دانلود رایگان مقاله ارزش ویژه در قسمت سوم کاریز از سیستم آبیاری حوضه سند (IBIS)

abstract

This paper examines the fairness in distribution of water in a tertiary canal within the Indus Basin Irrigation System. Two methodologies are proposed: canal rating equations, and outlet discharge equations. The methodology is applied to a tertiary canal located in the Punjab, Province of Pakistan. Fairness/equity is expressed quantitatively using the Gini index. There is a difference in the estimated discharge depending on the methodology employed, however as we move along the canal the water allowance does not vary significantly with the distance along the canal. Hence for this particular canal the head-middle-tail inequity often reported and generalized in the literature is not observed. The advantage of a quantitative measure of inequity such as the Gini is exemplified by comparing the Gini with that at the secondary canal and also against itself if the tertiary canal could be operated “as designed”. We introduce two new concepts: systematic and operational inequity. Provided the costs of data acquisition can be reduced this technology has the potential to be scaled up and included in future development investments in large scale irrigation systems. Further work exploring the impact of information on stakeholders needs to be undertaken.

4. Conclusion and recommendations In this paper we have demonstrated the application of summary statistical measures of equity to the tertiary canal/outlet level. The volume (per unit area) is estimated using two techniques. There is a difference in the estimated discharge depending on the methodology employed. However irrespective of the methodology used to estimate volume per unit area, neither indicate a decrease in volume per unit area with distance along the canal. Hence at least for the case of the tertiary canal 5R during Kharif 2015 we do not observe the head-middle-tail inequity often cited and generalized in the literature. We have also shown that although the depth of flow at the tail end of a canal is widely used in the Indus Basin Irrigation System as a proxy indicator, this is in fact a poor indicator of equity. We reaffirm that measuring flows within a canal where dedicated flow measurement structures do not exist and one has to resort to rating equations and/or measuring discharge through outlets still poses a challenge. However it is still possible to obtain reasonable estimates and thereby determine the inequity in the system. The advantage of using a quantitative measure of inequity such as the Gini as opposed to the qualitative description hitherto more common is thatit allows alternative comparisons to be made. We compare the inequity in the tertiary canal with thatin the upper tier secondary canal and also with inequity had the system been operated “to design”. Thereby we have introduced new concepts of systematic and operational inequity. Up scaling the installation of electronic equipment at the density of approximately 2 per 1000 m, (instrument density in this work), throughout the Indus Basin Irrigation System would be prohibitively expensive. Exploring more cost-effective solutions and the impact of compromising on spatial, and/or temporal resolution of data acquisition is the subject of on-going work. Estimations of both canalflows and outlet discharges needs to be improved further if one is to convince practitioners and policy makers of the value of such research. This technology could allow for disseminating management information namely; discharge, volumes and summary statistics on equity disaggregated by individual outlet level and on a weekly basis to coincide with the warabandi weeks. Individual farmers could identify with this information as each farmer knows which outlet s/he receives water. The impact that such information could have on the perceptions of the farmer on how water is being managed and also the interactions with the irrigation agencies could also be the subject of further work.