Water allocation policies for the Dong Nai River Basin in Vietnam: an integrated perspective

Recent water sector reforms, increased scarcity and vulnerability of existing water resources, combined with declining public funding available for large-scale infrastructure investment in the sector have led to an increased awareness by the Government of Vietnam for the need to analyze water resource allocation and use in an integrated fashion, at the basin scale, and from an economic efficiency perspective. This paper presents the development, application, and results from an integrated economic-hydrologic river basin model for the Dong Nai River Basin in southern Vietnam that attempts to address these issues. The model framework takes into account the sectoral structure of water users (agriculture, industry, hydropower, households, and the environment), the location of water-using regions, and the institutions for water allocation in the basin. Water benefit functions are developed for the major water uses subject to physical, system control, and policy constraints. Based on this modeling framework, policies that can affect water allocation and use at the basin level, including both basin-specific and general macroeconomic policies, are analyzed.River basin model, water allocation policy, integrated assessment, Vietnam, Dong Nai basin, Water resources Economic aspects,

Transferring and extrapolating estimates of cost-effectiveness for water quality outcomes: Challenges and lessons from the Great Barrier Reef

In recent decades the declining health of the Great Barrier Reef has led to a number of government policies being implemented to reduce pollutant loads from the adjacent agricultural-based catchments. There is increasing use of cost-effectiveness measures to help prioritise between different programs and actions to reduce pollutants, given limited resources and the scale of the issues. However there are a small number of primary studies available, and the consistency of cost-effectiveness measures and their application is limited, particularly given the various uncertainties that underlie the measures. Unlike Europe and the United States of America water policy or benefit transfer approaches, there are no procedural guidance studies that must be followed in the context of the Great Barrier Reef catchments. In this study we review the use of cost effectiveness estimates for pollutant reduction into the Great Barrier Reef in the context of a benefit transfer framework, where estimates of costs from a particular case study are transferred to various scenarios within different catchments. The conclusions suggest a framework be developed for the Great Barrier Reef, which is consistent, transparent, and rigorous

The role of rainfed agriculture in the future of global food production:

This paper examines future prospects for rainfed cereal production, and its importance in the evolving global food system. First, the paper undertakes a critical synthesis of the literature to assess three primary ways to enhance rainfed cereal yields: increasing effective rainfall use through improved water management, particularly water harvesting; increasing crop yields in rainfed areas through agricultural research; and reforming policies and increasing investments in rainfed areas. Second, the IMPACT-WATER integrated water-food modeling framework is applied to assess the current situation and plausible future options of irrigation water supply and food security, primarily on a global scale. This model simulates the relationships among water availability and demand, food supply and demand, international food prices, and trade at regional and global levels. The results show that rainfed agriculture will maintain an important role in the growth of food production in the future, although appropriate investments and policy reforms will be required to enhance the contribution of rainfed agriculture.Agricultural policy., Rainfed farming Developing countries., Cereal crops. Agricultural policy., Rainfed farming Developing countries., Cereal crops., Food security., Water-supply., Food supply., Trade., Crop yields., Water use Management.,

Effekt av klima og jordbruk på hydrologi og vannkvalitet : en studie av små jordbruksdominerte nedbørfelt

Eutrophication and degradation of water quality are global problems and affect many freshwater and coastal systems. Agricultural areas are major contributors of nutrients and soil particles in streams and lakes. The objectives of this study were to discuss the impacts on water quality and quantity of expected land use changes due to a transition to bioeconomy (the green shift) in Norwegian agricultural catchments; to detect trends in climate and hydrology; and to describe and understand catchment processes related to runoff, soil and nutrient losses. The study has been carried out in seven Norwegian small headwater catchments and has included analyses of long-term data series (26 years) as well as collection of new data, in particular high-frequency sensor data on turbidity and water samples for a stable water isotope (18O, 2H) analysis. Moreover, data from a network of Nordic catchments (69 sites in total) have been included in the study. Analysis for the thesis was done using latest statistical and time series analytical methods. Pressures on deterioration of water quality related to bioeconomy activities have been discussed based on data from 69 Nordic catchments. A green shift in Nordic agriculture might imply more intensive land use or clearing of new land. Our study showed that agricultural sites show the highest concentration and fluxes of total nitrogen and phosphorus compared to forestry-impacted and natural catchments. In addition, pressures from climate change (droughts and heavy rainfalls) and their combined effects can pose severe threats to water quality in Nordic regions. The analysis for seven Norwegian catchments revealed changes in meteorological inputs and hydrological responses. The annual mean temperature increased significantly during 26 years of observations in six of the seven studied catchments. This increase in temperature affected evaporation, the hydrological regime, the snow water equivalent, nutrient concentration, and the length of the growing season. In four of seven catchments the snow water equivalent decreased significantly during winter, and only one catchment showed an increase. The change in the snow regime affects the hydrology of the snow-dominated catchments (main runoff events due to snowmelt periods). Hydrological patterns varied between the seven catchments depending on whether they were located at the coast (rain-dominant) or inland (snow-dominant). In the rain-dominated catchments precipitation and discharge showed a strong coherence. Snow-dominated catchments showed a weaker coherence, because precipitation as snow is not immediately available for discharge. Snow precipitation does not translate to discharge until snowmelt occurs. Extreme conditions, as in 2010 (relative low average temperature) and 2018 (drought), seemed to decrease the coherence between runoff and variables such as precipitation, snow water equivalent, and soil water storage capacity in four of the catchments. Climatic and hydrological long-term changes could be best detected at the seasonal scale. Studied variables such as discharge, turbidity, field operations, crop factor, connectivity index, soil water storage capacity, and snow water equivalent showed a strong seasonality. In our study we also considered factors which impact the concentrations and losses of nutrients and sediments. We found that a prolonged growing season coincided with a decrease in nitrogen concentrations in cereal dominated catchments. However, this change in growing season length did not affect the farmers’ sowing time, nor did they harvest earlier, assumedly because soil moisture is in this case the determining factor for soil workability. Nutrient and sediment losses were closely linked to hydrological processes in study catchments. Results from the multivariate regression of two monitored catchments showed that discharge is one of the main drivers for sediment and particulate phosphorus concentration (explained 50% of the variation in turbidity). For nitrogen, an increase in discharge gave a dilution effect. High frequency turbidity sensor data revealed that the concentration-discharge patterns of runoff events were characterised by turbidity peaks before discharge peaks. This indicates a rapid mobilisation of suspended sediments and particulate phosphorus. Channel bed dynamics, including stream bank erosion and remobilisation of in-stream particles contribute to these patterns. A high-water discharge in a first storm event in general reduced the sediment transport in the following event, suggesting depletion of available in-stream/near-stream material. Detecting responses of agricultural management were challenging using sensor-data. In general, detecting responses of agricultural land management on stream water quality and quantity at catchment scale proved to be challenging due to spatial variations in field management, topography, soil, hydrology, and vegetation. Therefore, it is important to continue monitoring programs, especially where long-term datasets exist. Responses of climate, hydrology and land management on water quality were different from catchment to catchment, which is why it is important to apply land management and mitigation measures adapted and tailored to the local conditions.Eutrofiering og forringet vannkvalitet er globale problemer som påvirker mange ferskvanns- og kystsystemer. Jordbruk er en av de sektorene som bidrar mest med næringsstoffer og jordpartikler i bekker, elver og innsjøer. Hensikten med denne studien har vært å diskutere effekter på vannkvalitet og hydrologi som følge av en overgang til bioøkonomi (det grønne skiftet); å oppdage trender innen klima og hydrologi; og å beskrive og forstå nedbørfeltprosesser knyttet til avrenning, tap av jord og næringsstoffer. Studien har blitt utført i syv norske nedbørfelt og inkluderte analyser av lange dataserier (26 år) samt innsamling av nye data, spesielt høyfrekvente sensordata av turbiditet, og vannprøver for en stabil vannisotopanalyse (18O, 2H). Videre er data fra et nettverk av nordiske nedbørfelt (totalt 69 felt) inkludert i studien. Dataene ble analysert med forskjellige statistiske metoder: Mann-Kendall trendanalyse, lineær blandet modell, multivariat regresjon og en såkalt wavelet coherence analyse. Utfordringer for vannkvalitet knyttet til innføring av bioøkonomi har blitt diskutert basert på data fra 69 nordiske nedbørfelt. Et grønt skifte kan innebære mer intensiv arealbruk eller rydding av nytt land for oppdyrking. Dataene viser at jordbruksbekker allerede i dag har de høyeste konsentrasjoner og tilførsler av totalnitrogen og fosfor sammenlignet med bekker i skogbruksområder og naturlige nedbørfelt. I tillegg kommer klimaendringer (tørke og store nedbørsmengder), og den kombinerte effekten kan være en alvorlig trussel mot vannkvaliteten. Den årlige gjennomsnittstemperaturen økte betydelig i løpet av 26 års observasjoner i alle de syv undersøkte nedbørfeltene, bortsett fra ett. Denne temperaturøkningen påvirket fordampning, det hydrologiske regimet, snøvannets ekvivalent, næringsstoffkonsentrasjon og lengden på vekstsesongen. I fire av sju nedbørfelt ble snøvanns-ekvivalenten betydelig redusert om vinteren, og bare ett nedbørfelt hadde en økning. Denne endringen i snøregimet påvirker hydrologien i snødominerte nedbørfelt, dvs. der avrenningsmønster er sterkt preget av snøsmelting. Hydrologiske mønstre varierte mellom de syv nedbørfeltene, avhengig av om det var regn- eller snø-dominert, noe som igjen hang sammen med geografisk plassering (innland eller kyst). I regn-dominerte nedbørfelt var det en tydelig sammenheng mellom nedbør og avrenning. Snø-dominerte nedbørfeltfelt viste ikke en sterk sammenheng, fordi nedbør som snø først gir økt avrenning under snøsmelting. Ekstremår som i 2010 (relativ lav gjennomsnittstemperatur) og 2018 (tørke) så ut til å redusere sammenhengen mellom avrenning og variabler som nedbør, snøvanns-ekvivalent og lagringskapasitet i jord i fire av nedbørfeltene. Klimatiske og hydrologiske langsiktige endringer kan best oppdages på sesongskalaen. Studerte variabler som avrenning, turbiditet, dyrkingspraksis, avlingsfaktor, konnektivitet, lagringskapasitet for jordvann og snøvannekvivalenter hadde en sterk sesongavhengighet. En forlenget vekstsesong samvarierte med reduserte nitrogenkonsentrasjoner i korndominerte nedbørfelt. En endring i vekstsesongens lengde påvirket ikke bøndenes såtid eller høstetid, antagelig fordi jordfuktighet i dette tilfellet er den avgjørende faktoren for når jorda er laglig for bearbeiding. Næringsstoff- og sedimenttap er nært knyttet til hydrologi. Resultatene fra den multivariate regresjonen viste at avrenningen er en av hovedårsakene for sediment- og partikkelbundet fosforkonsentrasjon (forklarte 50% av variasjonen i turbiditet). For nitrogen ga en økning i avrenning en fortynningseffekt. Turbiditet-sensordata viste at turbiditet kulminerer før avrenningen. Dette indikerer en rask mobilisering av suspenderte sedimenter og partikkelbundet fosfor. Dynamikken i bekkene, som erosjon og remobilisering av partikler, samt størrelsen av tidligere avrenningsepisoder spilte også en viktig rolle for transport av sediment. Det er utfordrende å finne sammenhenger mellom jordbruksaktivitet og vannkvalitet og hydrologi i nedbørfelt på grunn av romlige variasjoner i topografi, jord, hydrologi, driftspraksis og vegetasjon. Derfor er det viktig å fortsette med overvåkningsprogrammer, spesielt der det finnes lange dataserier. Responsene på vannkvalitet av klima, hydrologi og jordbruk var forskjellige fra nedbørfelt til nedbørfelt, og derfor er det viktig at arealforvaltning og tiltak er tilpasset lokale forhold

WHERE TO AIM: EVALUATING MICONIA MANAGEMENT WITH HERBICIDE BALLISTIC TECHNOLOGY IN MAUI

M.S

Swat Model Simulation of Bioenergy Crop Impacts in a Tile-Drained Watershed

Tile drains are an important component of agricultural production in the Midwest, and their inclusion in modeling studies is important in watersheds where they are a principal hydrologic pathway. The new tile drainage simulation method in the Soil Water Assessment Tool (SWAT) was parameterized and tile flow results were compared with reviewed literature. Streamflow, sediment, and nutrient outputs were compared to measured values and simulated crop yields were examined with respect to average county yields. Plant growth stressors were examined to account for differences between simulated and published yields. The bioenergy crop switchgrass (Panicum virgatum) was applied over the watershed in land use scenarios developed from a review of published modeling studies and scenario planning literature. Differences in water quality and quantity arising from these land use changes, simulated by SWAT, were quantified