Environ. Eng. Res. 2013 June,18(2) : 95-101 Research Paper http://dx.doi.org/10.4491/eer.2013.18.2.095 pISSN 1226-1025 eISSN 2005-968X

Rainfall Harvesting as an Alternative Water Supply in Water Stressed Communities in Aguata- Area of Southeastern

Ephraim Okpoko1†, Boniface Egboka2, Luke Anike2, Elizabeth Okoro2 1Department of Geology, University, Uli 431004, Nigeria 2Department of Geological Sciences, Nnamdi Azikiwe University, Awka 420001, Nigeria

Abstract Alternative sources of water are sought in some water stressed communities in the study area. The study focuses on the Aguata-Awka area of southeastern Nigeria. Aquifers occur at great depths, and surface waters may be far from homesteads. The scarcity of water has necessitated the people to adopt various local technologies for harvesting rainfall. The local technology includes collecting rainwater from roofs and channeling the water into large underground tanks, shallow wells and surface reservoirs. Large concrete tanks of 6 m × 6 m × 4 m dimensions are often built underground and can store 144 m3 of water. Surface reservoirs built on 4 m concrete pillar supports having dimensions of 10 m × 10 m × 4 m and have a storage capacity of 400 m3. Water samples were collected at 3 different locations of , Ekwulobia, and Awka and were analyzed for their physical, chemical, and bacteriological parameters. Results indicate a range of values for pH, 5.9 to 7.1; turbidity, 0.9 to 2.7; total dissolved solids, 80 to 170 mg/L; total hardness, 4.5 to 6.4 mg/L; magnesium, 1.2 to 1.4 mg/L; bicarbonate, 19.4 to 83.6 mg/L; and sulfate, 3.6 to 6.4 mg/L. Bacteriological analysis results were negative for fecal and total coliform counts. All parameters, with the exception of pH where aluminum and galvanized iron roofs are used for collection, fall within the recommended guidelines for drinking water quality of the World Health Organization, and the Standard Organization of Nigeria, new Nigerian standards for drinking water quality. Magnesium is above the maximum permitted level for consumer acceptability of the Nigerian standards for drinking water quality. The water can be classified as fresh moderately hard and soft. The water can be described as a calcium and bicarbonate type.

Keywords: Harvesting rainwater, Local technology, Reservoirs, Roofs, Stressed communities

1. Introduction Rainwater harvesting systems may be installed and serviced in remote villages, and may be constructed with local materials and Water availability is dependent on climate, geologic, hydro- local human power for low cost and efficient maintenance [5]. logic, and hydrogeological factors. The adverse conditions pre- The study focuses on the Aguata-Awka area in southeastern vailing in the Aguata-Awka area, with a land size of about 525 Nigeria (Fig. 1). It is bounded by latitudes 5°56′ and 6°15′N and km2, has necessitated the development of local technology to longitudes 7°00′ and 7°12′E (Fig. 2). The simple local technol- cope with the water scarcity in the area. Favorable climatic con- ogy adopted by the people involves collection of water from ditions bring rain in the months of April to October, which is roof channels, and channeling it to surface or underground res- stored by the people for later use. ervoirs. This alternative source of water supply is meeting the Rainwater harvesting in the tropical regions of the world is water requirements of the semi-urban and rural communities practiced for domestic, commercial, and agricultural uses [1, whose population range from 5,000–30,000. 2]. Household rainfall catchment systems are very appropriate The Aguata-Awka area consists of hills, valleys, and plains. in areas with average rainfall greater than 200 mm per year and The maximum elevation is 335 m above sea level in the south no other accessible water source [3]. Rainwater is ubiquitous and slopes to 61 m to the northeast. The climate of the area is and free of charge, and is gaining interest as a good water sup- tropical and experiences two climate seasons: the rainy season ply option to solve water supply problems and increasing water and the dry season. The rainy months begin in April and last un- charges. It serves as one of the most appropriate alternatives to til October, while the dry season, which is characterized by little treated water [4]. Rainwater is one of the purest sources of water. or no rainfall prevails from November to March. The amount of

This is an Open Access article distributed under the terms of the Creative Received October 16, 2012 Accepted May 02, 2013 Commons Attribution Non-Commercial License (http://creativecommons. † org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, Corresponding Author distribution, and reproduction in any medium, provided the original work is E-mail: [email protected] properly cited. Tel: +234-8066667445

©Copyright Korean Society of Environmental Engineers 95 http://www.eer.or.kr Ephraim Okpoko, Boniface Egboka, Luke Anike, Elizabeth Okoro

Fig. 1. Map of Nigeria with study area in Anambra State indicated.

Fig. 2. Map of study area.

http://dx.doi.org/10.4491/eer.2013.18.2.095 96 Rainfall Harvesting as an Alternative Water Supply

rainfall for the years 1993 to 2010 ranged from 1,525.4 to 2,505.1 mm. Average annual precipitation for the period is 1,937.9 mm. Average maximum monthly temperature for the rainy season is 29.5°C while the minimum temperature is 23.6°C. In the dry season, the average maximum temperature is 34.5°C while the minimum temperature is 23.8°C. Average evaporation rate val- ues for the rainy and dry seasons are 2.2 and 4.4 mm, respectively (Table 1). The study area lies within the Anambra basin and is underlain by the Ameki formation, its lateral equivalent the Nanka sands (Eocene), the Imo shale (Paleocene) and its lateral equivalent the sandstone [6, 7]. The objective of this study was to investigate the use of alter- native local technology methods adopted by the people for over- Fig. 3. Materials sourced from the local market and used for fabrication. coming water problems in their localities.

2. Materials and Methods of evaporation. Water samples during rainfall were collected and analyzed for their physical, chemical, and bacteriological pa- The study is mainly field oriented. Visits were made to com- rameters. Collection of water samples were made using plastic munities to ascertain their mode of water supply in the dry sea- containers and kept under refrigeration prior to analysis. Analy- son. Mode of construction, and materials were sourced (Fig. 3) ses were carried out within 48 hr at the Water Quality Laboratory locally. Pictures were taken and used to capture the situation on of Anambra State, Rural Water Supply and Sanitation Agency— ground. Harvesting rainwater ameliorated the suffering of the the United Nations Children’s Fund assisted, Awka. people. The pH was measured using a pH meter (Jenway3051; Jen- Meteorological data for the years 1993 to 2010 were obtained way Ltd., London, UK). Temperature, total dissolved solids, and for rainfall, temperature, and evaporation from the records of conductivity were measured using a conductivity meter (bridge the Nigerian Meteorological Agency outstation, Awka [8]. In- type, MC; Kent-EIL5013; Kent Industrial Measurements Ltd., 2+ 2+ 2+ 2- stalled equipments at the agency are the standard ordinary rain Chertsey, UK). The cations and anions: Ca , Mg , Fe , SO4 , - - gauge, and self-recording rain gauge, for measuring amount of Cl , NO3 , PO4-P, and S1O2 were determined using a DREL spec- - 2- rainfall. Dry bulb and wet bulb thermometers, for measuring trophotometer (HACH, Loveland, CO, USA); HCO3 and CO3 by temperature, and the Piche Evaporimeter for measuring the rate the titration and calculation method, while total hardness was

Table 1. Amount of rainfall, average max and min temperature (November–March), average max and min temperature (April–October), and average evaporation rates (1993–2010 for Awka area) Dry (Nov-Mar) Wet (Apr-Oct) Year Rainfall (mm) Aver max–min temp Aver evaporation Aver max–min temp Aver evaporation (°C) (mm) (°C) (mm) 1993 1,627.0 33.9–23.3 6.8 31.0–23.6 4.2 1994 2,081.7 34.3–23.3 4.7 30.8–23.4 1.9 1995 2,477.9 34.1–23.0 4.2 31.3–23.1 1.9 1996 1,826.7 34.4–24.8 3.9 30.9–23.5 2.2 1997 1,907.0 34.1–24.1 4.7 31.9–23.4 2.1 1998 2,086.7 35.5–24.8 5.1 30.8–24.2 2.4 1999 2,505.1 33.6–24.3 4.0 30.9–23.6 2.4 2000 1,893.0 34.4–24.0 5.1 30.8–23.5 2.5 2001 1,555.9 34.5–25.1 4.3 31.9–23.6 2.4 2002 1,525.4 34.7–24.2 4.7 31.5–23.6 2.2 2003 1,881.1 34.6–25.1 4.3 31.5–23.9 2.1 2004 2,089.6 34.4–24.9 4.5 30.8–23.7 2.2 2005 1,897.8 34.1–24.1 4.1 31.3–24.1 2.2 2006 1,703.2 34.5–23.4 3.3 31.1–23.6 1.5 2007 2,026.8 35.0–22.4 4.0 31.5–23.5 1.9 2008 2,056.7 34.8–21.9 4.6 31.1–23.3 1.8 2009 2,154.6 34.7–23.4 3.1 31.6–23.4 1.8 2010 1,585.9 35.9–23.3 3.3 31.7–23.7 1.9

97 http://www.eer.or.kr Ephraim Okpoko, Boniface Egboka, Luke Anike, Elizabeth Okoro

obtained by the titration method. Fecal and total coliforms were determined using the Hatch Millipore bacteriological kit membrane (filtration method). All analytical methods and results obtained were within the opera- tional standards of the Standards Organization of Nigeria (SON) [9], the World Health Organization (WHO) [10], and GEMS/Wa- ter operational guide [11].

3. Results and Discussion

Water samples were collected from aluminum, galvanized Fig. 4. Bucket in funnel shape form for collecting water from roof. iron sheet and concrete roofs in Agulu, Awka, and Ekwulobia communities, respectively. Because of the dearth of water in the area, the situation has necessitated the indigenous people/lo- cal populations to resort to rainfall harvesting as an alternative from any of samples (Table 2). source of water supply. Results indicate the pH values to be 5.9 Bacteriological analysis results were negative for fecal and for the galvanized iron sheet, 6.2 for aluminum, and 7.1 for con- total coliforms counts. All parameters, with the exception of pH crete roof sources. Turbidity values obtained ranged from 0.9 to for the aluminum and galvanized iron roofs, conformed with the 2.7 mg/L, while total dissolved solids were determined to be 80 recommended guideline standards of the WHO [10, 12] and the to 170 mg/L, and conductivity values are between 160 and 360 SON Nigerian standards for drinking water quality (NSDWQ) [9]. µS/cm. The magnesium ion analyzed however is above the maximum Chemical analysis of calcium determined a range between permitted level for consumer acceptability of the NSDWQ, 2007. 3.4 and 5.2 mg/L, and magnesium was determined to vary from The water is slightly acidic to neutral and can be classified as 1.2 to 1.4 mg/L. The bicarbonate determined ranged from 19.4 fresh and soft. The rainwater can be described as the calcium to 83.6 mg/L while sulfate concentrations were determined to and bicarbonate type. The urban and rural populace has devel- range between 3.6 and 6.4 mg/L. A value of 0.1 mg/L for iron oped local technology which involves the use of U-shaped alu- was obtained for the galvanized iron roof. Total hardness ranged minum and galvanized iron materials. They are hung from the from 4.5 to 6.4 mg/L. No nitrate or phosphate ions were detected roof and fitted into a bucket like funnel for collecting rainwater

Table 2. Water quality analysis of rainfall in 3 communities compared to the Standard Organization of Nigeria - Nigerian standards for drinking water quality (NSDWQ) 2007 Agulu Awka Ekwulobia NSDWQ (aluminium) (galvanized iron sheet) (concrete) pH 006.2 005.90 007.10 6.5–8.5 Temperature (°C) 027.0 027.00 027.00 Ambient Appearance Clear Clear Clear - Color (Pt-Co) 001.7 002.60 004.20 015.0 Turbidity (NTU) 000.9 002.70 002.60 005.0 Conductivity (µS/cm) 220.0 340.00 160.00 1,000.0 Calcium (mg/L) 003.4 004.10 005.20 - Magnesium (mg/L) 001.2 001.40 001.30 000.2 Sulfate (mg/L) 003.6 004.30 006.40 100.0 Chloride (mg/L) 000.3 000.40 000.20 250.0 Bicarbonate (mg/L) 019.4 026.70 083.60 - Carbonate (mg/L) 009.1 009.40 020.10 - Nitrate (mg/L) 00 000 000.00 000.00 050.0 Phosphate (mg/L) 00 000 000.00 000.00 - Iron (mg/L) 00 000 000.10 000.00 000.3 Total hardness (mg/L) 004.5 005.20 006.40 150.0 TDS (mg/L) 11000 170.00 080.00 500.0 Silica (mg/L) 00 000 000.02 000.03 - Fecal coliform (CFU/100 mL) 00 000 000.00 000.00 000.0 Total coliform (CFU/100 mL) 00 000 000.00 000.00 010.0 NTU: nephelometric turbidity unit, TDS: total dissolved solids, CFU: colony forming unit.

http://dx.doi.org/10.4491/eer.2013.18.2.095 98 Rainfall Harvesting as an Alternative Water Supply

Fig. 5. Concrete reservoirs constructed above and below ground level. Fig. 8. Adequate structural design with pillar in reservoir to prevent collapse of wall.

a GL b

60 cm

Wire mesh

Fig. 6. Concrete reservoir of 6 m × 6 m × 4 m dimensions is built un- Fig. 9. (a) Cross sectional view and (b) top view of hand-dug well. derground and serves as source of water for poultry farming. GL: ground level.

Funnel for storing water as supplementary containers (Fig. 7). They are a b 6m commonly used during the rainy season, especially in rural ar- Metal cover 120 cm eas where pipe line network is lacking. These reservoirs are in 6 m WL Rainy season all the households in Nanka, Ekwulobia, Amesi, Akpo, and Umu- chu communities. Adequate structural designs are carried out to 113 cm prevent collapse or leakage into the sandy aquifers housing the Tap reservoirs (Fig. 8). GL WL Dry season G. L Deep hand-dug wells in the area serve dual purpose (Fig. 9). 4 m Water is stored in them from rainwater collected for domestic 48 cm Stair case purposes and at the same time rills erosion within compounds is checked. Wire mesh is placed at the mouth of entry into the reservoirs, plastic tanks and hand-dug wells, to hold back par- Fig. 7. (a) Schematic diagram of 4,500 L polyvinyl chloride (PVC) tank and (b) water levels in concrete reservoir in the rainy and dry ticulate materials, droppings from birds, leaf straws and leaves seasons. GL: ground level, WL: water level. falling on roofs during windy storms. The nets prevent dirt sedi- ments being washed from roofs, and mosquitoes from breeding in the water tanks [13]. Awka, Agulu, Nanka, Oko, Isuofia, Amesi, Ukpo, and Umu- (Fig. 4). Water collected is channeled into large concrete under- chu are underlain by the Nanka sands. The geological forma- ground tanks, shallow hand-dug wells and surface reserviors tion in the area consists of uncemented loose, medium to coarse (Fig. 5). Concrete reservoirs of 6 m × 6 m × 4 m dimension are grained and pebbly quartz sand. Here the infiltration capacity of either built on pillar supports or built underground for greater the soil is high and aquifers occur at great depths. storage capacity (Fig. 6). Occurrence of groundwater and surface water are dependent In the rainy season, the reservoirs are filled and water can be on geology and topography. Water levels are 100 to 300 m below conveniently collected from the taps constructed at the surface. ground surface in places [14], while the water table however be- The concrete reservoirs of 6 m × 6 m × 4 m dimension have a comes more shallow towards water courses. storage capacity of 144 m of water, and smaller polyvinyl chlo- The poor rural people cannot drill water boreholes for their ride (PVC) tanks of 4,500 and 9,000 L capacities are also used domestic and agricultural purposes as the costs for drilling bore-

99 http://www.eer.or.kr Ephraim Okpoko, Boniface Egboka, Luke Anike, Elizabeth Okoro

(HNO3) which is a major component of atmospheric acidifica- tion. The pH levels of 6.2 and 5.9 from aluminium and galvanized iron roofs, respectively, indicate the water samples to be acidic in nature. Additionally, particulate materials, which include dust from erosion and landslides in the area; soot, ash, and smoke from cottage industries and homes; and pollen, pores, algal cells from biota, are emitted into the atmosphere and carried in sus- pension during precipitation into surface reservoirs/systems and groundwater systems.

4. Conclusions

Fig. 10. Water from water tanker vendors are sold to the people at The inhabitants of the Aguata-Awka area in the southeast re- exorbitant prices. gion of Nigeria are faced with acute problems of water supply in the dry season of the year. The aquifers occur at great depths and are difficult to exploit by the rural poor because of cost implica- tions. The surface waters are far from homesteads and a lot of holes are very prohibitive. River, streams, and springs are far from energy, time and money is spent in search of water. many homesteads, requiring the people to trek long distances of The benefits of rainwater harvesting are many as it affords the up to 1 to 2 km to fetch water. Springs as sources of potable wa- people the convenience of obtaining water for free. Rainwater in ter occur down deep valleys at the interface between sandstone the locality is soft and slightly acidic. Pollution from particulate ridges and underlying shade beds. The stress associated with materials due to natural and anthropogenic factors presently search for water has impacts on the health of the people [15]. does not pose danger in the area of study based on the results The scarcity of water experienced by the people, especially of analysis. in the dry season, and the exorbitant price charge by the water Adequate civil and structural designs should be adhered to tanker vendors (Fig. 10) have left the people with no choice other for safe construction of concrete reservoirs. This is to avoid water than to resort to rainfall harvesting as an alternative source of shortages in the dry season. water. Water storage in reservoirs is ensured throughout the dry An education program should be carried by the health and season. water personnel in the field to educate the masses on the need to This alternative water source has numerous benefits, particu- periodically clean up the reservoirs. larly the poor rural dwellers. Its advantages include the accumu- Analysis of water samples should be carried out for physio- lation of rainwater for use by the local people, as well as ensured chemical and bacteriological parameters and adequate water availability of drinking water and water for other uses, such as treatment (chlorination) should be carried out if bacteriological for livestock and irrigation. The materials are sourced locally and tests return positive results. are inexpensive. Thus, the people are empowered economically, thereby alleviating poverty. The efforts associated with fetching water may then be diverted to additional objectives [16, 17]. Also, References there are additional dangers associated with traveling to, and collecting from sources of water [18]. 1. Pacey A, Collins A. Rainfall harvesting: the collection of rain- Harvesting rainfall could have serious health implications if fall and runoff in rural areas. London: Intermediate Technol- effective management and structural control practices are not in ogy Publications; 1986. place. Saturated air is susceptible to pollution from both natu- 2. Lee MD, Visscher JT. Water harvesting: a guide for planners ral and anthropogenic sources. Fugitive emissions include dust and project managers. The Hague: IRC International Water from soil erosion, rock crushing and building construction [19]. and Sanitation Centre; 1992. Landslides induced by rainfall are continuously occurring in the 3. Sharma PC, Sen PK. Domestic roof rainwater harvesting Agulu-Nanka gully erosion area. Sandstone boulders, cobbles, technology. In: Proceedings of Delhi Workshop on Roof Wa- and beds are crushed from quarries, graded and used for the ter Harvesting; 2001 Apr; Delhi, India. construction industries. These processes contribute to particu- 4. Kim K, Han M, Kim Y. Harvested rainwater for industrial use late materials in the air, and hence, roof rainwater may not be in power plant. In: Proceedings of the 3rd IWA International potable as it may contain pollutants. Sulfur dioxide (SO2) is emit- Conference on Rainwater Harvesting and Management; ted from combustion of sulfur containing fuel. Flaring gas in the 2012 May 20-24; Goseong, Korea.

Niger Delta region of Nigeria emits large quantities of SO2 into 5. No K, Won T. Rainwater harvesting in pacific islands. In: Pro- the atmosphere. In the atmosphere it can be further oxidized ceedings of the 3rd IWA International Conference on Rain- to sulfur trioxide (SO3) which reacts with vapour or dissolves in water Harvesting and Management; 2012 May 20-24; Gos- water to form sulfuric acid. H2SO4 is a major component of acid eong, Korea. rain. 6. Nwajide CS, Reijers TJ. Geology of the southern Anambra ba- Nitrogen oxides are highly reactive gases formed when nitro- sin. In: Reijers TJ, editor. Selected chapters on geology. Warri: gen in fuel or combustion gases is heated to temperatures above SPDC Warri; 1996. p 133-148. 650°C in the presence of oxygen. The first product, nitric oxide 7. Kogbe CA. Geology of Nigeria. 2nd ed. Jos: Rock View Ltd.; (NO) oxidizes further in the atmosphere to nitrogen dioxide 1989.

(NO2). Nitrogen oxides combine with water to form nitric acid 8. Nigerian Meteorological Agency. Nigeria climatic data: Awka.

http://dx.doi.org/10.4491/eer.2013.18.2.095 100 Rainfall Harvesting as an Alternative Water Supply

Abuja: Nigerian Meteorological Agency; c2012 [cited 2013 15. University Network for Climate and Ecosystems Change May 1]. Available from: www.nimetng.org. Adaptation Research. Water harvesting and flood risk man- 9. Standards Organization of Nigeria. Nigerian Industrial Stan- agement [Internet]. New York: University Network for Cli- dard: Nigerian standards for drinking water quality (ICS mate and Ecosystems Change Adaptation Research; c2012 13.060.20). : Standard Organization of Nigeria; 2007. [cited 2013 May 1]. Available from: www.cecar.org/groups/ 10. World Health Organization. Guidelines for drinking-water ifi/wiki/9cdf9/. quality. Vol. 1. Recommendations. 3rd ed. Geneva: World 16. Water Supply Sanitation Collaborate Council. Disaster risk Health Organization; 1984. reduction and emergency response for WASG [Internet]. Ge- 11. United Nations Environment Programme; World Health neva: Water Supply Sanitation Collaborate Council; c2009 Organization; United Nations Educational, Scientific and [cited 2013 May 1]. Available from: www.wsscc.org. Cultural Organization; World Meteorological Organization. 17. University Network for Climate and Ecosystems Change GEMS/WATER operational guide. Geneva: World Health Or- Adaptation Research. Rooftop catchments for households ganization; 1987. [Internet]. New York: University Network for Climate and 12. International Hydrological Decade-World Health Organiza- Ecosystems Change Adaptation Research; c2010 [cited 2013 tion Working Group on Quality of Water. Water quality sur- May 1]. Available from: http://www.cecar.org/groups/ifi/ veys: a guide for the collection and interpretation of water wiki/8e2e4/. quality data. Paris: UNESCO; 1978. 18. Egboka BC, Okpoko EI. Gully erosion in the Agulu-Nanka 13. Egboka BC, Mbanugoh RE, Nwogute NS, Uma KO, Okpoko region of Anambra State, Nigeria. In: Challenges in Afri can EI. Positive implications of hand-dug wells in water resourc- hydrology and water resource: Proceedings of the Harare es planning and management in a developing economy such Symposium; 1984 Jul; Harare, Zimbabwe. Wallingford, UK: as in Nigeria. Water Int. 1988;13:98-105. International Association of Hydrological Sciences; 1984. p. 14. Okpoko EI, Egboka BC. The hydrogeology of Awka and Njik- 335-347. oka local government areas of Anambra State, Nigeria: a case 19. Cunningham WP, Cunningham MA, Saigo BW. Environmen- study of a developing economy. Water Resour. J. Niger. Assoc. tal Science: a global concern. 8th ed. Boston: McGraw-Hill Hydrogeol. 1988;1:45-55. Higher Education; 2005.

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