External Virtual Water Contributes Greatly to Continual Development in Urumqi
Issue:
Volume 7, Issue 4, December 2019
Pages:
56-61
Received:
10 September 2019
Accepted:
2 December 2019
Published:
7 December 2019
Abstract: Previous studies indicated that the population size would arrive at its “upper limits” under the intense water scarcity in Urumqi; yet the “upper limits” had been repeatedly exceeded. Two latest research paper put forward a new term “generalized water”, and estimated it under the framework of a noncompetitive input-output model. It was proved that generalized water made a main contribution to alleviate acute water scarcity in the past 40 years in the arid city, and answered the question why an urban population continues to grow under intensifying water scarcity. Another question is whether and how generalized water contributes to the continual development in the future in this city. This paper applied coefficients deduced from the noncompetitive input-output model, and set up a multi-objective linear programming model to investigate the question. Simulation results indicated that the upper limit of gross domestic products of Urumqi would be at most 1.3 times that in 2012; however, this “upper limit” was far more exceeded in 2018, about 1.7 times that in 2012. This phenomenon indicates that generalized water also made a main contribution to continual development, and this contribution mainly comes from external virtual water embodied in commodities. This contribution from generalized water results from the characteristic of dissipative structure in an urban economy, and it is suggested that polices should be designed to make the most use of generalized water.
Abstract: Previous studies indicated that the population size would arrive at its “upper limits” under the intense water scarcity in Urumqi; yet the “upper limits” had been repeatedly exceeded. Two latest research paper put forward a new term “generalized water”, and estimated it under the framework of a noncompetitive input-output model. It was proved that ...
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Development of a Water Allocation Model for Equitable Water Distribution at Doho Rice Irrigation Scheme, Uganda
Erion Bwambale,
Patrick Gathogo Home,
James Messo Raude,
Joshua Wanyama
Issue:
Volume 7, Issue 4, December 2019
Pages:
62-69
Received:
6 October 2019
Accepted:
2 January 2020
Published:
16 January 2020
Abstract: The shortage of irrigation water at the tail reaches of Doho Rice Irrigation Scheme especially in the dry season has resulted in decreased rice production. At Doho Rice Irrigation Scheme, water distribution follows a predetermined rotation system where allocated supplies are unknown and the farmer decides how much water they divert to their plot. This has resulted in water inequalities between the tail end and head end blocks of the scheme. The main objective of the study was to develop a water allocation model for equitable distribution of irrigation water taking into account crop growth stages. This study developed an equitable water allocation model by ensuring that the crop water requirements per block are matched with the available supply in the main canal. A water delivery scheduling model was developed to help deliver the decadal irrigation water requirements by grouping different blocks together. The water allocation model gives required irrigation supplies and recommended supplies depending on the crop growth stage and acreage per block. The results from the water delivery scheduling model suggest a 2 days of irrigation per week for the land preparation, development and late seasons and 3 days of irrigation per decade during the high consumptive stages of initial and midseason stages of rice development.
Abstract: The shortage of irrigation water at the tail reaches of Doho Rice Irrigation Scheme especially in the dry season has resulted in decreased rice production. At Doho Rice Irrigation Scheme, water distribution follows a predetermined rotation system where allocated supplies are unknown and the farmer decides how much water they divert to their plot. T...
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