A water availability Assessment for improvement of community managed irrigation schemes : the case of Mkwasine diversion system in the South Eastern Lowveld of Zimbabwe | |
| Author | Mandirega, Siyakia |
| Call Number | AIT Thesis no.AWM-17-01 |
| Subject(s) | Irrigation--Zimbabwe, Southeastern--Management Irrigation water--Management |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Water Engineering and Management with specialization in Agricultural Water Management for Enhanced Land and Water Productivity offered by the Asian Institute of Technology, Thailand and IRE Delft, The Netherlands |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. AWM-17-01 |
| Abstract | This thesis study was aimed at assessing the availability and adequacy of irrigation water on the Mkwasine diversion system and identify appropriate interventions to enhance the water availability for both community and sugarcane farmers. To meet this objective, existing models were applied to evaluate the status and water use basing on surface flow measurements of flows released from the Manjirenji dam, rainfall data and estimation of crop water requirements. Specifically the IWMI water accounting was applied to analyze the water availability for the five consecutive agricultural seasons (2010/11 to 2014/15). The CROPWAT8.0was run to estimate irrigation water requirements of sugarcane and grain crops (maize wheat and sugar beans) being grown on the Mkwasine diversion system. The estimated water supply and demand were then used to assess the adequacy of water delivery and evaluate if there were water shortage or surplus with regard to irrigation requirements. Proposed interventions strategies were identified based on the water accounting indicators, mainly the process fraction depleted to evaluate the potential of water saving on the service system. Availability of irrigation water on the Mkwasine diversion system is variable seasonally or annually. Mean available irrigation water was found to be 177 Mm^3 with a standard deviation of 18 Mm^3 and coefficient of variation of 10%. It was established from the water accounting analysis that all the available water into the Mkwasine system are being depleted. On average total water supplies over the covered agricultural seasons were only meeting 80% of the gross irrigation demand. The system experiences water shortage as was revealed by RWS values less than 1.5 for all the agricultural seasons covered by the study. Water supply is not adequate from around February through August and October when farmers only rely on canal water supply from Manjirenji dam. The installed irrigation water conveyance infrastructure is also limitation during peak demand periods. It was estimated that if the current installed irrigation offtakes are utilized to their capacity water demand will rise by 13 % and this may exacerbate/ aggravate the prevalence of water shortage and spark conflicts among farmer groups. However when water saving practices and application technologies are implemented on sugarcane farms water can be released to accommodate communal irrigation expansion to improve food security. |
| Year | 2017 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. AWM-17-01 |
| Type | Thesis |
| School | School of Engineering and Technology |
| Department | Department of Civil and Infrastucture Engineering (DCIE) |
| Academic Program/FoS | Agricultural Water Management (AWM) |
| Chairperson(s) | Sanyogita Andriyas |
| Examination Committee(s) | Poolad Karimi;Damien Jourdain;Sangam Shrestha |
| Scholarship Donor(s) | Joint Japan /World Bank Graduate Program (JJ/WBGSP)/UNESCO-IHE;AIT Fellowship |
| Degree | Thesis (M. Eng.) - Asian Institute of Technology, 2017 |