Improved Water Management in Kankai Irrigation System. Outlines of Presentation. 1. Introduction. Introduction Contd.

Transcription

1 Outlines of Presentation Improved Water Management in Kankai Irrigation System Introduction Objectives Materials and Methods Results and Discussions Conclusions Er. Birendra Kumar Yadav 1, Er. Sanjeev Kumar Mishra 2 1 Senior Divisional Engineer, Ministry of Irrigation, Department of Irrigation, Kankai Irrigation Management Division, Nepal 2 Water Management Specialist, Irrigation and Water Resources Management Project, Department of Irrigation, Nepal 2 1. Introduction Globally, around 18% of cultivated area is under irrigation, producing 40% of all food (Schultz et al.,2005). Expansion of irrigated area with improved water management will result in increase in cropping intensity, increased overall production, productivity levels per unit of land and water, and eventually farmers gross income (KC et al., 2017). Enhanced farmers income motivates farmers to pay irrigation service fee, thereby help in sustainability of Irrigation System. Introduction Contd. Globally, both irrigated and rainfed areas have sufficient potential to produce this food requirement by improving current land and water management practices (Comprehensive Assessment of Water Management inagriculture, 2007). In national context, Irrigation water management is crucial, where irrigation structure is already developed for 81 % of the irrigable land (DOI, 2017). Therefore, irrigation water management with involvement of WUA is the prerequisite for the effective use of irrigation structure and available water sources

2 Study Area Study Area Contd. General Layout of KIS (Reach-I to Reach-IV) Study area located in eastern part of Nepal. Kankai Irrigation System (AMIS). Total command area is 8000 ha but study is conducted only in 3810 ha for spring season. Study area covers 13 secondary canals from reach I to IV. IWRMP/IMT started in KIS since Objectives of Study The Overall objective of the study is to understand operational performance of the Kanaki Irrigation System during spring season Crop Water Requirement Existing cropping pattern (crop type, area, planting and harvesting date) data were collected from WUA at tertiary level in each secondary canal. Revised cropping pattern was proposed on the basis of consultation with WUA and water availability at the Sardare (H/R) intake. Proposed pattern of staggered crop water requirements were estimated using freeware CROPWATVersion 8 model. Finally, the precipitation deficit scheme irrigation requirement on monthly basis was the output from CROPWATmodel for water balance at Sardare intake

3 Discharge, cumecs April May June July August September October November December January February March 2.2 Water Balance Reliable Supply at Sardare Intake (MIC Head) Historical record of 10 years (starting from year 2005/06 to year 2014/15) of available flow data in MIC on daily mean flow basis at Sardare Intake were modeled to estimate 50% dependable (normal) flow using freeware Rainbow Version Water Balance Water Balancing at Sardare Intake (MIC head) % reliable 50% reliable 80% reliable Delivery Schedule A delivery schedule was prepared for bulk water delivery into respective SIC under proposed rotational mode of operation. Prepared delivery schedule were further consulted and endorsed with WUA main committee at MIC level. For spring crop, group of SICs operation were scheduled based on 4 days on and 4 days off basis. Group-A consisted of (S0 to S4) and Group-B consisted of (S5 to S12) including S2 and S Calibration of Discharge Measuring structures To ensure measured bulk water delivery as per Schedule into respective SIC offtakes and MIC head. Gauge station plan with WUA was prepared. Field calibration of such structures resulting in rating table and gauge marks were then established. WUA branch committee of respective SICs was involved during field calibration process of discharge measuring structures

4 2.5 Capacity building of WUA and Gate Operators Series of on-farm and off-farm water management trainings to WUA and Gate Operators (GOs) were conducted to enhance their knowledge of and prepare for improved water management activities in partnership with WUA. 2.6 Canal Operation Plan Canal Operation Plan (COP) consisting proposed cropping pattern, water delivery schedule both for MIC and SIC, canal operation policy including job descriptions of Engineer operating MIC, WUA operating SICs & TIC and GO acting interface between Engineer and WUA were prepared for use and record. 2.7 Data preparation for assessment in spring season flow The daily mean flow data were grouped in 16 days period, as SICs operation is multiple of 4 days, to form 5 periodic groups for 80 days of scheduled operation. Volume in million cubic meter of actual water delivery (supply) and scheduled water delivery were tabulated for each period of MIC and SIC operation. No. of days of MIC and SIC canal actual operation and scheduled operation were also tabulated Canal Operation Performance Measure Water delivery performance was measured on basis as proposed by Molden and Gates, P. Ankum and M. G. Bos. a) Adequacy (P A ) : P A = V a /V s ; where P A = operation performance based on adequacy, V a = volume of actual water delivery (supplied) at an offtake over time, and V s = volume of scheduled water at an offtake over time. b) Reliability (P R ) : P R = CV of (V a /V s ); where P R = operation performance based on reliability, V a = volume of actual water delivery (supplied) at an offtake over time, and V s = volume of scheduled water at an offtake over time. 2.6 Canal Operation Performance Measure contd. c) Equity (P E ) : P E = CV of (V a /V s ); where P E = operation performance based on equity, V a = volume of actual water delivery (supplied) at an offtake over Space, and V s = volume of scheduled water at an offtake over Space. d) Schedule Efficiency (P F ) : P F = (N a /N s ) over time period where P F = operation performance based on schedule efficiency, N a = number of actual water canal operation days at an offtake over time, and N s = number of scheduled operation days at an offtake over time

5 3. Results and Discussions a) Seasonal operation performance of MIC & SICs for spring crops under Trial-1 3. Results and Discussions b) Seasonal Adequacy and Reliability performance Canal ID Mode of operation Supply volume, Mm3 Scheduled volume, Mm3 Actual operation days Scheduled operation days Schedule efficiency Adequacy Reliability Sardare S S2 Gr.-A S S S S S7 Gr.-B S S S Results and Discussions b) Seasonal equity performance Spatial equity of SICs flow over Group-A and Group-B mode of operation 3. Results and Discussions b) Seasonal Operational Schedule Efficiency Overall equity seems to be poor for both group mainly due to i) Tendency of respective SICs WUA to to get more than scheduled water, ii) GOs responsible to adjust CR in MIC and HR of respective SICs to match with scheduled supply incapacitated spatial equity & iii) series of Direct Tertiary Outlets (DTOs) offtaking from MIC is located at elevated positions. Scheduled efficiency vary from 0.8 in S7 to 1.3 in S5 under Group-B The scheduled efficiency of respective SICs however varies within 30 %. This reveals the fact that adherence by WUA to scheduled opening of respective SICs is yet to be encouraged

6 4. Conclusions and Lessons Learnt Seasonal adequacy of water delivery by Sardare Intake for groups of SICs is 1.03 (Good). However, reliability of flow variation over 5 Periods under study is 0.3 (Fair). Submergence effect, either due to CR operation or due to temporary obstruction downstream of SIC on discharge measuring Parshell flume structure has enabled GO to record more head over flow. However, structures have been calibrated only for free flow condition. Therefore, record of discharge comes out to be more than actual flow through structures. In effect, the adequacy and reliability of flow through SIC is impaired. 4. Conclusions and Lessons Learnt contd. The equity of scheduled flow distribution on Periodic basis is highly variable as equity of Group-A as 0.75 and Group-B as Therefore, target water level of respective CRs in MIC should be predetermined considering discharge requirements of DTOs for irrigation season. The operational scheduled efficiency of respective SICs varies within 30 percentages on seasonal basis. At the end of irrigation season WUAs of MIC and SIC and GOs operating MIC should be informed of the outcome of seasonal water management practice and lessons learnt should be incorporated in next year crop irrigation season in order to fine tune improved water management process through participation of WUA Gauge Reading of S4 23 6

7 नहर प रण ल स च लन त ललक (च त ध न ब ल )- (अभ य स-१) ब व नहर MIC ररच १ कम ण ड क ष त र (ह.) २७७ च न ज प रस त ववत ब ल क ष त र (ह.) Meeting with SMU/KIS, WUA & TA-Team at WUA Building about Delivery Schedule of Spring Paddy श ख /उपश ख नहर S3 व वचत क ष त र (ह.) अध यक ष फ ग ल ल त जप ररय च लन म ह Gr-A ग ट ओप र टर अव ग र ग ई व ज इन बह व (वल./.) 425 लस च ई प ल स र ल लत लस च ई प ल अन त ल लत लस च ई अवलध वह व प रलत लस च ई फ ल ह ड लब. स. ब र लब. स. ब र ल न लल./स. स. ल. 2072/11/19 6:00 ब धव र 2072/11/23 6:00 आइतब र 2072/11/27 6:00 वबवहब र 2072/12/01 6:00 मब र 2072/12/05 6:00 श क रब र 2072/12/09 6:00 म गलब र 2072/12/13 6:00 शवनब र 2072/12/17 6:00 ब धब र 2072/12/21 6:00 लबह न आइतब र 2072/11/23 6:00 आइतब र /11/27 6:00 वबवहब र /12/01 6:00 मब र /12/05 6:00 श क रब र /12/09 6:00 म गलब र /12/13 6:00 शवनब र /12/17 6:00 ब धब र /12/21 6:00 आइतब र /12/25 6:00 लबह न लबलहब र Water Management Training to WUA Water Management Training To Gate Operators 7

8 Canal Operation in SIC & DTOs Calibration S1 To-7 8