Rainfall Trend analysis for semi arid region

Rainfall Trend analysis for semi arid region

1. Wet and dry spell characteristics of semi-arid region, Western Maharashtra, India Kamlakishor R. Atal Pune Institute of Computer Technology, Pune Email: [email protected] Presentation @ 36 th IAHR 2015 Congress, 28 June -03 July 2015 , The Hague, Netherlands

2. Water stress in Semi-arid & Arid regions are attributed to uncertainty of rainfall amount, time and place dry spell during crop growth period reduced crop growth and drought conditions Poorly managed water infrastructures or their non-availability demand exceeds availability ground water extraction exceeds recharge, leading to quality and quantity issues Climate change could adversely enhance the stress conditions. Water sharing issues – upstream and downstream Government’s have invested in the water harvesting and distribution systems in the past 4 or 5 decades, in achieving the food and water security 9

3. Prior knowledge of the dry and wet spell analysis would be beneficial to minimize unexpected damage due to long dry spells and to have effective and efficient planning for various stake holders of Yerala River Basin. Methodology Create an inventory (Spatial) of rainfall: Yearly , monthly, weekly and daily Assess of rainfall trend using Mann Kendall Non-Parametric Test Evaluate annual, monsoon and non monsoon rainfall and spatial and frequency distribution of rainfall intensity Weekly rainfall during the crop growth period of June - October (24th to 46th Meteorological week) was calculated Use multi-criteria analysis in evaluation 8 Objective

4. Yerala River Basin – (Krishna River System) 7

5. River basin located in the semi-arid region, having rain-shadow region as their catchment. River flow is seasonal Rainfall – 400mm (1998 ) – 1034mm (2006) Drought situation - once in 3 years 10 Rain gauge stations – 4 inside and 6 close to periphery 6

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7. Weekly Rainfall 1998 JUN 1-7 JUN 8-14 JUN 15-21 JUN 22-30 JULY 1-7 JULY 8-14 JULY 15-21 JULY 22-31 AUG 1-7 AUG 8-14 AUG 15-21 AUG 22-31 SEP 1-7 SEP 8-14 SEP 15-21 SEP 22-30 OCT 1-7 OCT 8-14 OCT 15-21 OCT 22-31 DAHIWADI 9 19 23 13 11.2 10.8 13 108 28 82 134 35 19 79 59 87 14 ISLAMPUR 31 9 20 40 127 84 36 61 15 44 59 13 9 1 18 120 98 11 KADEGAON 30 5 29 25 58 3 45 2 15 21 94 11 15 49 61 55 3 KARAD 37 5.04 0.32 54.11 26.11 60.02 6.4 58 8.38 18.96 25.48 96.79 13.76 17.1 59.2 66.16 58.69 7.06 KOREGAON 14 4.2 13.4 75 26 49 3.6 103.4 6 13.6 22.2 48.4 112.9 19.4 12.6 28.5 93 124.2 13.2 MIRAJ 6.1 29 29.9 15.3 33.1 50.2 26 6.8 8.6 8 35 17.9 6 2.6 41.5 121.8 71.6 8.7 PALUS 19 27 7 33 11 43 40 99 5 33 14 45 50 37 3 25 112 69 34 TASGAON 19 27 7 33 11 43 40 99 5 33 14 45 50 37 3 25 112 69 34 VADUJ 9 19 23 13 11.2 10.8 13 108 28 82 134 35 19 79 59 87 14 VITA 52 5 18 37 13 20 55 59 2 27 9 77 75 31 14 80 94 71 9 2003   DAHIWADI 3 12 16.4 3 1 4.5 4 6 42.1 17 ISLAMPUR 32 35 3 3 3 29 4 7 10 8 6 3 21 48 KADEGAON 2.06 22.03 51 4 2.01 7 28 6 6 12 2 8 16 78 KARAD 9.8 28.6 55.9 9.6 29.5 11.3 87.14 9.28 8 10.22 18.87 4.12 1 0.2 10.23 123.1 KOREGAON 98.4 34.2 11 9.4 13.4 61.4 14.4 10.4 2 38.8 9.8 6.2 1.2 26.2 3 MIRAJ 15 4 14.6 3.1 10.3 1.1 4.3 0.2 10 14.7 0.1 30 114.4 31.2 PALUS 11 40 13 2 2 16 13 1 5 4 3 5 8.6 29 TASGAON 14 7 3.4 3.8 4.2 12.2 15.4 4.4 5.2 9.3 1 20.2 13.8 34.8 VADUJ 45 9.8 7.5 3 7.5 1 14.1 1 2 7 1 15.2 21.1 3.1 6.3 VITA 12 26 64 5 15 2 14 9 3 1 6 1 53 15 56 1 Rainfall (mm) 0-25   26-50 51-100 101-150 151-200   >200 Crop Growth Sowing Vegetation Growth Flowering Grain Formation Harvesting Crop Growth Sowing Vegetation Growth Flowering Grain Formation Harvesting Supplementary Irrigation Requirement 4

8. Dry spell – Number of days between one rainfall event to another 3

9. Dry and Wet Spells Rain Gauge Station Maximum duration of Dry Spell (days) Continuous rain (Wet Spell (days) Total no. of dry Spell ( June – Oct) Year Dahiwadi 26 5 4 2011 18 5 5 2009 Islampur 20 5 3 2003 10 18 1 2005 Kadegaon 17 4 6 2003 21 32 4 2006 Karad 7 20 3 2003 9 19 4 2005 Koregaon 14 10 3 2003 9 15 3 2005 Miraj 21 4 5 2003 17 22 4 2006 Palus 33 9 6 2002 11 8 2 1998 Tasgaon 24 4 4 2003 11 7 2 1998 Vaduj 21 4 5 2003 23 8 5 2009 Vita 19 4 6 2003 16 8 2 1998 Significance Supplementary irrigation Quantity of water required Effect on crop growth Observed Maximum Dry S pells 33 days in Palus (2002) 17 days in Kadegaon (2003) 19 days in Vita (2003) 9 2

10. Conclusions Frequent dry spells or non-uniform spatial distribution or delay in arrival of monsoon Initiation of the cultivation activities (land leveling or sowing) is deferred or blind decisions (without knowledge) are taken and executed leading to crop failure due to insufficient water . Spatial and temporal variability of rainfall for 1998 to 2011 indicate no systematic trend and correlation between the rain gauge stations Dry spell of the monsoon was used in the identification ground water supplementary irrigation . Rainfall data indicate a wide variation in the distribution of yearly, monthly and weekly rainfall in terms in space and time. The rainfall represents of local pattern and not regional. Agriculture planning with this spatial and time uncertainties, leads to greatest risk in agriculture. 1

11. Thank you Observations and suggestions if any