Identification of Various Drought Characteristics for the Dahod District of Gujarat
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Agricultural Engineering Today Identification of Various Drought Characteristics for the Dahod District of Gujarat Sharad Kumar Namdev (LM 11301)1 and Munish Kumar Pandey2 1Assistant Professor, Agricultural Engineering, School of Agriculture, ITM University Gwalior, Madhya Pradesh (India)-475001 2Assistant Agriculture Engineer, Department of Farmer Welfare & Agricultural Development, Narshingpur, Madhya Pradesh (India)-482004 Corresponding author's email: [email protected]; [email protected] Date of submission: 8.5.2017 Date of acceptance: 7.08.2017 ABSTRACT Drought is one of the most serious problems for human society and ecosystem from climate variability. Although, it does not affect through sudden events such as flood and storms but it is considered as the world’s costliest natural disaster, causing on an average $6–$8 billion in global damages annually and collectively affecting more people than any other form of natural disaster (Wilhite, 2000). The National Commission on Agriculture (MOA, 1976) identified 74 drought prone districts located in 13 states of India. Gujarat is one of the most drought prone areas of India wherein eleven districts of the state are in arid regions including Dahod region which is one of most backward districts. Dahod region is characterized by agriculture based livelihood income and faces frequent droughts due to delayed or little rainfall. Therefore, the present study was carried out to determine hydrological and agriculture panorama of drought in 7 Talukas of Dahod district. It was found that average annual rainfall in Dahod district varied from a minimum of 690 mm at Garwada to a maximum of 847 mm at Limkheda with the average annual rainfall of 833 mm. The average drought frequency in Dahod district varied between 1 in 5 years at Devgarh, 1 in 4 years at Jalod and 1 in 3 years at Limkheda, , Garbada, Dhanpur, and Fatepura talukas. It was also concluded from annual departure analysis that severe drought condition were seldom experienced in Dahod town but many of the talukas in the district experienced moderate drought situation for number of years. Key words: Dahod district, Annual rainfall, Drought frequency, Departure analysis, Drought severity INTRODUCTION Meteorological drought, (ii) Surface water drought, Drought is a temporary aberration unlike aridity (iii) Groundwater drought and (iv) Soil - water which is permanent feature of climate. Seasonal drought. The National Commission on Agriculture aridity also needs to be distinguished from drought. in India defined three types of droughts, namely Thus, drought is a normal, recurrent feature of meteorological, agricultural and hydrological climate and occurs in all climatic regimes (Capodici droughts. Meteorological drought is defined as et al. 2008). Drought results from long continued a situation when there is significant decrease dry weather and/or insufficiency of rain which from normal precipitation over an area i.e. more causes exhaustion of soil moisture, depletion of than 25 % (Shouraseni et al. 2004). Agricultural underground water supply and reduction of stream drought occurs when soil moisture and rainfall are flow. Drought is frequently defined according to inadequate during the growing season to support disciplinary perspective and Bandyopadhyay, 1988 healthy crop growth to maturity and causes crop listed mainly four types of droughts, namely (1) stress and wilting (Rawls et al. 1993). Hydrological 52 Vol. 41(4), 2017 drought may be a result of long term meteorological data of all the 7 talukas of Dahod district was collected droughts which result in the drying up of reservoirs, from the office of Survey & Land Records, Gujarat lakes, streams and rivers, and fall in groundwater for analysis of drought years. The taluka-wise rainfall level. In fact, meteorological drought precedes the distribution is given Table 3. agricultural and hydrological drought (Svoboda et Annual rainfall departure: The departure analysis al. 2002). The agricultural and hydrological drought of annual rainfall was carried out to identify the need not occur simultaneously but occur subsequent drought years, its frequency and severity based to a meteorological drought. Agricultural drought on the rainfall deficit from normal rainfall values. is specifically concerned with cultivated plants, as Generally a year is considered as drought year if opposed to natural vegetation (Dracup et al. 1980). the total amount of annual rainfall over an area is Owing to the continuous need of adequate water deficient by more than 25% of its normal value. The by plants, agricultural drought may set in rapidly, annual rainfall departure analysis comprises of the and can similarly terminate suddenly. The National following steps: Commission on Agriculture (MOA 1976) identified 74 drought prone districts located in 13 states of India. i. Determine the mean (Xm) for a set of annual Gujarat is one of the most drought prone areas of rainfall data. India wherein eleven districts of the state are in arid regions including Dahod region which is one of most Table 1: Irrigated area of Dahod backward districts. Dahod region is characterized by agriculture based livelihood income and faces Irrigation water availability and Area (‘000 ha) frequent droughts due to delayed or little rainfall. use Therefore, the present study was carried out to Net irrigated area 80.9 determine hydrological and agriculture panorama Gross irrigated area 94.8 of drought in 7 talukas of Dahod district Rainfed area 143.37 MATERIALS AND METHODS Table 2: Major soils in Dahod and covered area Dahod is most backward district in Gujarat state. The district has 7 talukas with 696 villages. The Major soils Area (000’ Percent (%) of total geographical area of the district is about 3.7 ha) total geographical area lakh hectares. The climate of district is usually hot Hilly light soils 155.9 42.7 and maximum temperature is about 44°C and the minimum temperature is about 6.5°C, Therefore, Sandy loam 39.2 10.7 shallow soils district was considered as rainfed area. With an Deep black 31.6 8.6 average rainfall 738 mm, Dahod district has faced shallow soils drought condition many times due to delayed rain. Therefore, a study was carried out to determine Table 3: Taluka wise annual rainfall distribution in hydrological and agriculture panoramas of drought Dahod district in terms of onset, severity and end of droughts (Le Houerou, 1996). The Table 1 shows the irrigated area Mean Name of annual Standard and Table 2 shows major soils in Dahod. S.N. C.V. (%) Talukas Rainfall deviation Identification of drought years:Drought has many (mm) facts and it always starts with lack of precipitation. 1 Dahod 738 262.308 35.45 Therefore, it leads to different types of droughts 2 Jhalod 804 293.463 36.5 i.e. Meteorological, Agricultural, Hydrological, etc. 3 Limkheda 847 339.058 40.03 According to the Indian Meteorological Department 4 Devgarh 726 277.575 38.23 (IMD), an area is considered to be drought affected 5 Garwada 690 235.198 34.08 if it receives total seasonal rainfall less than 75% of 6 Dhanpur 820 330.277 40.27 normal rainfall (Appa Rao, 1986). The annual rainfall 7 Fatepura 791 342.451 43.29 53 Agricultural Engineering Today as to interfere with the other phases of regional economic activities. The daily rainfall data of Dahod ͳ was analyzed for rainfall departure analysis and ൌ performed on the basis of annual and seasonal ൌͳ ii. Calculate departure (Di) by subtracting the rainfall. The distribution of annual rainfall in various mean (Xm) from the individual annual rainfall talukas of the Dahod district in Gujarat is given in data (Xi). Table 3. The annual rainfall in Dahod district varied between a minimum of 690 mm at Garwada to a maximum of 847 mm at Limkheda with the average annual rainfall of 833 mm. iii. From resulted ൌ departure − (Di), the departure percentage (D%) is calculated as follows The distribution of annual rainfall and standard deviation in various talukas of the Dahod district is given in Table 4. The standard deviation in Dahod town, Jalod, Limkheda, Devgarh, Garwada, Ψ ൌ ∗ ͳͲͲ Dhanpur and Fatepura was 262.308, 293.463, However, in this study the drought severity has been 339.058, 277.575, 235.198, 330.277 and 342.451 classified on the basis of percentage deviation from respectively, Fig. 1. the normal rainfall into three severity classes namely (a) mild drought occurrence when the percentage Identification of drought years: The departure annual rainfall departures lied between -20% to analysis of annual rainfall was carried out to identify the drought years, its frequency and severity based -25%, (b) moderate drought occurrence when the percentage annual rainfall departures lied between on the rainfall deficit from normal rainfall values. -25% to -50% and (c) severe drought where departure The positive departure is the sign of wet condition percentages was greater than -50%. The departure whereas the negative departure is the indicator of analysis of annual rainfall was performed for all the 7 drought condition. Drought severity was also arrived at, based on the criteria as: -20% to -25% for the blocks of Dahod district and subsequently the drought mild drought year, -25% to -50% for a moderate years were identified. drought year and greater than -50% for a severe Seasonal rainfall departure: The Dahod district drought year. From the rainfall departure analysis, receives 90% of its rainfall from the monsoon during the drought years were identified along with the mid June to end of September. Since agriculture is average frequency of drought and are presented in the main livelihood of the local population and also Table 5. The annual rainfall departure for the various as most of the cultivated area is rainfed, analysis of Talukas in Dahod district are given in Fig. 2 to Fig. 8. seasonal rainfall is vital. The dry spells which occur On the basis of annual departure analysis, it was within the rainy season causes severe stress on observed that the total drought (moderate or severe) agriculture crops and affect the normal life pattern years faced in Dahod, Jhalod, Limkheda, Devgarh, of the region.