SPATIAL DISTRIBUTION AND GIS MAPPING OF SHALLOW TUBEWELL IRRIGATION SYSTEM
5.3 DATA ANALYSIS, RESULT AND DISCUSSIONS .1 Spatial Distribution of Shallow tube wells
5.3.2 Changing of STWs location and command areas in Saitapara Mouza
The STW irrigation business dynamics was changed in the study area like any other business.
Therefore, changing phenomenon of STW locations and corresponding command areas also took place (Figure 5.3). The changing pattern STW location / position and STW coverage area are studied in this section only of Saitapara mouza in details. The command area were affected by partnership, shifting from DOS to EOS, micro variations in topography, soil type, gradient and availability of low lying beels . STW location have been changed little bit over the last 20 years since 1997 (Figure 5.3). If we explain/review the Figure 5.3, then we can see different scenario in the study area, such as some STWs location, ownership and command area have been changed and some location was unchanged but command area was changed or some location was unchanged but ownership was changed etc. However, a case study was described below where was shown the slope profile (Figure 5.4) between two adjacent STW through Digital Terrain Model (DTM)
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Figure 5.3: Comparison of command areas under different STWs among 1997, 2007 and 2017.
C/A in 2017 TW Locations in2017
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Plot-wise land use is prepared from mauza map of 1997 (Mandal, 1997) and also plot-wise land use map of 2007 (Hossain and Moududi, 2009) and plot-wise land use map of 2017 is prepared from the field survey of January 2017. Here it is needed to mention that land use pattern of 2007 and 2017 were the same. There is no significant change found in land use (Figure 5.5) of the Saitapara mauza over last twenty years since 1997. Only two small plots went under irrigation area in 2007, which were previously covered by sand.
Case study: Mr. Akbar and Mr. Fazlu were the STW owner and their command areas were adjacent. Akbar was known as a bad tempered person and thus he had no good relationship with the farmers (water buyers). He was selling water but did not listen to complaints from the water buyers. So farmers moved to other STWs day by day. Finally he had to stop his STW irrigation business as no body wanted to buy water from his STW. On the other hand, Mr.
Fazlu was in disadvantages position in terms of land elevation variations i.e. the command area of Akbar was in the lower elevation rather than of Mr. Fazlu (Figure 5.3 and 5.4). Due to gravity force, naturally irrigation water seepage / passed from upper elevation to lower elevation. Therefore, Mr. Fazlu had to more irrigate due to water loss. But when Mr. Akbar stopped his irrigation business, then Mr. Fozlu has increased command area comparatively less fuel cost from 4.11 to 9.56 hectares by utilizing the land slope from 1997 to 2007 respectively.
Figure 5.4: Digital Terrain Model (DTM) showing the slope profile between two STW.
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Figure 5.5: Landuse pattern of Saitapara mauza since 1997 5.3.4 Cropping Pattern Analysis of Kurmurshi Mouza
In Kurmushi mauza, Mortuz Ali has a STW covering about 4.4 hectares of land consisting 56 plots. There are seven different cropping patterns (Figure 5.6) found in 2016 cropping year in such a small command area. The main cropping patterns were Boro-B.Aman-Mustard and Boro- T.Aman-Mustard in the study area. The variations are due to the different land elevations, where the western part of the command area is higher and the eastern part is lower. Vegetables are grown on higher lands and Boro-Aman are grown on lower lands. Even where Aman is grown, comparatively higher lands are used for growing transplanted Aman and lower lands for broadcast Aman. Such diversified cropping pattern is also due to different soil type. The western and south-western parts of the command area which are near to the STW are mostly composed of sandy soil and this type of soil is good for vegetables. This sandy soil mainly comes from the abandoned sand bars of the nearest Kalidaha River. On the other hand, the eastern part of the command area is mostly composed of Silty clay and that is good for paddy cultivation. The small part of the village has such micro variations. This influences the irrigation, initial investment and also cash flow. The intensity and management of irrigation of the command area is not uniform.
Mostly one irrigation and in some cases two irrigations are needed for vegetables to grow over the cropping period. The cost of irrigation for vegetables is BDT 100-200 per irrigation per plot, whereas it is one-fourth share of the crop for Boro rice.
Under Irrigation
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Figure 5.6: Cropping pattern of a command area in Kurmushi mauza in 2016 5.3.4 Cropping Pattern Analysis of Saitapara Mouza
There is also simple cropping pattern present at Saitapara mauza of the study area. For example, A STW of Bozlu in Saitapara covers about 2.19 hectares of land which consists of 20 plots in the command area. The cropping pattern of the command area is Boro-B.Aman-Mustard in normal flood year. Such a small command area has land elevation variation. Flood water was a little bit higher in the last year (2016) and that is why broadcast Aman paddy was damaged in the lower elevated lands but the crop on the higher elevated land survived. Figure 5.7 shows that four plots do not have direct connection with the water distribution channel of the STW. Actually these plots are lower in elevation than the other plots of the command area and thus do not have channel connection but get irrigation water by seepage and overflow through higher elevated lands.
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Figure 5.7: Cropping pattern of a command area at Saitapara mauza in 2016 5.4 CONCLUSION
This research study concluded that mainly two types of irrigation equipment used to abstract groundwater for the Boro paddy cultivation in the study area in the past up to 2007. They were diesel operated STW (DOS) and electricity operated STW (EOS). But at present (2017), there was no exists of DOS in the study area, only EOS is running. The study revealed that in 1997, DOS was 76% and EOS was 24%, while in 2007 those were 46% and 56% respectively and in 2017 those were 4% and 96% respectively. The last twenty years since 1997 using of DOS has been decreased and using of EOS has been increased 40% respectively. In addition, STWs location and command areas were changed little bit and there was no significant change found in land use pattern over last twenty years since 1997 in the study area. The research findings also showed that there were seven different cropping patterns found in the study area. Main cropping patterns were Boro-T. Aman-Mustard and Boro-B. Aman-Mustard. Diversified cropping pattern was found in the study area due to the different soil type and the different land elevations.
It was observed during field survey of this study that most of the farmers are using Chinese motor, though there are some other motor from different country’s origin. It may be due to fewer prices of Chinese motor and available spare parts in the market. It also may be due to high price of diesel cost and less operation cost of electricity STWs. However these should be studied for further validation. In this perspective, further study is needed to be conducted to investigate 1) why most of the farmers were using Chinese motor, 2) the characteristics of those motors and 3) hydraulic, agricultural and economic performance of STWs. Therefore, further research focuses about evaluation of STW equipment characteristics and performance (hydraulic and agricultural) of EOS in Chapter 6 and financial analysis in Chapter 8.
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