Analysis Of Rainfall Data For Drought Investigation At . - Ijlbpr

Int. J. LifeSc. Bt & Pharm. Res. 2012S R Asati, 2012ISSN 2250-3137 www.ijlbpr.comVol. 1, No. 4, October 2012 2012 IJLBPR. All Rights ReservedResearch PaperANALYSIS OF RAINFALL DATA FOR DROUGHTINVESTIGATION AT BRAHMAPURI (MS)S R Asati1**Corresponding Author: S R Asati, s r asati@rediffmail.comRainfall data of 10 years of Brahmapuri were analyzed for drought investigation, which may beused for long term planning of irrigation system in the area. During 10 years period, one droughtyear was experienced which occurred in 1972 in which the total rainfall was 801.9 mm. Acomprehensive knowledge of the trend and persistence in rainfall of the area is of great importancebecause of economic implications of the rain sensitive operations and since it plays vital role ofany agricultural and non agricultural programme. If proper and comprehensive study of variousrainfall data was analyzed, the severity and reoccurrence of drought can be known before handthus various measures can be taken to cope up with the problems and drought.Keywords: Drought month, Drought season, Rainfall, Brahmapuriannual rainfall during monsoon period, which lastsINTRODUCTIONfrom June to September i.e. four months. Themajor share of conjunctive water-need of theRainfall is the most important natural hydrologicevent and is a unique phenomenon varying bothin space and time, the rainfall distribution is veryuneven and it not only varied considerably fromplace to place but also fluctuates from year toyear. The rainfall is one of the most importantand governing factor in the planning and operationstrategies of any agricultural programme for anygiven area. As such, proper and specificinformation about the rainfall distribution patternover a period for a particular place isquintessential for proper and optimal planning ofrequisite irrigation system and cropping pattern.Indian subcontinent gets around 75% of the1country during entire calendar year is met by therainfall, which occurs in the monsoon period.There is large variation in distribution of rainfallfrom year to year. In our country swallowingfloods and thirstily droughts are the results ofspectacular extremities of the rainfall distribution.DROUGHT PRONE AREAS OFTHE COUNTRYThe Irrigation Commission, 1972 has identified67 drought prone districts comprising of 326Talukas located in 8 states having an area ofDepartment of Civil Engineering, MIET, Gondia-441614 (MS).81

Int. J. LifeSc. Bt & Pharm. Res. 2012S R Asati, 201249.73 M.ha. Subsequently, the NationalCommission on Agriculture, 1976, identified a fewmore drought prone areas with slightly differentcriteria.area is 4.3 M.ha. About 23.23% of the totalcropped area is irrigated in the drought districtsas against in all India average of 30.15%.MATERIALS AND METHODSThe erstwhile Drought Area Study andInvestigation Organization of C.W.C. set up in1978 started with 99 districts after consideringthe list of districts identified by the IrrigationCommission and also by the NationalCommission on Agriculture for carrying out furtherstudies.Because of the variety of needs of water, it is notpracticable to define a drought specifically. Aperiod of only few weeks without precipitation maybe a serious matter for agricultural operationsparticularly if the weather is hot and the humidityis low such as what prevails in our country. Onthe other hand, an irrigation project with adequatestorage may operate several months without rain.Because of our inability to define a drought interms, which are generally applicable to allproblems, there exists no general consensus forthe quantitative definition of droughts undervarying field conditions. However, in generaldrought implies of a deficiency of precipitation ofsufficient magnitude over a significantly prolongedduration. Drought as such, is a “non-event” asopposed to a distinct event such as flood.Drought requires an extended period of time todevelop. Extreme rainfalls or floods can occurseveral times in one year, whereas two or threeyears of subnormal runoff may be required todevelop a serious drought problem for basinshaving large volumes of storage. The informationon drought is a viable tool for multi objective waterresources planning problems and is implicitly ofgreat value for the incumbent planners fordesigning of storage capacity reservoirs to storethe water for contemporaneous irrigationrequirement during such drought periods. Themain cause of drought of drought experienced inall places is the insufficient non-linear rainfall.Although precipitation for a few years may beabnormal, there is usually a tendency to return tothe mean pattern. Hence, a period of abnormallyFor the studies, C.W.C. adopted the samecriteria as followed by the Irrigation commission,1972, i.e., drought is a situation occurring in anarea:1. When the annual rainfall is less than 75% ofthe normal in 20% of the years examined.2. Less than 30% of the cultivated area isirrigated.CWC adopted a smaller unit viz. Talukas fordrought identification studies instead of districtsand therefore, number of drought affected Talukaswere identified as 315 out of a total of 725 Talukasin 99 districts. Accordingly out of 108 M. ha. areaof 99 districts, only 51.12 M.ha. spread over 74districts have been considered as droughtdistricts. Thus, in comparison to totalgeographical area of the country (329 M.ha) about1/6th is drought prone.Irrigation has proved to be the most effectivedrought proofing mechanism and single biggestfactor in bringing about a large measure of stabilityin agricultural production.It would be occurred that the total geographicalarea of the drought districts is 108 M.ha, out ofwhich 81 M.ha. is culturable (75%), gross sownarea is 61.9 M.ha. (57.4%) and the gross irrigated82

Int. J. LifeSc. Bt & Pharm. Res. 2012S R Asati, 2012heavy precipitation is sooner or later balanced bya dry period so that the mean over a long intervaldoes not change appreciably. Such variations inprecipitation are of rather irregular occurrence.The interactive factors such as duration, aerialextent, intensity and probability of occurrence arealso involved unto a certain extent. While it isfeasible to estimate the maximum possible stormwhich can occur in a given basin on the basis ofmeteorological theory, it is not possible toestimate the worst possible drought conditionwhich might develop in a given area because tothe long period involved in droughts and the greatnumber of weather sequences which might leadto protracted dry periods. The only alternative,then, is to deal with the most severe dry period ofrecord.FIGURE 1: RETURN PERIODKeeping the above points in view the rainfalldata for a period of 10 years has been analyzedin the presented paper so as to study themagnitude and drought frequency in terms ofrainfall deficiency for Brahmapuri region of MS.The rainfall data for period of 10 years ofBramhapuri were collected from IrrigationDepartment. Nagpur. The 0 days average and thatof monthly and yearly rainfall were consummatelyanalyzed in the study. The above-analyzed datawere than compared to mean monthly, meanseasonal and mean yearly rainfall. On the basisof above comparison various droughts werecalculated (i.e. drought month, drought seasonand drought year). Figure 1 shows the systematicreturn periods (T) in years for the given data.Drought Season: If actual rainfall is deficient bymore than twice the mean deviation of the season(Ramdas, 1960).Drought year: If actual rainfall is deficient by 20to 50 percent (deficient drought year) and itdeficient by more than 60 percent (scanty droughtyear) (Dhar et al., 1979).RESULTS AND DISCUSSIONThe following definition of terms drought havebeen used for the analysis:Table 1 shows that minimum number of droughthave occurred one time in 24th week while themaximum number of drought were observed 6times in 34th week during the 10 years record.Drought Month: Any month receiving rainfallless than or equal to 50% of the average monthlyrainfall (Sharma et al., 1979).Table 2 shows that about 40% of rainfall occursduring the monsoon period. The average rainfallfor the post-monsoon season, summer and83

Int. J. LifeSc. Bt & Pharm. Res. 2012S R Asati, 2012Table 1: Bramhapuri (10 Years) Analysisfor Drought at Interval of 10 Days (July-october)MonthAverage Rainfall (mm)Half of Average Rainfall (mm)Number of 14.366JulyAugustSeptemberOctoberTable 2: Analysis of Monthly, Seasonal, Yearly Rainfall For 10 YearsMonth / SeasonAverage Rainfall (mm)Half of Average Rainfall (mm)Number of ember1.991.00884

Int. J. LifeSc. Bt & Pharm. Res. 2012S R Asati, 2012Table 2 (Cont.)Month / SeasonAverage Rainfall (mm)Half of Average Rainfall (mm)Number of DroughtsPost 499.15-Year1301.331041.06 (80%)1 (1972)Season520.5340%monsoon season is 56.60 mm, 244.43 mm and998.30 mm, respectively. The drought wasobserved during post monsoon season in 4 outof 10 years. It implies that there is need forirrigation for Rabi crops. While summer seasonhas drought in 3 out of 10 years, irrigation is alsoneeded for summer crops to some extent.Furthermore, no drought was observed duringthe monsoon season. Table 2 also shows thataverage yearly rainfall of Brahmapuri is1301.23mm. Brahmapuri experienced droughtin 1972 (i.e., the only year). The monsoon seasonof the drought year is shown in Table 3. As thereis only one drought year, there can be no suchsystematic interval between two successivedrought years.Table 3: Drought YearsS. No.1Drought Year1972RainfallYearMonsoon801.90653.50% of Monsoon to Yearly R.F.Timer interval between years81.49–CONCLUSIONTherefore investigation must be assured forIf proper and detailed study of various rainfall datais analyzed, the severity and reoccurrence ofdroughts can be known beforehand. Thus variousmeasures can be taken to cope up with theproblems of drought.sowing of rabi crops and for also all crop period.In a present study of Brahmapuri droughtanalysis based on 10 years was observed. Theobserved data shows that in the months of Apriland May maximum frequency of drought wasobserved and a maximum frequency of droughtoccurred in July while season wise it wasmaximum in summer and minimum in monsoon.every two year.During 10 years, there were 6 years when droughtwas expedited at Brahmapuri. The severity ofdrought was optimum in the year 1972. Therewere chances of drought occurrence once inREFERENCES1.85Asati S R (1992), “Analysis of Rainfall Datafrom Drought Investigation at Gondia (MS)”,IWWA Annual Convention at Jodhpur(Rajsthan).

Int. J. LifeSc. Bt & Pharm. Res. 20122.3.4.5.6.S R Asati, 2012Chandra H, Sharma N C and Sewaram(1992), Rainfall Data, Vol. 12, Nos. 3&4, pp.190-193.7.Sharma N C, Chauhan H S and Ram S(1979), “Probability Analysis of Rainfall forCrop Planning”, Journal of AgriculturalDhar D N, Rakheha P R and Kulkarni A K(1979) “Rainfall Study of Serves DroughtYears of India”, Drought, Vol. I, p. 314, NewDelhi.Engineering, Vol. XVI, No. 3.8.Vijay Kumar (2003), “Rainfall Characteristics of Shimla District (HP), J. of IndianWater Resources Society, Vol. 23, No. 1,Linsley R K, Kohler M A and Panlhus L H(1949), Applied Hydrology, McGraw-HillPublishing Company, ICV.pp. 1-10.9.Tripathi R P (1996), “Probability ofOccurrence of Rainfall at Pantnagar,Raj C R, Senapati P C and Lal R (1987),Investigation of Drought from Rainfall Dataat Gopalpur”,Indian Journal of SoilConservation, Vol. 15, No. 1, pp. 15-19,Orissa.Northern India”, J. of Indian WaterResources Society, Vol. 2, No. 2, pp. 7680.10. Mishra K K (1991), “Statistical Analysis ofRainfall Data”, IEC (O) Journal CV, Vol. 71.Ramdas L A (1960), “Crop and Weather inIndia”, ICAR, p. 127, New Delhi.pp. 177-180.86

The rainfall data for period of 10 years of Bramhapuri were collected from Irrigation Department. Nagpur. The 0 days average and that of monthly and yearly rainfall were consummately analyzed in the study. The above-analyzed data were than compared to mean monthly, mean seasonal and mean yearly rainfall. On the basis of above comparison various .