http://drw.jfn.ac.lk/handle/123456789/50 2026-04-20T07:46:29Z http://drw.jfn.ac.lk/handle/123456789/278 Impacts on Irrigation Infrastructure Development Projects on Agriculture sector: A Case study in Iranamadu Irrigation Scheme of Sri Lanka. Suthakaran, N.; Paraneetharan, S. Agriculture sector development to ensure food security for escalating population inevitably requires Irrigation infrastructure development. Recognizing this fact, both Government and Donors make significant investments in irrigaGon development in developing counties.In the recent times, the funding agencies show lack of motivation in investing on irrigation development projects due to high likelihoods of uncertainty on the return of investments. To convince them about the positive impacts and to attract them, an impacts needs to be assessed on irrigation development and management. As such, this case study was undertaken in recently developed Iranamadu Irrigation Scheme, which is the largest reservoir in the Northern Province, to irrigate 8698 ha of paddy and other field crops by both gravity and lift irrigation facilities benefitting 7000 farmers. With the intervention of Asian Development Bank (ADB) and the International Fund for Agriculture Development (IFAD), investing 42 Mn USD, scheme has been rehabilitated and augmented recently. After the project completion in year 2018, significant improvement has been observed in agricultural development. This study is based on scientific parameter; cropping intensity, water duty and productivity which are the main indicators for the lrrigafion investment. A scientific methodology is developed to compare parameters before and after project implementation in both Maha and Yola seasons, in order to examine the impact on the irrigation development programme. The results of the analysis revealed that positive impact is there immediately after project completion; especially cropping intensity has increased drastically by 0.40 (from 1.30 to 1.70), reaching 1.7 which is more than the national average for the major irrigation schemes, though irrigation impact is long term. The significant incremental benefit agriculture investment has a positive economical impact thus encourage agencies to invest more on irrigation development projects. 2019-01-01T00:00:00Z http://drw.jfn.ac.lk/handle/123456789/236 Physical background of the Kanagarayan river basin Subajini.T 2004-01-01T00:00:00Z http://drw.jfn.ac.lk/handle/123456789/141 Conjunctive use of surface and groundwater to improve food productivity in Vavuniya district in the dry zone area Sivakumar, S.S. This research presents alternate policy decisions based on technical strategies to operate minor and medium irrigation schemes with integrated conjunctive use of surface and groundwater to improve groundwater systems in Vavuniya area for the economic pumping for agricultural and domestic water use, by optimizing the use of groundwater and surface water. Forty one domestic dug wells were identified as observation wells among the available domestic/agro wells within the study area of 185.23 km2 ,to represent the aquifer in Vavuniya. This study area was divided into forty one Thiessen polygons. A complete water balance study for each polygon for each season was carried out. Water levels were predicted for changes in operational policy of minor and medium irrigation schemes by forgoing certain percentage of cultivation, boundary treatment to reduce the transmissibility in steps, and combination of both. The economic feasibility was analysed by taking the energy saved in pumping of raised groundwater as a benefit and boundary treatment cost and income loss due to change in operational policy of minor and medium irrigation schemes by forgoing certain percentage of cultivation as cost. The present worth of benefit and cost for various interest rate and project life period were calculated and compared. Change in operational policy of minor and medium irrigation schemes by forgoing one third of the cultivation under them or keeping one fourth of the storage of minor and medium irrigation schemes at any time together with 40% - 50% reduction in boundary permeability will recover an average of 60% to 70% of the loss of water table in any consecutive season in almost 95% of the area under consideration. 2013-01-01T00:00:00Z http://drw.jfn.ac.lk/handle/123456789/119 Investigate the post war improvements of hydraulicinfrastructure in irrigation systems of Kanagarayan aru river basin using hydrological model Janithra, S.; Pratheeba, J.; Athapattu, B.C.; Sampath, D.S.; Sivakumar, S.S. Jaffna, Kilinochchi, Mullaitivu, Vavuniya and Mannar districts are under the Northern Province. Most of the northern region got affected due to the civil war around 30 years. Due to this war water resources development were damaged severely. The major, medium and minor irrigation systems were dilapidated conditions. After the resettlement stack holders are engaged with agriculture activities and several investments were done for the irrigation infrastructure. However still stack holders suffering with cultivation issues. Most of the area of the Northern Province has been used for paddy cultivation. During the dry seasons most of the irrigation schemes in this area became dry. Hence the command area of those irrigation schemes cannot be irrigated successfully for two seasons. As a consequence cultivated crops fail and farmers are affected heavily. Hydrological Modeling is a commonly used tool by water resources planners to simulate the hydrological response in a basin due to the precipitation for the purpose of management of basin water. With the increasing demand for limited water resources in every basin, careful management of water resources becomes more important. The Kanagarayan Aru River Basin in Srilanka supplies water to number of new and ancient irrigation systems and the management of water resources in the Kanagarayan Aru River Basin. total catchment area of this River Basin is 906Sq.Km. Important for optimum utilization of water for these irrigation systems in the project continuous rainfallrunoff modeling in pat of the Iranamadu Tank, Chemamadu Tank and Kanagarayan Kulam Tank. Storage Irrigation systems using the hydrological Engineering centre – Hydrologic Modeling System (HEC-HMS) VERSION 3.0.1 to estimate the runoff in the Kanagarayan Aru River 2018-01-01T00:00:00Z