SPATIAL AND TEMPORAL VARIATION OF IRRIGATION WATER QUALITY IN WATARI IRRIGATION SCHEME

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1 SPATIAL AND TEMPORAL VARIATION OF IRRIGATION WATER QUALITY IN WATARI IRRIGATION SCHEME D.Mohammedand U. A. Garba Department of Agricultural Engineering, Kaduna Polytechnic,Kaduna I. Audu Department of Agricultural Engineering, University of Maiduguri, Maiduguri or Abstract Irrigation water from Watari irrigationscheme in Kano state Nigeria was assessed to determine its suitability for irrigation and to determine the spatial variation of water quality parameter at different point of the dam.sample collection was done in the month of April 2013, November 2013, and February At each period, 12 samples were collected.the parameters analyzed are ph, Electrical Conductivity (EC), Sodium, Potassium, Calcium, Magnesium, Carbonate, Bicarbonate, Boron, Chloride, Sulphate, nitrate nitrogen and ammonium nitrogen. Sodium Adsorption Ratio (SAR), Residual Sodium Carbonate (RSC), Exhangeable Sodium Percentage (ESP) and Permeability Index (PI), were also calculated. Result obtained has shown that the water is suitable for irrigation with occasional leaching to reduce sodium hazard. The PI Predicts infiltration problem but the SAR and RSC values have shown that the water is of good quality for irrigation. The PI ranges from %, the EC ranges from ms/cm, the SAR ranges from Statistical analysis using Generalized Linear Model (GLM) has shown significant variation of parameters between points and period at p<5% and some parameters have shown insignificant difference. It was recommended that management practices such as leaching, application of amendments such as gypsum, growth of tolerant crops is necessary if the water is to be used for irrigation to avoid impoverishment of soil structure and that a system responsible for monitoring surface water quality must be put in place to address the issue of water pollution related to human activities and indiscriminate discharge of effluent into the river to avoid pollution of reservoirs. Keywords: Spatial, water, quality, variation and parmeability Introduction In some areas sufficient rainfall is available for crop growth but in other areas, the amount and timing of rainfall is inadequate to meet moisture requirement of crops. The need to feed and improve the standard of living of the everincreasing human population led to the introduction of the irrigation schemes by Nigerian governments in the last 20 years.this has facilitated the cultivation of the same land twice or more in a year and has improved the famers standard of living (Shanono et, al,2012). Kano has a tradition of irrigated agriculture and is reckoned as the leading hydro agricultural state in Nigeria. Small scale irrigation on Fadama areas has supported crops that require all year round water. Kano has the largest irrigated area in the country with more than 3 million hectares of cultivated land. It is the largest and most populous city in Nigeria. The population of the city is estimated to over 10 million during the 2006 national population census (Dan azumi and Bichi, 2010). In an attempt to provide enough food for the growing population in the state, effort has been made by the state government to intensify agricultural production through irrigation. This resulted in the establishment of Kano River Irrigation Project (KRIP). Kano River irrigation Project is a large scale agricultural project in Nigeria with focus on irrigation. The project commenced in 1969 with construction of Bagauda dam supplying Kadawa irrigation sector as a pilot Scheme. Other dams such as Watari,Challawa gorge, Jakara, Gari, Kafinchiri etc. are also used for irrigation in Kano state. Watari Irrigation project was one of the public irrigation schemes developed by Kano State 337

2 government aimed at increasing crops production and livelihood of rural farmers (Shanono et, al,2012).the Watari scheme is located about 100 kilometers north east of Kano city. It is situated in the Sudan Savanna agro-ecological zone. The scheme is situated in an inland river valley, and covers the valley bottom and parts of slopes on both sides. Heavy clay soils with high organic matter content dominate the valley bottom (natural swamps, which are flooded during the wet season), but lighter textured soils (sandy loam) are found in the higher positions.rice is mainly produced for cash, and production is sold individually to traders or on the market. Women are mainly involved in seedling uprooting, transplanting, weeding and winnowing (Kebbeh et,al 2003).. Knowledge of water quality is critical to understanding of what management changes are necessary for long term productivity (Bauder etal, 2013). This research assesses and compares water quality in reservoir and different sectors of watari irrigation scheme with a view to apply the findings inthe use and management of irrigation water within the scheme. The research also studied the possible change in water quality from the reservoir to tertiary canals due to various human activities such as washing, bathing, fishing, watering of livestock, and the effect of insecticides, pesticides, fertilizer etc. which gets into the canals, and reservoir through runoff water. Material and methods The Study area Watari dam supplies a medium scale irrigation project located on the slopes of Watari river valley in Bagwai Local government which is 18 km from Bichi. It is located at Latitude of N and Longitude E in the valley of Watari River, a tributary of Challawa River.Heavy clay soils with high organic matter content dominate the valley bottom (natural swamps, which are flooded during the wet season), but lighter textured soils (sandy loam) are found in the higher positions (Kebbeh et, al2003). The net irrigable area is 690 ha and the command area consists of five sectors which are irrigated through northern outlet which convey water to 12km main canal. Sector 8 which is the pilot scheme is irrigated through the Southern outlet while the sixth and seven sectors are still under construction.the metrological data obtained from the area indicated an average relative humidity of 33.5% during the dry season, and 74.5% for the wet season. And average minimum temperature of 14 0 C and an average maximum temperature of C. It also has a monthly average precipitation of 66.5mm during the wormwet season per month (Karaye, 2002 as in Shanono, 2012). Sample collection Samples were collected in plastic containers from the reservoirs and within primarycanal in pilot scheme, secondary canal in sector II and tertiary canals in sector V of scheme. At each point of collection; three (3) samples were collected to ensure accuracy by replication. The collections were done in the months of April 2013 (late dry season), November 2013 (beginning of Dry season) and February 2014 (mid dry season).a total of thirty six (36) samples were collected.the plastic bottles used for the sample collection were washed with detergent and rinsed 3 times with distilled water and then with the sample water. Laboratory works The ph was determined by electrometric method with ph meter M200, the electrical conductivity was determined with conductivity meter 4071, Sodium and potassium were determined using flame photometer 400,Volumetric method was used for the determination of Chloride, Carbonate and Bicarbonate magnesium and calcium by complexometric titration, boron by Azomethine-H method, nitrate and ammonium nitrate by Nessler s Calorimetric Method.The test procedure is in accordance with APHA standard method for the examination of water and waste water -20 th editions. Calculation of some parameters from laboratory result The sodium adsorption Ratio (SAR) was calculated from the values of sodium, calcium and magnesium from the following relationship (Michael,2008): 338

3 SAR Ca Na Mg eq 1 The values of the elements in mg/l were converted to meq/l using the equations below: mg / l Meq / l eq. wt eq 2 at. wt eq. wt valency..eq 3 The exchangeable sodium percentage (ESP) was also calculated from this expression: Na ESP x Na Ca Mg K..eq 4 RSC CO 3 HCO Ca Mg eq 5 The permeability index was calculated as follows: (Dhirendia,2009). Eq 6 Statistical analysis Generalized Linear Model (GLM) procedure in Statistical Package for the Social Science (SPSS) was used in the analysis of data. GLM of two way Analysis of Variance (ANOVA) was used to analyze parameters between time and points within the dam. The mean of each parameter was compared using Least Significant Difference (LSD) post Hoc test. Result and discussion The result of laboratory analysis for different parameters was recorded and the mean values of these parameters obtained from the analysis of variance for each reservoir are presented in table. The values of Sodium Adsorption Ratio (SAR), Residual Sodium Carbonate (RSC), Exchangeable Sodium Percentage (ESP) and Permeability Index were calculated and presented also in the table. 3 Spatial variation PI Na HCO 3 2 Na Ca Mg 2 100% Table 1: Variation of water quality parameters at Watari Dam Parameter Unit Resrvoir Pri. Canal Sec. canal T. Canal SE LOS ph c 7.06a 6.98b 7.04ab * EC ms/cm 1.14b 1.52a 1.55a 1.50a * HCO 3 mg/l 25.39c 26.84a 26.04b 26.95a * Boron mg/l 0.20b 0.19b 0.20b 0.23a * Chloride mg/l 26.32a 25.85b 26.60a 25.79b * NO 3 -N mg/l 7.38a 7.22b 7.26b 7.30ab 0.03 * NH 4 -N mg/l NS Sulphate mg/l 3.02d 3.37c 4.23b 4.52a 0.09 * Note: NS (Not Significant), * significant at 5% 339

4 Means followed by same letter in same row are not significantly different from each other. Table 1 and figure 1 shows spatial variation of irrigation water quality at Watari dam.in the scheme all parameters varied significantly between locations except ammonium nitrate and are all within acceptable limit. The ph at all location is within the normal range.the ph of irrigation water is not an accepted criterion of water quality because it tends to be buffered by soil and most crops can tolerate a wide range of ph. However, the normal ph range of irrigation water is (Ayers and Westcots, 1976).The EC ranges from 1.55mS/cm at secondary canal in sector II to 1.14mS/cm at reservoir. An EC of 1.14mS/cm is above the threshold value of 1.0dS/m for onion, carrot and bean but all other crops grown in the scheme have their threshold value greater than the highest mean EC value recorded in the whole sectors. Therefore, when tomatoes, maize, sugarcane, wheat, cotton, cowpea, cucumber etc. are grown, their maximum production potential can be achieved as their threshold value is higher than highest EC observed in the scheme Resrvoir Primary Canal Sec. canal Tert. Canal 5 0 ph EC HCO3 Cl NO3 NH4 SO4 Figure 1: Bar Chart Showing Spatial Variation of Water Quality in Watari Dam Although the nitrate and ammonium are within acceptable limit, there is moderate restriction on the use of water as the value of nitrate is greater than 5mg/l and nitrogen sensitive crops such as grapes and sugar beet will be affected by this concentration and fortunately they are not grown in the scheme. Temporal variation In Watari dam, at all periods the parameters are within acceptable limit for irrigation. The ph ranges from7.60 in November to 6.14 in april as shown in table 2 with significant differences between the periods. Shanono et,al recorded a ph range of within the Watari scheme.dike et al. (2013) reported ph values as high as 7.32 and 7.35 in February and October respectively in Jakara dam. 340

5 Table 2 Temporal Variation of Parameters in Watari Dam Parameters Unit Apr-13 Nov-13 Feb-14 SE LOS ph 6.14c 7.60a 7.22b 0.02 * EC ms/cm 1.22c 1.91a 1.16b * HCO 3 Mg/l 31.32a 22.52c 25.08b * Boron Mg/l 0.22a 0.19c 0.21a * Chloride Mg/l 26.92a 22.82c 26.69b * NO 3 -N Mg/l 7.89a 6.82c 7.16b * NH 4 -N Mg/l 1.31a 1.31a 0.87b * Sulphate Mg/l 3.38b 3.70b 4.18a * Note: NS (Not Significant), * significant at 5% Means followed by same letter in same row are not significantly different from each other. EC mean values have shown significant difference at P< 5% at allperiods. The highest value of EC (1.91mS/cm) was recorded in November and the lowest value of 1.16mS/cm was observed in February. This implies slight to moderate restriction in in the use of this water for irrigation. Field and vegetable crops and their threshold EC which are usually grown under irrigated condition in this schemes are maize (1.7dS/cm), cotton (7.7dS/cm), rice (3dS/cm), sorghum (6.8dS/cm), soybeans (5.0dS/cm), sugarcane (1.7dS/cm), wheat (6.0dS/cm), bean (1.0dS/cm), carrot (1.0ds/cm), cowpea (4.9dS/cm), cucumber (2.5dS/cm), Onion (1.0dS/cm), pepper (1.5dS/cm) and Tomatoes (2.5dS/cm) (FAO,2002) With crops like potatoes, corn, onion, beans, cowpea and wheat no yield reduction will be recorded and maximum production potential of crops irrigated with this water can be achieved. The EC at all periods have exceeded the threshold values of carrot, bean, onion etc. The water is of high salinity based on the United State Soil Laboratory classification. Damage to plants with low tolerance to salinity will occur. Plant growth and quality will be improved with excess irrigation for leaching and or periodic use of low salinity water and provision of good drainage. Successful use of water with EC above 0.75dS/m depends upon soil condition and tolerance to salinity (Camberato, 2001)Shabalala et.al, 2013 reported EC range of 3-16mS/cm in Bonsma dam of south Africa and submitted that the water is within the limit for domestic use April November February 5 0 ph EC HCO3 Cl NO3 NH4 SO4 Figure 22: Temporal Variation of Parametersat Watari dam No detectable amount of carbonate (CO 3 ) was observed in all the month, there is no restriction on the use of water for irrigation with respect to bicarbonate composition as all the values are less 341

6 than 1.5meq/l. The effect of bicarbonate is more pronounced on sprinkler irrigation when the concentration exceeds 1.5meq/l whereas in the entire irrigation scheme in Kano, surface method of irrigation is mostly practiced. Chloride concentration in all reservoirs is lower than 70mg/l and value below this concentration is generally safe for all plants.nitrate nitrogen mean values at points is above the usual value of 5 mg/l in fresh water except the late dry season value recorded in reservoir. Mean values of ammonium nitrate greater than 1mg/l wasalsoobserved in most locations. Table 3: Calculated parameters S/No parameter Rvr Pri. Canal sec. canal tert canal 1 SAR RSC ESP PI Residual Sodium carbonate (RSC) at all points.is less than one. Adamu, 2012 recorded an RSC values ranging from 8.00 to in the sheme and reported that water in some of the sectors is not suitable for irrigation. According to U.S. Salinity Laboratory, an R.S.C. value less than 1.25 meq/lit is safe for irrigation. A value between 1.25 and 2.5 meq/lit is of marginal quality and value more than 2.5meq/lit is unsuitable for irrigation (Dhirendra, 2009). Based on RSC, the water is suitable for irrigation as all the values of RSC are less than 0 as shown in table 3 above, there will be no RSC associated problem with water in all the schemes. The permeability index (PI) of water in all reservoirs suggest permeability problem because the mean values are less than 75. Sodium Adsorption Ratio (SAR) means values are generally less than 1 Adamu, 2013 reported SAR ranging from 6.87 to in Watari irrigation scheme. The lower SAR range of reported by Shanono et.al, 2012 and range observed in this research might be due to lower value of calcium and magnesium compared to sodium at period of sampling. Conclusion Water quality parameters in Scheme were determined in April, November and February. The parameters varied significantly at various points within the Scheme and in different period of the season. Most Parameters varied significantly from one point to another at p<5% and few have shown insignificant difference between points. The ESP in all locations is less than 15%. Residual sodium carbonate has shown that there will be no infiltration related problem but the permeability index suggestproblem.based on the result obtained, all crops can be grown effectively in the scheme. Management practices such as leaching, gypsum application, and choice of tolerant plants may help to maximize yield when crops are to be irrigated with the water. Since the parameters varied significantly water should be tested occasionally to assess salt build up. References Adamu G. K (2013): Quality of Irrigation Water and Soil Characteristics of Watari Irrigation Project, American Journal of Engineering Research,Vol 02. Akindele E.O, Adeniyi I,F and Indabawa I.I (2013): Spatio-temporal Assessment and Water Quality Characteristics of Lake Tiga, Kano Nigeria, Research Journal of Environmental Earth Science 5 (2),

7 Ayers R.S and Westcots D.W (1997). Water quality for Agriculture: Irrigation and Drainage Paper 29, Food and Agriculture Organization of the United Nation, Rome. Bauder T.A, Waskom,R.M; Sutherland,P.L; and Davies J.G (2013). Irrigation Water quality Criteria, Colorado State University, Fact sheet No Bichi, M. H (2013). Management of Industrial Effluents: A Review of the Experience in Kano, Northern Nigeria, International Journal of Advance Research Vol 1, issue 4, Dan zumi S. and Bichi M.H (2010). Industrial Pollution and Heavy Metals Profile of Challawa Rivers in Kano, Nigeria. Journal of Applied Science in Enviromental Sciences, Vol 5, Number 1:23-29 ISSN Dhirendra M.J, Kumar A. and Agrawal N (2009). Assessment of Irrigation Water Quality of River Ganga in Heridwar District, Rasanyan Journal of Chemistry, Vol2 No2 (2009), ,ISSN; Dike N. I, Ezealor A,U, Oniye S.J and Ajibola V.O (2010). Nitrate and Phosphate level of River Jakara, Kano State,Nigeria,Science World Journal, Vol 5,No3,2010 ISSN Dike N. I, Ezealor A,U, Oniye S.J and Ajibola V.O (2013). Pollution Studies of River Jakara in Kano Nigeria Using Selected Physico-Chemical Parameters, International Journal of Research in Environmental Science and Technology, ISSN FAO (2002). Agricultural Drainage Water Management in Arid and Semi-arid Areas, FAO drainage paper61, Rome. Shabalala A.N, Combrink L, McCrindle R (2013). Effect of Farming Activities on Seasonal Variation of Water Quality in Bonsma Dam, Kwazulu-Natal, South Africa Journal of Science2013:109 (7/8), Vol 109. Taiwo A.M,Olumiji, O.O, O. Bamgbose and Arowolo T.A(2012).Surface Water Quality Monitoring in Nigeria.Situational Analysis and Future Management Strategy, Voudouris (Ed): Water Quality Monitoring and Assessment Wikipedia Encyclopedia (2013). Kano. http.en.wikipedia.org/wiki/kano. Last Modified April,