The Kakuma Refugee Camp is located in the semi-arid Turkana County of Northwestern Kenya. The Camp was home to 184,966 refugees (reliefweb, 11 Jan, 2016) at the time of our survey. Kakuma is entirely dependent for drinking water on groundwater pumped from 12 wells. Drilling success is variable. Usually, successful wells with significant yields (> 5 m3/hour) are completed in close proximity to the Laga Tarach river bed. As one moves further from the ephemeral river, drilling success is sporadic with dry holes and brackish groundwater being common. High naturally occurring fluoride concentrations occur in all wells. From January 10 through January 22, 2016, a geophysical water exploration program primarily funded by the Society of Exploration Geophysicists (SEG) Geoscientists Without Borders Program (GWB) was carried out in the Kakuma Refugee Camp and nearby areas. The overall goals of this program included providing drilling targets for new water wells, introducing an improved geophysical approach to water exploration, training of refugees and Kakuma WASH (Water, Sanitation, and Hygiene) staff, and adding to the knowledge of the hydrogeology of the area.
ERT (electrical resistivity tomography) was used to differentiate granular overburden from clay, weathered rock from fractured rock, fresh water from saline water, and to delineate faults. Seismic refraction clearly delineated the top of rock. The combination of ERT and seismic refraction are a vast improvement over the typically run one dimensional (1-D) vertical electrical soundings (VES) which assume perfectly flat lying geology. Nevertheless, confident identification of high production, low salinity and low fluoride aquifers is challenging. The results of this program revealed the geology and hydrogeology of Kakuma and Kalobeyei to be far more complex than previously believed. Nevertheless, in May 2016, two months after the completion of the geophysical program, three high yielding wells testing at sustainable yields of 29 m3/hr, 40 m3/hr, and 45 m3/hr were drilled and completed in what we have termed the Northern Well Field. Given UNHCR’s (United Nations High Commissioner for Refugees) practice of pumping wells for 10 hours per day, with a target water supply of 20 litres per person per day, these first three wells can provide water to 57,000 refugees. Water chemistry analysed from the only one of these wells drilled directly on a geophysical section indicates low salinity and a low fluoride concentration.
Generally, water exploration methods in East Africa have changed little since the 1960s. This program demonstrates that modern approaches can result in significantly improved water well drilling success rates, improved water quality, and a dramatically improved overall understanding of the geology and hydrogeology of a given area.
Introduction to Kakuma and Kalobeyei
The Kakuma Refugee Camp is located in the Turkana Desert of northwestern Kenya (Figure 1), at an elevation of approximately 600 m above mean sea level (amsl). The Camp is jointly managed by the Office of the United Nations High Commissioner for Refugees (UNHCR) and the Kenyan Government. The Camp was originally opened in 1992 to receive the “Lost Boys of Sudan,” who were refugees from the Second Sudanese Civil War, which ended in 2005. The plight and flight of the Lost Boys of Sudan has been the subject of many popular books and movies including "What is the What", by Dave Eggers, and "The Good Lie", starring Kakuma refugees and with Reese Witherspoon. The Camp (Figure 2), which presently provides asylum to about 163,000 refugees (Data.UNHCR.org) from about 16 countries in East Africa, was designed for a maximum Camp population of 100,000. After the declaration of a new state in South Sudan in 2013, it was hoped that the Sudanese population of the Camp would be repatriated. However, ensuing conflict in South Sudan resulted in more than 46,000 Nuer and Dinka refugees coming to Kakuma since December, 2013. As well, the Camp continues to host refugees from other countries who are fleeing from famine, drought, “cattle wars,” political turmoil, and other conflicts in East Africa.
The Camp is divided into four residential sections (Figure 3), with Kakuma 1 being the original area where the Lost Boys settled, and Kakuma 4 being the living area of the most recent arrivals. As of January 2016, UNHCR was preparing to receive an additional 60,000 refugees (UNHCR.org/ke), more than doubling the initial design capacity of the Camp. The plan is for many of these new arrivals to live in a newly constructed Camp about 20 kilometres west of Kakuma, called Kalobeyei (Figure 4). Kalobeyei will be unique among presently operating UNHCR camps in that residents will be encouraged to practice agriculture rather than to simply rely on UNHCR rations. In addition, significant interaction with the host community (i.e. the semi-nomadic Turkana) will be facilitated rather than avoided.
Turkana County is Kenya’s largest county, with an area of about 71,598 km2, and a population of 855,399 (2009), both statistics being very similar to those of the Canadian Province of New Brunswick. The climate and landscape of Kakuma is semi-arid, essentially desert (Figure 5). The average annual temperature in Kakuma is 28°C, with temperatures very rarely dropping below 21°C. Annual precipitation averages 32 cm, the same as Calgary’s average yearly rainfall (Global News, 2016). Most precipitation in Kakuma falls as a few intense rain events in April and November (Figure 6).
Geological and Hydrogeological Setting
Kakuma is located in the northwestern extent of the Kenyan Rift. The Kenyan Rift is the eastern branch of a much larger feature, the East African Rift System. The most pronounced geographic feature of the Kenyan Rift is the broad valley of the Turkana depression and Lake Turkana lying on the axis of the Kenyan Rift (Morley et al. 1999).
The area around Kakuma is called the Lotikipi Plains. Sottas (2013) describes the Lotikipi Plains as a saucer-shaped depression bordered to the east and west by volcanic ranges. The “saucer” itself is filled with volcanic derived, fluvial sediments from Middle Miocene (5.5 Ma) to present, reaching a maximum thickness of 300 m. Underlying the sediments are Middle to Early Miocene (5.5 23.7 Ma) rhyolites, then Oligocene age (23.7–36.6 Ma) basalts underlain by sub-volcanic sedimentary rocks of Paleocene to Cretaceous age (57.8–144 Ma), and finally Precambrian basement consisting mainly of gneisses and schists. The Lotikipi Basin is heavily faulted in a horst and graben structure.
As the Kakuma Refugee Camp is on the southern edge of the Lotikipi Basin, numerous rhyolite outcrops occur in the exploration area. Available drilling data indicate that the sediment overburden in Kakuma reaches a maximum of approximately 40 m in thickness. Generally, underlying the overburden, various drilling campaigns encountered volcanic rock, though sedimentary and igneous rock has also been encountered. The possible interfingering of volcanic rock and unconsolidated sediment require that one use the term “bedrock” with caution.
Presently, groundwater is the only available water source for the Kakuma Refugee Camp and the surrounding area. The vast majority of successful water wells drilled in Turkana County are located along the lagas (wadis, UNICEF 2006). Kakuma is no exception, as the estimated 15 wells that are presently pumping are all located in, or in close proximity to Laga Tarach (Figure 7), which flows perhaps a few days each year. Sottas (2013), as well as available drilling data, suggests that both the overlying sediments and underlying, weathered (or fractured) rock serve as aquifers. The common practice of screening (i.e. installing slotted pipe for water intake and filtering sediment) over multiple aquifers (rather than the preferred practice of screening a single aquifer), and interconnecting screened intervals with permeable backfill material, make it very difficult to determine the relative contribution of the bedrock aquifer versus the overburden sediment aquifer. In addition, drilling information from abandoned boreholes is rarely archived, and information that is archived is often confusing or contradictory. Sottas concluded that most boreholes draw from both the volcanic rock and overburden alluvial aquifers.
The shallow, alluvial aquifer is generally associated with higher yields and greater storage, with lower fluoride concentrations, but with greater vulnerability to bacterial contamination. The deeper volcanic rock aquifer is associated with lower yields, high naturally occurring fluoride concentrations, and lower vulnerability to bacterial contamination. Many water wells in the area are brackish. Increasing salinity in water wells has been observed during prolonged periods of drought (UNHCR, personal communication). As no borehole geophysical information is available, and a general practice in East Africa is the screening of any and all zones of water production, more confident and detailed descriptions of the water quality of the individual aquifer systems is challenging.
The main geochemical constraints on water potability are elevated salinities and elevated fluoride concentrations. Elevated fluoride concentrations in groundwater are common in rift valley environments (Essentials of Medical Geology, 2005). Sottas concluded that the high concentrations of fluoride are likely associated with the weathered volcanic rock aquifer system. Of the 15 Kakuma pumping wells tested in July of 2016, fluoride concentrations ranged from 1.5 mg/l to 8.4 mg/l. Milnes (UNHCR, personal communication) has observed that fluoride concentrations often rise with increasing salinity. Milnes has suggested that where both the alluvial and volcanic aquifers are screened (i.e., producing water), dropping water levels in the alluvial aquifer, and an increasing contribution from the volcanic aquifer will result in an increasing fluoride and salt concentration.
Aquifer recharge at the Kakuma Refugee Camp is likely associated with direct recharge from Wadi Tarach during flooding events (i.e. the laga fills in flash floods, and aquifers are recharged from the lagas). Rainwater acts as a secondary but direct source of recharge.
Very little area specific information is available regarding our Kalobeyei exploration area, located 30 km to the west of Kakuma. The report Hydrogeological and Geophysical Investigations, Kalobeyei (2015) describes the geology and hydrogeology of the Kalobeyei area as being very similar to Kakuma, with clayey alluvium overlying Tertiary lavas, with sand lenses being present in proximity to the major lagas. Gicheruh suspected that weathered rhyolites underlay most areas of alluvium. Underlying the Tertiary, rhyolitic lavas, are interbedded basalts and sedimentary rocks, and Precambrian basement.
1-D resistivity soundings and water “witching” have been used extensively in Turkana County (Oxfam Gb, 2009), including in the Kakuma Refugee Camp and in Kalobeyei (Gicheruh, 2015), as part of earlier and ongoing water exploration programs. The nature of the Rift Valley geology, as well as the results presented here, indicate the geology and hydrogeology are far too complex and variable to be addressed by 1 D geoelectrical methods. Past efforts by other researchers to use ERT (Sottas, 2013) in Kakuma had concluded that the results were uninterpretable. In reviewing previously collected resistivity sections, we concluded that collecting companion seismic refraction data would likely provide unambiguous delineation of the top of rock. The interpretation of earlier resistivity surveys likely suffered from an ambiguity of an electrical properties contrast between overburden lithologies and underlying volcanic rock exhibiting various degrees of weathering. Additionally, given what we now know, earlier surveys failed to investigate deep enough and over enough line length to recognize variability within both the bedrock and the overburden, that is, to see the proverbial “forest through the trees.” Despite shortcomings of previous 1-D and two-dimensional (2-D) geoelectrical surveys, this program tremendously benefitted from results compiled in available reports and studies.
Both past and these current surface geophysical surveys were handicapped by a complete absence of borehole geophysical data. Borehole geophysical data has been of great value in previous geoelectrical water exploration programs in East Africa (Kellett and Bauman, 2004). Unlike most of East Africa, existing water wells in Kakuma were completed with steel casings, eliminating the possibility of carrying out borehole induction conductivity logging.
ERT is a technique for mapping the distribution of subsurface electrical resistivity in cross-section (Figure 8). The main objectives of the ERT survey were to identify resistive, fresh water saturated sands and gravels. Resistivity data are collected through a linear array of electrodes coupled to a direct current (DC) resistivity transmitter and receiver, and an electronic switching box. The spacing between electrodes largely controls the horizontal and vertical resolution of the data (smaller spacing results in higher horizontal and vertical resolution). Similarly, the length of the array controls the depth of investigation (longer arrays yield greater investigation depths). Data collection is carried out in a sequential and automated fashion that takes advantage of all possible combinations of current injection and potential measurement electrodes. Data were modeled as 2-D geoelectric sections with 2-D finite difference or finite element inversion software (Loke and Barker, 1996). In this program, electrode spacings varied from 5 m to 10 m, with corresponding depths of investigation varying from 70 metres below ground surface (mbgs) to 140 mbgs. Line lengths varied from 400 m to 1600 m. 16 ERT sections were collected for a total of 11.4 km of line. The Schlumberger gradient array was used for current injection and voltage measurements as this array is a good compromise of optimizing both horizontal and vertical resolution, and can take advantage of the multichannel ABEM LS receiver.
The main objective of the seismic refraction survey was to confidently delineate the top of rock, as even weathered volcanic rock will typically have significantly faster compressional wave (P-wave) velocity than overburden materials. The seismic refraction survey mainly utilized an elastic weight drop with a 40 kg beam (PEG-40) as a compressional wave source (Figure 9), though a 16 pound sledge hammer was used in areas without vehicle access. All lines were shot with 40 Hz vertical component geophones, with a single geophone in each group, and with a 5 m geophone spacing. Geometrics Geode 24-channel networked seismographs were used for all surveys. Most lines were shot with 144 channels (6 networked seismographs), though some lines used fewer channels due to space constraints. Ten seismic refraction lines were collected for a total of 5.8 km of line length. Individual sections ranged in length from 355 m to 720 m. The P-wave velocity models were solved using seismic inversion software.
The geophysical field program was executed over the period from January 10 through January 22, 2016. Field work was carried out by ERT and seismic refraction crews working simultaneously, usually in different areas separated by several kilometres. All positioning was carried out with Trimble Geo7X Handheld GPS units and a base station.
For organizational purposes of discussion, the investigation areas have been grouped into five arbitrarily named areas (Figures 10 and 11):
- Laga Tarach South;
- Northern Well Field;
- Central Well Field;
- West of Kakuma 1; and
Laga Tarach South is an area with some borehole control, has wells of variable yield and water quality, and is in, or close to the main channel of Laga Tarach. Laga Tarach South is immediately south and east of the longest inhabited (since 1992) portion of Kakuma 1. Survey objectives here included overall testing of the survey approach, and locating potential drilling sites with possible superior yields and lower fluoride concentrations, as compared to existing wells.
The Northern Well Field is the area of the highest yielding wells, has some borehole control, and is also close to Laga Tarach, which likely functions as the primary source of groundwater recharge (Sottas, 2013). The Northern Well Field is of particular interest as its location makes it a possible source of water for both Kalobeyei and Kakuma, as well as for local Turkana villages and family compounds in the immediate surroundings. Survey objectives here included locating potential drilling sites with possible superior yields and lower fluoride concentrations as compared to existing wells.
The Central Well Field is approximately midway between Laga Tarach South and The Northern Well Field, and is also in close proximity to Laga Tarach. There are a number of wells in this area; however, well control is poor as most wells are hand dug or have very limited accompanying geological and hydrogeological descriptions. The Central Well Field is on the northern edge of densely populated Kakuma 1. Survey objectives here included locating potential drilling sites with superior yields.
The area West of Kakuma 1 has no producing water wells. However, numerous abandoned wells have been drilled in this area, including the “Kakuma 1 VES 1 Borehole” which tested at 110 m3/hr, though with elevated salinity and a very high fluoride concentration. Limited geologic control exists in this area due to an absence of available archived information. The high tested yield from the noted borehole makes this an interesting area for exploration. Also, as there are no producing wells in this area, a successful water well in the area West of Kakuma 1 would bring a water source considerably closer to the settlements of Kakuma 3 and 4, and possibly avoid water delivery disruptions during flooding in the lagas. (Buried pipelines are often damaged by flood waters.)
The Kalobeyei area has only a single producing water well which has been tested at 5 m3/hr. The surficial geology appears considerably different in the Kalobeyei exploration area as compared to Kakuma, as in Kalobeyei there is considerable rock outcrop, and the nearby lagas are much smaller than Laga Tarach. Exploration in the Kalobeyei area occurred in proximity to the existing Kalobeyei borehole, and in three small lagas near the proposed new Kalobeyei Refugee Camp, lagas Elelia, Esikiriait, and Kangura.
Field Based Physical Properties Observations
Though limited, all available borehole data were used for correlation purposes. Water chemistry information is of uncertain value, as most existing water wells are screened across multiple zones, spanning both overburden and bedrock aquifers. No borehole geophysical logs exist. Interpretations of physical properties were made through a combination of well ties to the resistivity and P-wave velocity sections, and some interpretive assumptions of measured physical properties. Physical property interpretations included:
- depth to competent bedrock, as derived from the P-wave refraction results, generally correlates with the 2000 m/s velocity contour;
- the delineation of more massive bedrock with lower groundwater yield potential, is based on relatively higher bedrock resistivities (greater than approximately 60 ohm-m);
- the delineation of fractured to highly weathered bedrock with higher groundwater yield potential, is based on relatively lower bedrock resistivities (less than approximately 60 ohm-m);
- saline and/or clay overburden, is based on very low resistivities (less than approximately 10 ohm-m);
- fresh water saturated or partially saturated granular overburden is interpreted as being between approximately 30 ohm-m and 100 ohm-m;
- saturated overburden, with a significant percentage of clays or elevated salinity, is between 10 and 20 ohm-m;
- saturated saprolite (very highly weathered bedrock) is between 10 ohm-m and 30 ohm-m; and
- granular, dry overburden is greater than 100 ohm-m.
Field Results and Interpretations by Investigation Area
On its most practical level, this geophysical program was designed to site new water wells. As such, a table of possible drilling targets in each of the five investigation areas was delivered to UNHCR as part of the project reporting. This table included the investigation area, the referenced geophysical surveys, georeferenced coordinates (in both UTM and latitude/longitude), and the interpreted nature of the targeted aquifers. This latter category included thick, saturated, granular alluvial overburden; weathered volcanic rocks; fault blocks; and fractured rock in proximity to faults. As well, zones of high salinity, thick clays, unsaturated overburden, massive bedrock, very shallow bedrock, and intensively weathered volcanics were noted as to be avoided.
In Laga Tarach South, potential aquifers included areas of thicker overburden and weathered rock. Of note is that the original UNHCR Borehole drilled in this area is the only Kakuma well screened entirely in bedrock. The fluoride concentration in the UNHCR Borehole is 8 mg/l (UNHCR, 2014), more than five times the World Health Organization (WHO) and Kenyan drinking water guideline, and greater than the 4 mg/l concentration above which skeletal fluorosis is believed to occur (Essentials of Medical Geology, 2005).
In the Northern Well Field, resistivity and P-wave velocity sections, supported by ties to existing water wells, clearly delineated thick, laterally extensive, saturated sands and gravels (Figure 12). Extensive zones of weathered bedrock were also interpreted. However, the extensive granular aquifer, as well as the close proximity of the Northern Well Field to Laga Tarach, a source of secondary recharge, elevated this area as being highly prospective for further exploration and development.
The hydrostratigraphy of the Central Well Field is difficult to confidently determine as all existing water wells are either poorly documented, or are screened across multiple zones, spanning overburden and bedrock. Zones of thick, saturated granular material are present (Figure 13), along with extensive zones of likely weathered volcanics. The possibility of increasing the groundwater yields of numerous hand dug wells in this area is likely very limited due to a geophysically interpreted underlying, shallow aquitard.
The survey area West of Kakuma 1 is highly prospective for high groundwater yields. At 90 mbgs, P wave velocities indicate that competent rock is deeper here than anywhere else in either Kakuma or Kalobeyei. While no completed wells exist in this area, drilling records of an abandoned well show tested yields of 110 m3/hr, sediments to 66 mbgs, and a contact of sedimentary rock overlying volcanics at 84 mbgs. The well was abandoned due to high salinity (4377 mg/l) and very high fluoride concentrations of 10.2 mg/l. However, drilling records indicate that elevated salinities were encountered at a depth of 78 mbgs. Carefully monitored drilling, accompanying borehole geophysical logging, and well construction specifically screening low salinity aquifers could result in a high yielding well in this strategically important area.
In the investigation area of Kalobeyei, in lagas Elelia and Esikiriait, the ERT and seismic refraction surveys, along with visual observation of outcrop, clearly indicate saline or clayey overburden overlying shallow bedrock (Figure 14). West of these lagas, in Laga Kangura and in proximity to the only existing well in the area (Kalobeyei Well, tested yield of 5 m3/hr from Gicheruh, 2015), four ERT sections spectacularly imaged at least two, and possibly three steeply dipping, but electrically conductive faults (Figure 15). Seismic refraction data indicate bedrock is very shallow. Drilling targets have been suggested in close proximity to the faults where rock is predicted to be fractured (Figure 16), and on the flank of the faults closest to lagas where possible fractured rock aquifers could benefit from secondary recharge during flood events.
Given the laterally extensive, saturated sands geophysically mapped in the Northern Well Field, the results and interpretations of this 2016 geophysical program were used to site Borehole 13 (525 m along line ERT7) in May, 2016 (UNHCR, personal communication; see Figure 12). A relatively shallow well was screened through sand to a depth of 28 m, avoiding the weathered volcanic aquifer seismically delineated at a depth of 30 m. Borehole 13 tested for a sustainable yield of 40 m3/hr, a fluid conductivity of 592 uS/cm (about 380 mg/l) and a fluoride concentration of 0.9 mg/l (well below the WHO and Kenyan drinking water guideline of 1.5 mg/l). The water chemistry from Borehole 13 strongly supports the hypothesis that elevated fluoride concentrations are largely associated with the weathered volcanic aquifer. UNHCR drilled two additional wells in the northward extension of the Northern Well Field. These two wells tested for sustainable yields of 29 m3/hr and 45 m3/hr (UNHCR 2017). As of March 2017, a 13 km pipeline will have been completed between these boreholes and the Kalobeyei refugee settlement, which will be capable of delivering approximately 1,200,000 litres of water per day to the refugees and local Turkana living there. There are currently 22,000 refugees settled in the Kalobeyei refugee settlement, with plans to expand that to 60,000 people, all of whom will be dependent on the water from these boreholes (UNHCR Operational Update 2017). This geophysical program has delineated other thick, alluvial, likely low fluoride and high productivity aquifers, with West of Kakuma 1 being the most notable.
In contrast, previous to this 2016 (UNHCR Water Well Data, February 2015) exploration program, sustainable yield tests had been carried out on 20 producing wells in Kakuma and Kalobeyei; the average tested yield of these 20 wells was 22 m3/hr. Only one of those wells tested for a yield of greater than 40 m3/hr. Also noteworthy is that many dry, brackish, low productivity, or very high fluoride concentration wells were drilled in the process of completing the existing successful wells. Besides improving the drilling success rate, the combination of electrical resistivity tomography and seismic refraction has given a much improved overall understanding of the hydrostratigraphy in both Kakuma and in the Kalobeyei area. In Kakuma, 2-D imaging is essential to interpret the rapidly changing spatial distribution of salinity, bedrock relief, interfingering volcanic and sediment contacts, and the precise lateral extent of important alluvial laga (i.e. wadi) deposits. In the newly developing Kalobeyei area, seismic refraction has shown that the area intended to house 60,000 refugees and 23,000 (UNHCR.org/ke) host community Turkana may be significantly more challenged for water resources than previously understood due to very shallow bedrock. Meanwhile, ERT surveys in Kalobeyei have identified extensive areas of high salinity, along with a number of well-defined faults that may be the most prospective drilling targets.
Improved geophysical programs will improve drilling success rates. Also of note, improved geological observations during drilling, borehole geophysical logging of PVC cased wells, screening and hydraulic isolation of selective aquifers, maximizing information from abandoned wells, improved archiving of data, reliable hydrochemical sampling, and installing dedicated monitoring wells will all greatly assist in interpreting surface geophysical data. 25 years after the Lost Boys of Sudan walked to Kenya, water exploration in such water-stressed areas, like Kakuma, would benefit by being carried out in a methodical rather than in the more haphazard manner that typically characterizes the early stages of water supply in a crisis situation. While more sophisticated exploration programs will also be more costly than 1-D vertical electric soundings and water witching, resulting improved drilling success rates can provide compensating budgetary benefits.
This program was funded largely by the Society of Exploration Geophysicists (SEG) Geoscientists Without Borders Program (GWB). UNHCR provided access to the Camp, access to their groundwater data base, and direction toward the issues of concern. Administrative and logistical support for this survey was provided by the small NGO IsraAID, whose mission statement is “…helping people all over the world overcome extreme crises….” Dr. Ellen Milnes, from UNHCR and the University of Neuchatel, provided a very helpful content review of this paper. All of the geophysical equipment and equipment repairs were provided for this program, at no cost to the program, by Paul Bauman Geophysics Ltd. The Canadian geophysicists below received no remuneration for their services, and participated in this field portion of this project during their “vacation” time. The field program was carried out by six geophysicists from Advisian WorleyParsons. Advisian WorleyParsons staff included Paul Bauman, Erin Ernst, Doug MacLean, Colin Miazga, Randy Shinduke, and Landon Woods. Franklin Koch, who was also a student intern at Advisian WorleyParsons, participated from the University of Calgary. Dr. Alastair McClymont, from Advisian WorleyParsons, assisted in planning and data processing. The field crew was staffed by 28 refugee and Turkana students from the IsraAID water and sanitation training program. The refugee and Turkana field crew received remuneration to the full extent as allowed by UNHCR’s work incentive payments.
About the Author(s)
Paul Bauman is the Technical Director of the Geophysics group at Advisian WorleyParsons. He has more than 30 years of experience in near surface geophysical exploration for groundwater, natural resources, tunnels, unexploded bombs, industrial waste, ancient burials, and essentially anything that someone may want to find without drilling or digging. Paul has applied creative geophysical solutions to challenging groundwater situations in remote locations over much of his career, including in Africa, Central America, Southeast Asia, and at home in Canada.
Erin Ernst completed a B.Sc. in Geophysics and a M.Sc. in Hydrogeophysics at the University of Calgary. While working at Advisian, she has travelled all over Canada, experienced untouched wilderness, cooperation with Canada’s First Nations, helicopters, the oil sands, and countless other unique places and circumstances.
Landon Woods has been working with the Advisian (a WorleyParsons Group) geophysics team for the past seven years. Field work has taken him across the globe, including Madagascar, New Zealand, Israel, and Kenya. Landon completed a B.Sc. in Geology at the University of Calgary (U of C), focusing on hydrogeology and near-surface geophysics, and is currently undertaking a M.Sc. concentrating in hydrogeology at the U of C.
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Oxfam Gb, September, 2009. Hydrogeological Survey Report: Groundwater Resources Investigations In Turkana South (Rift Valley Catchment Area). Prepared for Lopur Water Project at Lopur. Ref. No. WDG/497C-09/el, 23 pp.
Sottas, Jonathan, 2013. Hydrogeological Study of the Aquifer System of Kakuma, Kenya. Master Graduation Thesis Universite de Neuchatel. June, 2013. 106 pp.
UNHCR, 2016. Kenya Kakuma Operational Update, 01 – 15 March 2016. https://reliefweb.int/report/kenya/unhcr-kenya-kakuma-operational-update-1-15-march-2016
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Kambi ya Wakimbizi ya Kakuma iko katika Kaunti ya Turkana ya kaskazini magharibi mwa Kenya. Kambi hiyo ilikuwa na wakimbizi 184,966 (reliefweb, 11 Januari 2016) wakati wa uchunguzi wetu. Wakulima wa Kakuma wanahitaji maji ya chini ya ardhi kutoka visima 12 ili kupata maji ya kunywa. Mafanikio ya kuchimba visima hutofautiana. Kwa kawaida, visima vyenye mafanikio na mavuno makubwa (> 5 m3 kwa saa) hufanywa karibu na kitanda cha mto Laga Tarach. Unapotembea mbali na mto huo usio na muda, mafanikio ya kuchimba madini ni ya mara kwa mara kwa kuwa mashimo kavu na maji ya chini ya ardhi yenye chumvi ni ya kawaida. Kiasi cha juu cha fluoride kinachotokea kiasili hutokea katika visima vyote. Tangu Januari 10, 2016 hadi Januari 22, 2016, programu ya utafutaji wa maji ya kijiografia, iliyofadhiliwa hasa na Jumuiya ya Watafiti wa Kijiografia (SEG) na Programu ya Wanasayansi wa Kijiografia Bila Mipaka (GWB), ilifanywa katika Kambi ya Wakimbizi ya Kakuma na maeneo ya karibu. Lengo la mpango huo ni kutoa malengo ya kuchimba visima vya maji, kuanzisha mbinu bora ya kijiografia ya kuchimba maji, mafunzo ya wakimbizi na wafanyakazi wa Kakuma WASH (Maji, Usafi wa mazingira na Usafi), na kuongeza maarifa ya hydrogeology ya eneo hilo. ERT (electrical resistivity tomography) ilitumika kutofautisha granular overburden kutoka kwa udongo, mwamba wa hali ya hewa kutoka kwa mwamba uliovunjika, maji safi kutoka kwa maji ya chumvi, na kuelezea makosa. Mvunjiko wa tetemeko la ardhi ulionyesha waziwazi sehemu ya juu ya mwamba. Uunganisho wa ERT na refraction seismic ni uboreshaji mkubwa juu ya kawaida kukimbia moja-dimensional (1D) wima umeme soundings (VES) ambayo kudhani geology kabisa gorofa uongo. Hata hivyo, ni vigumu kutambua kwa uhakika viwanja vya maji vilivyo na uzalishaji mkubwa, chumvi kidogo, na fluoridi kidogo. Matokeo ya programu hiyo yalionyesha kwamba jiolojia na hidrogeolojia ya Kakuma na Kalobeyei ni tata zaidi kuliko ilivyodhaniwa hapo awali. "Hata hivyo, mwezi Mei 2016, miezi miwili baada ya kukamilika kwa mpango wa geophysical, visima vitatu vya uzalishaji wa juu vinavyojaribu uzalishaji wa kudumu wa 29 m 3 h, 40 m 3 h na 45 m 3 h vilichimbwa na kukamilika katika kile tunachokiita ""Northern Well Field.""" UNHCR inaonyesha kuwa kwa kutumia bomba la maji kwa muda wa saa 10 kwa siku, na kwa lengo la kutoa lita 20 za maji kwa kila mtu, vijito hivyo vitatu vya kwanza vinaweza kuandaa maji kwa wakimbizi 57,000. Kemikali ya maji kuchambuliwa kutoka moja tu ya visima hivi drilled moja kwa moja juu ya sehemu ya geophysical inaonyesha chumvi ya chini na mkusanyiko wa chini fluoride. Kwa ujumla, mbinu za kuchunguza maji katika Afrika Mashariki zimebadilika kidogo tangu miaka ya 1960. Programu hii inaonyesha kwamba mbinu za kisasa zinaweza kusababisha viwango vya mafanikio ya kuchimba visima vya maji, ubora wa maji, na uelewa wa jumla wa jiolojia na hydrogeolojia ya eneo fulani. Kakuma ni kambi ya wakimbizi iliyoko katika jangwa la Turkana, Kenya, kwenye urefu wa mita 600 juu ya usawa wa bahari. Kambi hiyo inasimamiwa kwa pamoja na Ofisi ya Kamishna Mkuu wa Umoja wa Mataifa kwa Wakimbizi (UNHCR) na Serikali ya Kenya. Kambi hiyo ilifunguliwa mwaka 1992 ili kuwakaribisha wavulana waliopotea wa Sudan ambao walikuwa wakimbizi wa vita vya pili vya wenyewe kwa wenyewe vya Sudan, vilivyomalizika mwaka 2005. "Mfano wa ""The Lost Boys of Sudan"" ni filamu ya Dave Eggers ""The Good Lie"" na filamu ya Reese Witherspoon." Kambi hiyo, ambayo kwa sasa inatoa hifadhi kwa wakimbizi wapatao 163,000 kutoka nchi 16 za Afrika Mashariki, ilibuniwa kwa idadi ya wakimbizi 100,000. Baada ya kuanzishwa kwa jimbo la Sudan Kusini mwaka 2013, watu wa Sudan waliokamatwa walihamishwa. Mapigano ya Sudan Kusini yamesababisha zaidi ya wakimbizi 46,000 wa kabila la Nuer na Dinka kuingia Kakuma tangu Desemba 2013. Pia, Kambi inaendelea kuwakaribisha wakimbizi kutoka nchi nyingine ambao wanakimbia njaa, ukame, "vita vya ng'ombe", msukosuko wa kisiasa, na migogoro mingine katika Afrika Mashariki. Kambi hiyo imegawanywa katika sehemu nne za makazi (Picha ya 3), na Kakuma 1 ni eneo la awali ambapo Wavulana Waliopotea waliishi, na Kakuma 4 ni eneo la kuishi la wawasili wa hivi karibuni. Mnamo Januari 2016, UNHCR ilikuwa ikijitayarisha kupokea wakimbizi wengine 60,000 (UNHCR.org), zaidi ya mara mbili ya uwezo wa awali wa kubuni wa Kambi. Mji huo umejengwa kwa ajili ya wakimbizi wapya ambao wamehamia katika kambi ya Kalobeyei, iliyoko kilomita 20 magharibi mwa mji wa Kakuma. Kalobeyei itakuwa ya kipekee kati ya kambi zinazofanya kazi kwa sasa za UNHCR kwa kuwa wakazi watahimizwa kufanya kazi ya kilimo badala ya kutegemea tu vyakula vya UNHCR. Kwa kuongezea, mwingiliano mkubwa na jamii ya mwenyeji (yaani Miongoni mwao ni Turkana, ambao ni watu wa asili ya Turkana, ambao ni watu wa asili ya Turkana. Kaunti ya Turkana ni kaunti kubwa zaidi nchini Kenya, na eneo la karibu kilomita 71,598 na idadi ya watu 855,399, takwimu zote mbili zikiwa sawa na zile za Mkoa wa New Brunswick nchini Canada. Hali ya hewa na mandhari ya Kakuma ni nusu kavu, kimsingi jangwa (Figure 5). Kiwango cha wastani cha joto cha kila mwaka katika Kakuma ni 28 ° C, na joto mara chache sana kushuka chini ya 21 ° C. Kwa wastani, mvua ya kila mwaka ya Calgary ni 32 cm, na kwa wastani, ni sawa na mvua ya kila mwaka ya Calgary. Mvua nyingi katika Kakuma huanguka kama matukio machache ya mvua kali mnamo Aprili na Novemba (Sura ya 6). Geological na Hydrogeological Setting Kakuma iko katika mwelekeo wa kaskazini magharibi ya Kenya Rift. Mfereji wa Kenya ni tawi la mashariki la sehemu kubwa zaidi, Mfumo wa Mfereji wa Afrika Mashariki. Sehemu ya Kenya Rift ni bonde pana la Turkana depression na Ziwa Turkana iliyoko kwenye mhimili wa Kenya Rift. 1999) na Eneo lililo karibu na Kakuma huitwa Nyanda za Lotikipi. Sottas (2013) anaelezea Lowasa za Lotikipi kama msongamano wenye umbo la sahani unaopakana mashariki na magharibi na safu za volkano. "Saucer yenyewe imejaa volkano inayotokana na sediments ya mto kutoka Miocene ya Kati (5,5 Ma) hadi sasa, kufikia unene wa juu wa mita 300. ""Saucer"" ni msingi wa sediments ni ya kati hadi Miocene ya Mapema (5,5 Ma) rhyolites, kisha umri wa Oligocene (ma 23.7-36.6 Ma) basalts chini ya miamba ya sedimentary ya sub-volcanic ya Paleocene hadi Cretaceous (ma 57.8-144 Ma) na hatimaye msingi wa Precambrian." Bonde la Lotikipi lina kasoro nyingi katika muundo wa horst na graben. Kama Kakuma Kambi ya Wakimbizi ni juu ya ukingo wa kusini wa Lotikipi Basin, wengi rhyolite outcrops kutokea katika eneo la utafutaji. Takwimu zilizopatikana za kuchimba zinaonyesha kwamba sediment overburden katika Kakuma hufikia kiwango cha juu cha karibu 40 m kwa unene. Kwa ujumla, chini ya mzigo huo, kampeni mbalimbali za kuchimba visima zilipata miamba ya volkano, ingawa miamba ya matope na ya moto pia imepatikana. uwezekano interfingering ya mwamba volkano na sediment unconsolidated zinahitaji kwamba mtu kutumia neno <unk>bedrock<unk> kwa tahadhari. Kwa sasa, maji ya chini ya ardhi ndiyo chanzo pekee cha maji katika Kambi ya Wakimbizi ya Kakuma na eneo linalozunguka. Kwa mfano, katika eneo la Turkana, kuna visima vingi vya maji vilivyotengenezwa katika eneo la Lhasa. Kakuma sio ubaguzi, kwani visima 15 vinavyokadiriwa kuwa vinapumua sasa vyote viko ndani au karibu na Laga Tarach (Picha ya 7), ambayo hutiririka labda siku chache kila mwaka. Sottas (2013), pamoja na data inapatikana kuchimba, inaonyesha kwamba wote sediments juu na chini, weathered (au fractured) mwamba kutumika kama aquifers. Utaratibu wa kawaida wa uchunguzi (yaani Kuunganisha bomba la kuchimba maji na kufungua sediment juu ya aquifers nyingi (mbele ya mazoezi ya kupendelea ya kuchunguza aquifer moja) na kuunganisha vipindi vya kuchunguza na vifaa vya kujaza tena, hufanya iwe vigumu sana kuamua mchango wa jamaa wa aquifer ya msingi dhidi ya aquifer ya sediment ya juu. Kwa kuongezea, habari za kuchimba visima kutoka kwa mashimo yaliyokuwa yameachwa ni nadra kuhifadhiwa, na habari ambazo zimehifadhiwa mara nyingi huwa na utata au zinapingana. Sottas alikata kauli kwamba mashimo mengi ya kuchimba maji hutoka katika miamba ya volkano na pia katika matope ya maji ya chini ya ardhi. Kwa ujumla, aquifer ya chini ya ardhi ina uwezo wa kuzalisha maji mengi na kuhifadhi maji mengi, na ina kiwango cha chini cha fluoridi, lakini ina uwezekano mkubwa wa kuambukizwa na bakteria. Kiwango cha chini cha maji ya mwamba wa volkano kinahusishwa na mavuno ya chini, viwango vya juu vya fluoride zinazotokea kiasili, na unyeti mdogo kwa uchafuzi wa bakteria. visima vingi vya maji katika eneo hilo ni vyenye chumvi. Kuongezeka kwa chumvi katika visima vya maji kumegunduliwa wakati wa vipindi virefu vya ukame (UNHCR, mawasiliano ya kibinafsi). Kwa kuwa hakuna habari ya geophysical ya shimo la kuchimba, na mazoezi ya kawaida katika Afrika Mashariki ni kuchunguza maeneo yoyote na yote ya uzalishaji wa maji, maelezo ya uhakika zaidi na ya kina ya ubora wa maji ya mifumo ya aquifer ya mtu binafsi ni changamoto. Vizuizi kuu vya kijiokemia juu ya maji ya kunywa ni salinities iliyoinuliwa na mkusanyiko wa fluoride ulioinuliwa. Mzunguko wa fluoride katika maji ya chini ya ardhi ni ya kawaida katika mazingira ya bonde la rift (Muhimu ya Jiolojia ya Matibabu, 2005). Sottas alikata kauli kwamba uwezekano mkubwa wa kuwa na viwango vya juu vya fluoridi unahusiana na mfumo wa matumbawe ya volkano yaliyopigwa na hali ya hewa. Katika visima 15 vya pampu vya Kakuma vilivyochunguzwa mnamo Julai 2016, viwango vya fluoridi vilikuwa kati ya 1.5 mg kwa lita na 8.4 mg kwa lita. Milnes (UNHCR, mawasiliano ya kibinafsi) ameona kwamba viwango vya fluoride mara nyingi huongezeka kwa kuongezeka kwa chumvi. Milnes amedokeza kwamba ambapo wote alluvial na volkano aquifers ni screened (yaani, kuzalisha maji), kushuka viwango vya maji katika alluvial aquifer, na kuongeza mchango kutoka aquifer volkano itasababisha kuongezeka fluoride na chumvi mkusanyiko. Maji ya maji ya chini ya ardhi katika kambi ya wakimbizi ya Kakuma yametolewa kwa njia ya maji ya chini ya ardhi kutoka Wadi Taraq, eneo ambalo limekuwa likikumbwa na mafuriko kwa miaka mingi. Mto Laguna una maji mengi ya maji, na maji ya chini ya ardhi hujazwa tena kutokana na mafuriko hayo. Maji ya mvua hutenda kama chanzo cha pili lakini cha moja kwa moja cha kuchaji. "Hakuna habari za kutosha kuhusu eneo la Kalobeyei, ambalo liko kilomita 30 magharibi mwa Kakuma.""" Ripoti ya Hydrogeological and Geophysical Investigations, Kalobeyei (2015) inaelezea jiolojia na hydrogeology ya eneo la Kalobeyei kama kuwa sawa sana na Kakuma, na alluvium ya udongo juu ya lava ya Tertiary, na lensi za mchanga zipo karibu na lagas kuu. Gicheruh alidhani kwamba rhyolites zilizopigwa na hali ya hewa ziliweka msingi wa maeneo mengi ya alluvium. Chini ya Tertiary, lava rhyolitic, ni interbedded basalts na miamba sedimentary, na Precambrian msingi. "Kutumia ""resistivity"" na ""water witching"" kwa njia ya 1-D kumekuwa kwa wingi katika Kaunti ya Turkana (Oxfam, 2009), ikiwa ni pamoja na katika Kambi ya Wakimbizi ya Kakuma na Kalobeyei (Gicheru, 2015) kama sehemu ya mipango ya mapema na ya sasa ya utafutaji wa maji." Hali ya jiolojia ya Rift Valley, pamoja na matokeo yaliyowasilishwa hapa, yanaonyesha jiolojia na hydrogeolojia ni ngumu sana na kubadilika ili kushughulikiwa na mbinu za 1D za geoelectric. Majaribio ya zamani ya watafiti wengine kutumia ERT (Sottas, 2013) huko Kakuma yalithibitisha kuwa matokeo hayangeweza kutafsiriwa. Katika kukagua sehemu zilizokusanywa hapo awali za upinzani, tulikubali kwamba kukusanya data ya refraction ya seismic ya mwenzake ingetoa uwezekano wa kutoa ufafanuzi wa wazi wa juu ya mwamba. Tafsiri ya uchunguzi wa awali wa upinzani yaweza kuwa na tofauti ya tofauti ya mali ya umeme kati ya lithologies overburdened na mwamba wa volkano ya chini inayoonyesha digrii mbalimbali za hali ya hewa. Kwa kuongezea, kwa kuzingatia kile tunachojua sasa, uchunguzi wa awali ulishindwa kuchunguza kina cha kutosha na juu ya urefu wa mstari wa kutosha kutambua mabadiliko ndani ya mwamba wa msingi na mzigo wa juu, ambayo ni kuona msemo wa msitu kupitia miti. licha ya mapungufu ya uchunguzi wa zamani wa 1D na 2D wa geoelectric, programu hii ilinufaika sana na matokeo yaliyokusanywa katika ripoti na masomo yanayopatikana. Wote zamani na hizi sasa uso uchunguzi geophysical walikuwa handicapped na kukosekana kamili ya data geophysical shimo. "Kulingana na utafiti wa utafiti wa ""geophysical data"" katika mashimo ya uchimbaji, kuna uwezekano mkubwa kwamba kuna uwezekano wa kugundua maji ya maji ya maji ya maji ya maji ya maji ya maji ya maji ya maji ya maji ya maji ya maji ya maji ya maji ya maji ya maji ya maji ya maji ya maji ya maji ya maji ya maji ya maji ya maji ya maji ya maji ya maji ya maji ya maji ya maji ya maji ya maji ya maji ya maji ya maji ya maji ya maji ya maji ya maji ya maji ya maji ya maji ya maji ya maji ya maji ya maji ya maji ya maji ya maji ya maji ya maji ya maji ya maji ya maji ya maji ya maji ya maji ya maji ya maji." Tofauti na sehemu nyingi za Afrika Mashariki, visima vya maji vilivyopo huko Kakuma vilijengwa kwa chuma, na hivyo kuondoa uwezekano wa kuchimba maji kwa njia ya kuchimba maji. ERT ni mbinu ya ramani ya usambazaji wa chini ya ardhi umeme upinzani katika sehemu ya msalaba (Figure 8). Malengo makuu ya uchunguzi wa ERT yalikuwa kutambua mchanga na mchanga wenye upinzani, wenye maji baridi. Data ya upinzani hukusanywa kupitia safu ya mstari wa electrodes iliyounganishwa na transmitter ya sasa ya moja kwa moja (DC) na mpokeaji wa upinzani, na sanduku la kubadili la elektroniki. Umbali kati ya electrodes kwa kiasi kikubwa udhibiti azimio usawa na wima wa data (mzunguko mdogo matokeo katika azimio la juu usawa na wima). Vivyo hivyo, urefu wa safu inadhibiti kina cha uchunguzi (safu ndefu hutoa kina kikubwa cha uchunguzi). Kukusanya data ni kufanyika katika mfululizo na automatiska fashion kwamba inachukua faida ya mchanganyiko wote wa uwezekano wa sasa sindano na uwezekano wa kipimo electrodes. "Kutumia ""2D Geotechnical Section"" na ""2D Finite Difference"" na ""2D Finite Element Inversion"" ni njia ya kuunda muundo wa mimea ya dunia." Katika programu hii, umbali wa electrode ulitofautiana kutoka mita 5 hadi 10, na kina cha uchunguzi kinachotofautiana kutoka mita 70 chini ya uso wa ardhi hadi mbps 140. Urefu wa mstari ulitofautiana kutoka 400 m hadi 1600 m. Sehemu 16 za ERT zilikusanywa kwa jumla ya kilomita 11.4 za mstari. Schlumberger gradient array ni moja ya njia za kuunganisha na kuunganisha voltage, na ina uwezo wa kupanua azimio la mviringo na wima, na inaweza kutumia upendeleo wa multichannel ABM LS. Lengo kuu la uchunguzi wa refraction ya tetemeko la ardhi ilikuwa kwa uhakika delineate juu ya mwamba, kama hata weathered mwamba volkano itakuwa kawaida kuwa kwa kiasi kikubwa kwa kasi compressional wimbi (P-wimbi) kasi kuliko overburden vifaa. Utafiti wa refraction ya seismic hasa ilitumia kushuka kwa uzito wa elastic na beam ya 40 kg (PEG-40) kama chanzo cha wimbi la compressional (Figure 9), ingawa nyundo ya 16 pauni ilitumiwa katika maeneo bila upatikanaji wa gari. Mstari wote ulipigwa risasi na geophones ya 40 Hz, na geophones moja katika kila kundi, na na geophones ya mita tano. Geometrics Geode 24 channel networked seismographs zilitumiwa kwa ajili ya uchunguzi wote. Mstari wa 144 ulipigwa risasi na seismographs sita za mtandao, ingawa baadhi ya mistari ilitumia njia chache kwa sababu ya vikwazo vya nafasi. Mstari wa refraction ya tetemeko la ardhi kumi zilikusanywa kwa jumla ya urefu wa mstari wa kilomita 5.8. Sehemu za sehemu za sehemu za sehemu za sehemu za sehemu za sehemu za sehemu za sehemu za sehemu za sehemu za sehemu za sehemu za sehemu za sehemu za sehemu za sehemu za sehemu za sehemu za sehemu za sehemu za sehemu za sehemu za sehemu za sehemu za sehemu za sehemu za sehemu za sehemu za sehemu za sehemu za sehemu. Programu ya uwanja wa kijiografia ilifanywa katika kipindi cha Januari 10 hadi Januari 22, 2016. Kazi ya shamba ilifanywa na ERT na seismic refraction crews kufanya kazi kwa wakati mmoja, kwa kawaida katika maeneo tofauti kutenganishwa na kilomita kadhaa. Trimble Geo7X Handheld GPS Kwa ajili ya makusudi ya shirika ya majadiliano, maeneo ya uchunguzi yamegawanywa katika maeneo matano ya jina la hiari (Picha 10 na 11): - Laga Tarach Kusini; - Mashamba ya Shamba la Kaskazini; - Mashamba ya Shamba la Kati; - Magharibi ya Kakuma 1; na - Laga Tarach Kusini ni eneo lenye udhibiti wa mashimo, lina visima vya mavuno na ubora wa maji, na iko katika, au karibu na, mfereji kuu wa Laga Tarach. Tarach Laga Kusini ni kusini na mashariki ya sehemu ya muda mrefu zaidi ya makazi (tangu 1992) ya Kakuma 1. Lengo la uchunguzi hapa ni pamoja na majaribio ya jumla ya mbinu ya uchunguzi, na kugundua maeneo ya kuchimba visima na uwezekano wa mavuno bora na viwango vya chini vya fluoride, ikilinganishwa na visima vilivyopo. "Kifaa cha ""Northern Well Field"" ni eneo la visima vyenye matokeo ya juu zaidi, kina udhibiti wa mashimo, na pia ni karibu na Laga Tarach, ambayo inawezekana inafanya kazi kama chanzo kikuu cha maji ya chini ya ardhi." Shamba la Bonde la Kaskazini linavutia hasa kwa sababu eneo lake linafanya iwe chanzo cha maji kwa Kalobeye na Kakuma, na pia kwa vijiji vya Turkana na majengo ya familia katika mazingira ya karibu. Malengo ya uchunguzi hapa ni pamoja na kupata maeneo ya kuchimba visima na uwezekano wa mavuno bora na viwango vya chini vya fluoride ikilinganishwa na visima vilivyopo. Sehemu ya Shimo la Kati iko karibu katikati ya Laga Tarach Kusini na Shamba la Shimo la Kaskazini, na pia iko karibu na Laga Tarach. Kuna visima kadhaa katika eneo hili; hata hivyo, udhibiti wa visima ni duni kwani visima vingi vimechimbwa kwa mkono au vina maelezo machache sana ya kijiolojia na hydrogeolojia. Shamba la Chungu la Kati liko kwenye ukingo wa kaskazini wa Kakuma 1 yenye watu wengi. Malengo ya uchunguzi hapa yalitia ndani kupata maeneo ya kuchimba visima yenye matokeo bora zaidi. Eneo la Magharibi la Kakuma 1 halina visima vya maji. Hata hivyo, visima vingi vilivyokatwa vimechimbwa katika eneo hili, ikiwa ni pamoja na <unk>Kakuma 1 VES 1 Borehole<unk> ambayo ilijaribiwa kwa 110 m3 h, ingawa na chumvi ya juu na mkusanyiko wa juu sana wa fluoride. Udhibiti mdogo wa kijiolojia upo katika eneo hili kwa sababu ya kukosekana kwa habari zilizopatikana zilizopatikana. Uzalishaji mkubwa uliojaribiwa kutoka kwa shimo la kuchimba visima unafanya eneo hili liwe lenye kupendeza kwa ajili ya uchunguzi. Kwa kuwa hakuna visima vinavyotoa maji katika eneo hili, kisima cha maji katika eneo la Magharibi mwa Kakuma 1 kitaleta chanzo cha maji karibu sana na makazi ya Kakuma 3 na 4 na uwezekano wa kuepuka usumbufu wa usambazaji wa maji wakati wa mafuriko katika lagas. (Mifereji ya mabomba iliyofunikwa mara nyingi huharibiwa na maji ya mafuriko.) Eneo la Kalobeyei lina kisima kimoja tu cha maji ambacho kimepimwa kuwa na kiwango cha maji ya m3 5 kwa saa. "Kama ilivyoelezwa hapo juu, eneo la Kalobeyei linaonekana kuwa tofauti sana na eneo la Kakuma, kwani Kalobeyei ina mwamba mkubwa, na lagas zilizo karibu ni ndogo sana kuliko Lagata.""" Uchunguzi katika eneo la Kalobeyei ulifanyika karibu na shimo la Kalobeyei lililopo, na katika lagas tatu ndogo karibu na Kambi mpya ya Wakimbizi ya Kalobeyei iliyopendekezwa, lagas Elelia, Esikiriait, na Kangura. Utafiti wa Mashamba ya Mashamba ya Mashamba Ingawa ni mdogo, data zote za shimo la shimo zilitumiwa kwa madhumuni ya uhusiano. Habari za kemia ya maji ni za thamani isiyo na uhakika, kwani visima vingi vya maji vilivyopo vimechunguzwa katika maeneo mengi, ikienea katika aquifers za juu na za chini. Hakuna kumbukumbu za kijiografia za mashimo ya kuchimba visima. Tafsiri ya mali za kimwili zilifanywa kupitia mchanganyiko wa vifungo vizuri kwa sehemu ya upinzani na P-wimbi kasi, na baadhi ya dhana ya tafsiri ya vipimo mali ya kimwili. "Kutokana na matokeo ya ""P-wave"" ya refraction, kwa kawaida inahusiana na mwendo wa 2000 m s, na kuelezea mwamba mkubwa zaidi na uwezo wa chini wa maji ya chini ya ardhi, ni msingi wa upinzani wa juu zaidi wa mwamba (zaidi ya 60 ohm) na ""mwamba wa juu"" na ""mwamba wa juu"" na ""mwamba wa juu"" na ""mwamba wa juu"" na ""mwamba wa juu"" na ""mwamba wa juu"" na ""mwamba"" na ""mwamba"" na ""mwamba"" na ""mwamba"" na ""mwamba"" na ""mwamba"" na ""mwamba"" na ""mwamba"" na ""mwamba"" na ""mwamba"" na ""mwamba"" na ""mwamba"" na ""mwamba"" na ""mwamba"" na ""mwamba"" na ""mwamba"" na ""mwamba"" na ""mwamba"" na ""mwamba"" na ""mwamba"" na ""mwamba." Kwa hivyo, jedwali la malengo ya kuchimba visima katika kila moja ya maeneo matano ya uchunguzi lilitolewa kwa UNHCR kama sehemu ya kuripoti mradi. Meza hii ilijumuisha eneo la uchunguzi, uchunguzi wa kijiografia uliotajwa, kuratibu za kijiografia (kwa UTM na latitudo-urefu), na asili ya kutafsiriwa ya aquifers zilizolengwa. Jamii hiyo ya mwisho ilitia ndani miamba mikubwa, yenye umajimaji, yenye chembechembe; miamba ya volkano iliyoporomoka; miamba ya maporomoko; na miamba iliyovunjika karibu na maporomoko. Pia, maeneo yenye chumvi nyingi, udongo mzito, mzigo usio na unyevu, mwamba mkubwa, mwamba mdogo sana, na volkano zilizoathiriwa sana zilitajwa kuwa zinapaswa kuepukwa. Katika Laga Tarach Kusini, aquifers uwezekano ni pamoja na maeneo ya overburden nene na mwamba weathered. Inastahili kutajwa kwamba shimo la awali la UNHCR lililochimbwa katika eneo hili ndilo shimo pekee la Kakuma lililochimbwa kabisa katika mwamba. Kiwango cha fluoride katika shimo la UNHCR ni 8 mg kwa lita, zaidi ya mara tano ya miongozo ya WHO na Kenya ya maji ya kunywa, na zaidi ya 4 mg kwa lita ambayo huaminiwa kutokea kwa fluorosis ya mifupa (Mafunzo ya Jiolojia ya Matibabu, 2005). Katika eneo la shimo la kaskazini, sehemu za upinzani na mwendo wa wimbi la P, zilizoungwa mkono na vifungo vya maji zilizopo, zilionyesha wazi mchanga na mchanga wenye unyevu, uliokuwa na mviringo mkubwa (Sura ya 12). Maeneo makubwa ya miamba ya chini ya ardhi yaliyotoweka pia yalifafanuliwa. Hata hivyo, aquifer granular kubwa, pamoja na ukaribu wa shamba la Well Kaskazini na Laga Tarach, chanzo cha recharge ya sekondari, iliongeza eneo hili kama kuwa na matarajio makubwa kwa ajili ya utafutaji zaidi na maendeleo. Hydrostratigraphy ya Central Well Field ni vigumu kuamua kwa uhakika kama visima vyote vya maji vilivyopo ni ama vimeandikwa vibaya, au vimechapishwa katika maeneo mengi, kuenea juu ya mzigo na mwamba. Kuna maeneo ya nyenzo nzito, saturated granular (Figure 13), pamoja na maeneo makubwa ya uwezekano wa volkano weathered. Uwezekano wa kuongeza mazao ya maji ya chini ya ardhi ya visima vingi vilivyochimbwa kwa mkono katika eneo hili ni uwezekano mdogo sana kutokana na geophysically kutafsiriwa chini, aquitard ya chini. Eneo la uchunguzi Magharibi mwa Kakuma 1 lina matarajio makubwa ya mavuno ya juu ya maji ya chini ya ardhi. Kwa sababu ya mwendo wa P wa mbps wa 90 unaonyesha kwamba mwamba unaofaa uko chini zaidi hapa kuliko mahali pengine popote katika Kakuma au Kalobeyei. Ingawa hakuna visima vilivyokamilika katika eneo hili, rekodi za kuchimba visima vya visima vilivyopuuzwa zinaonyesha matokeo ya majaribio ya 110 m3 h, sediments hadi 66 mbg, na mawasiliano ya miamba ya sedimentary juu ya volkano kwa 84 mbg. Chimbuko hilo liliachwa kwa sababu ya chumvi ya juu (4377 mg/l) na viwango vya juu sana vya fluoride vya 10.2 mg/l. Hata hivyo, rekodi za kuchimba zinaonyesha kwamba chumvi nyingi zilipatikana katika kina cha mbgs 78. Uchimbaji uliofuatwa kwa uangalifu, kuandamana na uchimbaji wa geophysical ya shimo, na ujenzi wa kisima, haswa kuchunguza aquifers ya chumvi ya chini, inaweza kusababisha kisima cha juu katika eneo hili muhimu la kimkakati. Katika eneo la uchunguzi wa Kalobeyei, katika lagas El-Alayya na Es-Sikriyat, uchunguzi wa ERT na upungufu wa seismic, pamoja na uchunguzi wa kuona wa outcrop, unaonyesha wazi overburden ya chumvi au clayey juu ya mwamba wa chini (Figure 14). Magharibi mwa Lagha Kangura, karibu na kisima pekee kilichopo katika eneo hilo (Kalobeyei, kipimo cha m3 ya saa ya 5 kutoka Gicheru, 2015) sehemu nne za ERT zilionyesha angalau mbili, na labda tatu, kuanguka kwa kasi, lakini makosa ya umeme (Figure 15). Takwimu za kupasuka kwa matetemeko ya ardhi zinaonyesha kwamba mwamba ni wa chini sana. Mipango ya kuchimba imependekezwa karibu na mapungufu ambapo mwamba unatarajiwa kupasuka (Sura ya 16), na kwenye upande wa mapungufu karibu na lagas ambapo uwezekano wa mapungufu ya mwamba wa maji inaweza kufaidika na malipo ya pili wakati wa matukio ya mafuriko. Kwa kuzingatia mchanga wa kijivu uliojaa, uliopangwa kwa geophysically katika uwanja wa shimo la kaskazini, matokeo na tafsiri za programu hii ya geophysical ya 2016 zilitumiwa kuweka shimo la 13 (mita 525 kando ya ERT7) mnamo Mei 2016 (UNHCR, mawasiliano ya kibinafsi; tazama Picha ya 12). Chimbuko la 13 lilijaribiwa kwa mavuno ya kudumu ya 40 m 3 h, conductivity ya kioevu ya 592 m 3 l (karibu 380 mg l) na mkusanyiko wa fluoride wa 0.9 mg l (chini ya miongozo ya maji ya kunywa ya WHO na Kenya ya 1.5 mg l). "Kemia ya maji kutoka kwa Borehole 13 inasaidia sana nadharia kwamba viwango vya juu vya fluoride vinahusishwa sana na aquifer ya volkano ya hali ya hewa. """ UNHCR ilichimba visima viwili vya ziada katika upanuzi wa kaskazini wa uwanja wa kisima cha kaskazini. Kwa mfano, katika mashimo mawili ya maji, matokeo ya majaribio ya kuhifadhi maji yalikuwa 29 m3 kwa saa na 45 m3 kwa saa (UNHCR 2017). Mpaka Machi 2017, bomba la kilomita 13 litakamilika kati ya mashimo haya na makazi ya wakimbizi ya Kalobeyei, ambayo itaweza kutoa karibu lita 1,200,000 za maji kwa siku kwa wakimbizi na Turkana wa ndani wanaoishi huko. Kwa sasa, wakimbizi 22,000 wamehamia katika makazi ya wakimbizi ya Kalobeyei, na kuna mipango ya kupanua idadi hiyo hadi watu 60,000, ambao wote watategemea maji kutoka kwa mashimo haya (Kifurushi cha Operesheni cha UNHCR 2017). Programu hii ya kijiografia imeweka alama nyingine nzito, alluvial, uwezekano wa fluoride ya chini na uzalishaji wa juu wa aquifers, na Magharibi ya Kakuma 1 kuwa maarufu zaidi. "Kulingana na ripoti ya UNHCR ya mwaka 2016, ""majaribio ya uzalishaji endelevu yalifanywa kwenye visima 20 vya uzalishaji huko Kakuma na Kalobeyei, na uzalishaji wa wastani wa visima 20 hivyo ulikuwa 22m3 kwa saa.""" Kwa mfano, kuna visima viwili ambavyo vimepimwa kwa kiwango cha juu cha 40 m3 kwa saa. Pia ni muhimu kutambua kwamba visima vingi kavu, brake, uzalishaji wa chini, au fluoride mkusanyiko wa juu sana walikuwa drilled katika mchakato wa kukamilisha visima zilizopo mafanikio. Mbali na kuboresha kiwango cha mafanikio ya kuchimba, mchanganyiko wa tomografia ya upinzani wa umeme na refraction ya seismic imetoa uelewa bora wa jumla wa hydrostratigraphy katika Kakuma na katika eneo la Kalobeyei. Katika Kakuma, picha ya 2D ni muhimu kwa kutafsiri usambazaji wa nafasi ya mabadiliko ya haraka ya chumvi, misaada ya mwamba, mawasiliano ya volkano na sediment, na kiwango sahihi cha upande wa laga muhimu ya alluvial. Wadi) amana. Katika eneo la Kalobeyei, uchunguzi wa tetemeko la ardhi umeonyesha kuwa eneo hilo ambalo limekusudiwa kuwa makao ya wakimbizi 60,000 na jamii ya Turkana ya wakimbizi 23,000 huenda likawa na changamoto kubwa zaidi ya rasilimali za maji kuliko ilivyodhaniwa hapo awali kutokana na mwamba wa chini sana. Utafiti wa ERT huko Kalobeyei umegundua maeneo makubwa ya chumvi ya juu, pamoja na makosa kadhaa yaliyofafanuliwa vizuri ambayo yanaweza kuwa malengo ya kuchimba visima. Programu bora za kijiografia zitaongeza viwango vya mafanikio ya kuchimba visima. Pia, uchunguzi wa kijiolojia ulioboreshwa wakati wa kuchimba, uandishi wa geophysical wa visima vya PVC, ukaguzi na kutengwa kwa hydraulic ya aquifers za kuchagua, kuongeza habari kutoka visima vilivyopuuzwa, uhifadhi bora wa data, sampuli ya kuaminika ya hydrochemical, na kuanzisha visima vya ufuatiliaji wa kujitolea, zote zitasaidia sana katika tafsiri ya data ya geophysical ya uso. "Wanaume hao waliopotea kutoka Sudan walipofika Kenya miaka 25 iliyopita, utafiti wa maji katika maeneo kama hayo yenye uhaba wa maji kama vile Kakuma, ungefaidika kwa kufanywa kwa utaratibu badala ya kwa njia ya ""kijuu-juu"" ambayo kwa kawaida huonyesha hatua za mwanzo za usambazaji wa maji katika hali ya mgogoro." Ingawa programu za utafutaji za hali ya juu pia zitakuwa na gharama kubwa kuliko upimaji wa umeme wa wima wa 1-D na uchawi wa maji, matokeo ya viwango vya mafanikio ya kuchimba visima vinaweza kutoa faida za bajeti za fidia. Programu hiyo ilifadhiliwa na Shirika la Wataalamu wa Jiolojia ya Utafiti (SEG) na Shirika la Wanafunzi wa Sayansi ya Jiolojia Bila Mipaka (GWB). UNHCR ilitoa upatikanaji wa kambi, upatikanaji wa hifadhidata yao ya maji ya chini ya ardhi, na mwelekeo kuelekea masuala ya wasiwasi. "Msaada wa kiutawala na vifaa kwa ajili ya utafiti huu ulitolewa na NGO ndogo IsraAid, ambayo taarifa ya utume ni ""kusaidia watu duniani kote kushinda mgogoro mkali"" ""Dr. Ellen Milnes, kutoka UNHCR na Chuo Kikuu cha Neuchatel, alitoa msaada sana maudhui ya mapitio ya karatasi hii." Vifaa vyote vya geophysical na matengenezo ya vifaa vilitolewa kwa programu hii, bila gharama kwa programu, na Paul Bauman Geophysics Ltd. Wanafizikia wa Kanada hapa chini hawakupokea malipo yoyote kwa huduma zao, na walishiriki katika sehemu hii ya uwanja wa mradi huu wakati wa wakati wao wa " likizo ". Programu ya shamba ilifanywa na wataalamu sita wa jiolojia kutoka Advisian WorleyParsons. Wafanyakazi wa ushauri wa WorleyParsons ni pamoja na Paul Bauman, Erin Ernst, Doug MacLean, Colin Miazga, Randy Shinduke, na Landon Woods. Franklin Koch, ambaye pia alikuwa mwanafunzi intern katika Advisian WorleyParsons, alishiriki kutoka Chuo Kikuu cha Calgary. Dk. Alastair McClymont, kutoka Advisian WorleyParsons, alisaidia katika kupanga na usindikaji wa data. Mkutano huo ulifanyika na wanafunzi 28 wa shule ya msingi ya Israel, ambao ni wanafunzi wa shule ya msingi ya Israel. Wafanyakazi wa UNHCR na wafanyakazi wa Turkana walipokea malipo ya kazi kwa kiwango cha juu cha malipo ya kazi ya UNHCR. Paul Bauman ni Mkurugenzi wa Ufundi wa Kikundi cha Geophysics katika Advisian WorleyParsons. Ana uzoefu wa miaka 30 katika upimaji wa karibu wa uso wa ardhi kwa maji ya chini ya ardhi, rasilimali za asili, handaki, mabomu yasiyolipuka, taka za viwanda, makaburi ya kale, na kimsingi chochote ambacho mtu anaweza kutafuta bila kuchimba au kuchimba. Paul amekuwa akitumia suluhisho za kijiografia kwa changamoto za maji ya chini ya ardhi katika maeneo ya mbali zaidi ya kazi yake, ikiwa ni pamoja na Afrika, Amerika ya Kati, Asia ya Kusini, na nyumbani kwake nchini Canada. Erin Ernst alimaliza shahada ya B.Sc. katika Geophysics na M.Sc. Chuo Kikuu cha Calgary katika Hydrogeophysics Alipokuwa akifanya kazi katika Advisian, alisafiri kote Canada, akipata uzoefu wa jangwa lisilogunduliwa, ushirikiano na Mataifa ya Kwanza ya Canada, helikopta, mchanga wa mafuta, na maeneo mengine mengi ya kipekee na hali. Landon Woods amekuwa akifanya kazi na timu ya jiophysics ya Advisian (WorleyParsons Group) kwa miaka saba iliyopita. Kazi yake ya shambani imemchukua ulimwenguni pote, kutia ndani Madagaska, New Zealand, Israeli, na Kenya. Landon alimaliza B.Sc. Katika Chuo Kikuu cha Calgary, anafanya utafiti wa kijiolojia na geofizikia ya karibu na uso wa dunia. "Hiyo ni kwa sababu ya utafiti wa utafiti wa ""Hydrology"" na ""Essentials of Medical Geology: Impacts of the Natural Environment on Public Health"" (U.S.A. 2005)." Mhariri Mkuu: Olle Selinus. Elsevier Academic Press, Burlington, MA. P.S. - P.S. - P.S. - P.S. - P.S. - P.S. - P.S. - P.S. - P.S. - P.S. - P.S. - P.S. - P.S. - P.S. - P.S. - P.S. - P.S. - P.S. Habari za Global, Canada, Agosti 1, 2016 Calgary tayari imezidi jumla ya mvua ya kila mwaka. "Kama ilivyoelezwa katika taarifa ya ""Kalobei New Refugee Camp Water Project,"" ""Kalobei New Refugee Camp Water Project,"" ""Kalobei New Refugee Camp Water Project,"" ""Kalobei New Refugee Camp Water Project,"" ""Kalobei New Refugee Camp Water Project,"" ""Kalobei New Refugee Camp Water Project,"" ""Kalobei New Refugee Camp Water Project,"" ""Kalobei New Refugee Camp Water Project,"" ""Kalobei New Refugee New Refugee Camp Water Project,"" C. M. Gicheruh, Earth Water Ltd. Imeandaliwa kwa ajili ya Kamishna Mkuu wa Umoja wa Mataifa kwa ajili ya Wakimbizi (UNHCR). Oktoba, 2015. 73 p. Kellett, Richard na Bauman, 2004 Kupata ramani ya maji ya chini ya ardhi katika regolith na mwamba uliovunjika kwa kutumia geophysics ya ardhi: Utafiti wa kesi kutoka Malawi. Kurekodi. Kitabu cha Vol. Nambari ya 29. 2. Uwezekano wa kupata L. H. na Barker, R. D., 1996. Utafiti wa 3D wa upinzani na inversion ya data Geophyiscal Prospecting, Buku. 443 - Toleo la tatu, 499-523 "Kenya, K. K. Morley, W. A. Wescott, J. A. Stone, J. M. Harper, R. M. Wigger, S. T. Day, R. A. 1999, ""Geology and Geophysics of the Western Turkana Basins,"" Kenya, C. K. Morley, Ed., ""Geoscience of Rift Systems: Evolution of East Africa: AAPG Studies in Geology,"" No." (Sura ya 44) [Kutoka kwa ukurasa wa 44] Oxfam, Septemba 2009 Ripoti ya Utafiti wa Hydrogeological: Uchunguzi wa Rasilimali za Maji ya Chini ya Ardhi katika Turkana Kusini (Rifti Valley Catchment Area). Imeandaliwa kwa ajili ya Mradi wa Maji wa Lopur huko Lopur. Ref. La, sivyo. WDG-997C-998C-998C-998C-998C-998C-998C-998C-998C-998C-998C-998C-998C-998C-998C-998C-998C-998C-998C-998C-998C-998C-998C-998C-998C-998C-998C-998C-998C-998C-998C-998C-998C-998C-998C-998C-998C-998C-998C-998C-998C-998C-998C-998 (Hisabati ya Ufa ya Ufa ya Ufa ya Ufa ya Ufa wa Ufa wa Ufa wa Ufa wa Ufa wa Ufa wa Ufa wa Ufa wa Ufa wa Ufa wa Ufa wa Ufa wa Ufa wa Ufa wa Ufa wa Ufa wa Ufa wa Ufa wa Ufa wa Ufa wa U Sottas, Jonathan, 2013 Utafiti wa Kijiolojia wa Mfumo wa Aquifer wa Kakuma, Kenya. Master Thesis ya kuhitimu Chuo Kikuu cha Neuchatel. Juni, 2013 106 - Ukurasa wa UNHCR, 2016. Kenya: Wakimbizi wa Kenya wakimbiziwa na UNHCR, wakimbizi wa Kenya wakimbiziwa na UNHCR, wakimbizi wa Kenya wakimbiziwa na UNHCR, wakimbiziwa na UNHCR "Kenya: ""Kenya ni nchi ya kwanza duniani kuwa na mfumo wa ulinzi wa usalama wa hali ya hewa"" (Kenya: Kenya Operational Update, 16 Jan 2017 - 31 Jan 2017), na ""Uwanja wa Ndege wa Umoja wa Mataifa"" (UNHCR, 16 Jan 2017) ni kituo cha utafiti wa hali ya hewa cha Kenya." UNHCR Water Well Data, Februari 2015 Aprili 2006 Picha ya 3A: Wilaya ya Turkana, Usambazaji wa nafasi ya vyanzo vya maji