Browsing by Author "Chengot, Rishma"

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    ItemOpen Access
    An enhanced version of the D-Risk decision support webtool for multi-scale management of water abstraction and drought risks in irrigated agriculture
    (Elsevier, 2022-11-26) Chengot, Rishma; Knox, Jerry W.; Coxon, Gemma; Cojocaru, George; Holman, Ian P.
    Due to it having the lowest priority for water allocation during drought events and the consequent agronomic and economic impacts of abstraction restrictions, UK irrigated agriculture has been identified as a key business sector ‘at risk’. An enhanced version of the D-Risk webtool has been developed to help agricultural stakeholders and catchment water managers to evaluate the joint multi-scale risks of abstraction restrictions (voluntary and mandatory) and having insufficient irrigation volumes during drought events. The webtool uses annual maximum potential soil moisture deficit as the agroclimate index to calculate monthly and annual volumetric irrigation demand for the selected crop mix, soil available water capacity and location. Simulated river flows are used to identify days not under abstraction restrictions. Annual probability distributions of irrigation deficit and licence utilisation (headroom) are derived from a monthly time-step water balance model that calculates whether the farm irrigation demand in each month can be met, taking account of river flow-based abstraction restrictions, daily and annual volumetric licensed abstraction limits, the licenced abstraction period(s) and any on-farm reservoir storage. The enhanced D-Risk tool provides a more holistic understanding of drought risk on irrigated agriculture from individual farm to catchment scales and supports improved collaborative decision-making regarding future water sharing, water trading and on-farm reservoir investment to reduce business vulnerability to drought and regulatory change.
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    ItemOpen Access
    Evaluating the feasibility of water sharing as a drought risk management tool for irrigated agriculture
    (MDPI, 2021-01-30) Chengot, Rishma; Knox, Jerry W.; Holman, Ian P.
    Droughts can exert significant pressure on regional water resources resulting in abstraction constraints for irrigated agriculture with consequences for productivity and revenue. While water trading can support more efficient water allocation, high transactional costs and delays in approvals often restrict its wider uptake among users. Collaborative water sharing is an alternative approach to formal water trading that has received much less regulatory and industry attention. This study assessed how the potential benefits of water sharing to reduce water resources risks in agriculture are affected by both drought severity and the spatial scale of water-sharing agreements. The research focused on an intensively farmed lowland catchment in Eastern England, a known hot-spot for irrigation intensity and recurrent abstraction pressures. The benefits of water sharing were modelled at four spatial scales: (i) individual licence (with no water sharing), (ii) tributary water sharing among small farmer groups (iii) sub-catchment and (iv) catchment scale. The benefits of water sharing were evaluated based on the modelled reductions in the probability of an irrigation deficit occurring (reducing drought risks) and reduced licensed ‘headroom’ (spare capacity redeployed for more equitable allocation). The potential benefits of water sharing were found to increase with scale, but its impact was limited at high levels of drought severity due to regulatory drought management controls. The broader implications for water sharing to mitigate drought impacts, the barriers to wider uptake and the environmental consequences are discussed
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    ItemOpen Access
    Evaluating the impacts of agricultural development and climate change on the water-energy nexus in Santa Elena (Ecuador)
    (Elsevier, 2023-12-22) Chengot, Rishma; Zylberman, Raphael; Momblanch, Andrea; Salazar, Oswaldo Viteri; Hess, Tim; Knox, Jerry W.; Rey, Dolores
    A combination of a changing global climate coupled with rapid socio-economic development is putting unprecedented pressure on water, energy, and food resources. Addressing these issues within a nexus approach can help to identify appropriate management practices and strategic policies to ensure natural resources are used more sustainably thus avoiding exacerbating issues of water scarcity and food insecurity. In this study, we used an integrated water resource planning and irrigation model (WEAP) to assess emerging water-energy nexus issues on the Santa Elena peninsula in Ecuador. Simulated water demands showed that current water resources availability is insufficient to meet full irrigation requirements, especially during the dry season. Annual average energy demand for water conveyance in the SEP was significantly higher than for irrigation with 94.5 GWh and 13.5 GWh being used, respectively. Future challenges associated with changes in agricultural irrigation and urban demands within the SEP were evaluated using scenario analysis. This included considering various scenarios such as agricultural expansion, climate change, population growth, and a shift to export-oriented agriculture. The study underscores the significance of nexus thinking in guiding policy and decision-making in Santa Elena, although the limited data prevents its use in an operational framework. The benefits of adopting an integrated modelling approach to analyse water and energy nexus trade-offs are also discussed.