities within the Becho and Koka Plains (GroFutures research team)

Ethiopia Phase 2 – Survey Update

Phase 2 of the Hidden Crisis fieldwork is underway – right on schedule. The work has started in Ejere, a Woreda about 100 km north of Addis in Ethiopia. In this major survey of 50 poorly functioning rural waterpoints, we spend two days dismantling and testing each water point to work out what the main […]

via Ethiopia Phase 2 – Survey Update — UPGro: Hidden Crisis

Uganda lift off!

The physical sciences longitudinal studies have kicked off in Uganda this week. The aim of these longitudinal studies is to capture the time-based hydroclimatic and hydrogeological processes of the groundwater system at selected hand pumped boreholes (HPBs). These temporal datasets provide valuable information to understanding HPB functionality that could not be addressed from the two […]

via UpGro Hidden Crisis Physical Sciences Longitudinal Studies – Uganda Lift Off! — UPGro: Hidden Crisis

Looking back: 2016 Kenya fieldwork

from Gro for Good newsletter 2

A comprehensive and efficient environmental monitoring network has been set up for the study area collecting relevant, timely and cost-effective data on rainfall, river flow and groundwater level and recharge. Data will be used in the development and running of a Groundwater Risk Management Tool, which will include a hydrogeological model. The model will be able to simulate and predict the effects of different levels of extraction and rainfall on the system, helping Kwale County to make plans to ensure that it has a good and sustainable water supply for people and industry.

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The project is making use of data on temperature, rainfall, humidity, air pressure, wind speed and direction from a number of automatic weather stations (AWS) installed in the project region. Much of the instrumentation has been provided by the Trans-African Hydro Meteorological Observatory (TAHMO) project, hosted in this region by Kenya Meteorological Services.

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River Flow Monitoring and Measurement

To understand the amount of water available in rivers and dams in the study area, various water level and discharge monitors have been installed. In particular, streamflow on the Mukurumudzi and Ramisi Rivers is being monitored to determine the water balance of the rivers at different points, enabling the researchers to understand and model groundwater inputs along these water courses.

River monitoring has been a great example of cooperation between project partners. As well as the existing staff gauge used by WRMA and Base Titanium to monitor flow in the Mukurumudzi River, the project has installed automatic water level loggers (Heron Logger) at two locations on the Mukurumudzi ((3KD06 – Shimba Hills – upstream and Irrigation Intake Works near Bomani Shopping Centre – downstream) and one on the Ramisi River at Eshu Bridge. These are complemented with manual staff gauges provided by WRMA Sub-regional Office in Mombasa. The instruments and staff gauges were installed jointly with WRMA/WRUA, Base Titanium, KENHA and the community. Flow in Ramisi River used to be monitored at Mwachande Bridge (3KD01) stage gauge by WRMA but the gauge has been vandalized and is not in operation.

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River Cross Section and Topographical Survey

A topographical survey was carried out at the river flow monitoring points at the Irrigation Intake Works (on the Mukurumudzi River) and at Eshu Bridge (on the Ramisi River) and measurements of cross section of the river were taken.

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The information will be used to facilitate flow measurement and permit the researchers to develop a Flow Rating Equation and Curve for each site, a key element of the hydrological model.

Surveyors and Survey Equipment at Eshu Bridge during cross section and topographical survey, May 2016 Cross-section of 3KD06 Weir on Mukurumudzi River, Shimba Hills. The figure below is the result of the river cross-section survey at the weir where water
flow is monitored and estimated for the Mukurumudzi River (by Base Titanium, WRMA
and Gro for Good) to aid water resources planning and decision-making. The weir structure also enables the consented abstraction of water by Shimba Hills Community Water Supply project which provides water to Shimba Hills shopping centre and its environs.

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Groundwater hydrochemistry

The chemical composition of groundwater provides useful information about the flow of water into and through the underground aquifers. Chemical and biochemical analysis also allow us to monitor substances which affect the safety and taste of drinking water. Three groundwater sampling campaigns have now been completed, involving the collection and analysis of water from open wells, rivers, handpumps and deep boreholes.

The first campaign was in September 2015 (wet season after the short rains; 81 sampling sites), the second was in March 2016 (dry season, fewer points sampled due to some wells/boreholes being dry) and the final sampling campaign in June 2016 at the end of the wet season (long rains), thus providing information about seasonal variation in water quality and on the process by which the aquifers are recharged following rain. A total of 43 groundwater sites are under fortnightly monitoring for groundwater static level, pH, temperature and conductivity.

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Sample pH, electrical conductivity, temperature, dissolved oxygen and redox potential (ORP) were measured during fieldwork using a flow cell so that the water did not come into contact with air. Other parameters analysed in situ were alkalinity, ammonia levels and faecal bacteria. Samples were also taken to Spain for laboratory analysis to indicate major ions, trace metals, water isotopes (deuterium and oxygen 18) and Total Organic Carbon.

Only very few points contained ammonia, nitrates or trace metals. However, most of the open wells contained high levels of faecal bacteria. The results will be explained in detail in the next newsletter.

Geophysics

by Julius Odida, PhD candidate, University of Nairobi

Geophysical methods (ground-based physical sensing techniques) are used to provide information about sub surface geology. The Gro for GooD project is using both electrical resistivity tomography (ERT) and vertical electric sounding (VES) to identify and characterize the aquifers (water-saturated sub-surface rocks) which lie beneath Kwale County. Over the past year, a number of geophysical surveys have been conducted by a team from University of Nairobi, WRMA and Rural Focus Ltd. The study involved four phases: planning/desktop studies, reconnaissance, actual data acquisition and report writing. Lower resistivity may indicate water saturation and/or fracture zones in the rock. We present a preliminary interpretation of some results below.

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Field update from Kenya

by Prof. Dan Olago, University of Nairobi in Gro for Good newsletter 2 2016

Welcome to the second edition of our project newsletter. There has been a lot of activity in recent months including: the completion of the installation and commissioning of the climate and hydrological monitoring network; two groundwater sampling campaigns in March and June; geophysical surveys to define the aquifer geometry and structure using both electrical resistivity tomography (ERT) and vertical electric sounding (VES) approaches; an anthropological survey related to determinants of use/non-use of the shallow wells installed with smart hand-pumps; compilation of a list of data sets for the project; and stakeholder engagement, both within the county and with stakeholders such as the Kenya Meteorological Department (KMD) and Water Resources Management Authority (WRMA) at the national level. I will, however, here focus on the geophysical surveys.

The project team has been collaborating with WRMA personnel in carrying out the geophysical survey. The WRMA kindly made its ABEM SAS1000 Terrameter available to enable this exercise to proceed. The ERT surveys which were carried out in three phases in December 2015, January 2016 and May 2016 are now completed. The VES survey which started in mid July will be completed in early August. The main aim of the geophysical survey is to get a better handle on the aquifer geometry and structure, with a focus on where geological understanding is poor, and to delineate the shallow and deep groundwater systems. The outcomes of this activity will provide critical inputs to the hydrogeological flow model that is already under development. This model will be integrated into the groundwater risk management tool to promote improved groundwater governance balancing economic growth, groundwater sustainability and poverty reduction, and taking into account the competing demands for domestic, agricultural and industrial uses of the resource.

The fieldwork has not been without incident; some unknown person cut off and went away with about 70m of cable and this slowed down the working pace, and we had to take on more local personnel to guard the cable layout to avoid any further losses. Heavy rains at times also meant that work had to be delayed or stopped altogether on some days. Overall, these incidents notwithstanding, it has been a great team building experience. The daily interaction between the team members fostered valuable knowledge exchanges and lifelong skills enhancement in geophysical surveying.

Finalising Obed’s fieldwork in Dodowa

By:  Obed Minkah

Final fieldwork activities in Dodowa included the establishment of monitoring network which consist of 40 wells to monitor groundwater fluctuation and to help us determine the groundwater flow direction. In order to know the groundwater flow direction, the monitoring wells were levelled to each other using a total station. It was daunting task to level wells scattered on about a 13.5kmsq area but the task was done within 3 days with support from my colleagues (Isaac and Eric) from The Hydrological Services Department. The water levels of these wells were also measured weekly to know the groundwater levels change over time and from the monitoring it was observed that water levels in the wells were decreasing gradually over the course of fieldwork.

 

Obed working during the levelling of the monitoring wells
Continue reading Finalising Obed’s fieldwork in Dodowa

Water quality is interesting!

By: Carlos Enrique Aponte Rivero on T-group.science

Yes! It is very interesting for these kids, obviously amazed by the strange equipment put into the water. As soon as I started to set up the probes and to do the water quality measurements, I was suddenly surrounded by children, getting closer and closer trying to find out what is this about. It was in Osunyai Street, where I took a sample from a borehole close to Sombetini Primary School. The children are students of this school and they were just walking around when I arrived to continue with my data collection. The T-GroUP Project gave me the opportunity to mix my technical background in chemistry and water quality with social science, an exciting challenge with an interesting experience working in the field.

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Continue reading Water quality is interesting!