Improve Water Security Research Articles

Urban Streamflow Impact Assessment (USIA): a novel approach for protecting urbanising waterways and providing the justification for integrated water management

ABSTRACT As urban populations expand globally, the associated increase in urban land cover directly impacts the social and environmental amenity of natural assets, including waterways. The primary driver of urban waterway degradation changes in land uses which results in altered hydrology – from stormwater runoff, and where present, wastewater treatment plant discharge. Whilst the impacts of pollutants are relatively well regulated via public policy, a gap remains for the management of flow regime modification. The Urban Streamflow Impact Assessment (USIA) was developed to fill this management and planning knowledge gap. The approach begins with the identification of waterway values (social, ecological and geomorphic) then explicitly links these values to streamflow characteristics using hydraulic and hydrologic metrics. USIA was applied to a case study in Western Sydney and demonstrated the loss of values associated with ‘business-as-usual’ approaches to stormwater and wastewater management. Conventional stormwater management approaches do not remove enough excess flow to meet reasonable outcomes for the waterway. This excess runoff is increasingly seen as a resource and opportunity for improving water security and liveability. USIA is consistent with regulatory frameworks and can be applied across developing and established urban catchments to provide explicit input to planning controls. The approach is appropriate at multiple scales, informing urban planning from a broad strategic level through to detailed design. By linking social and ecological values with geomorphic and flow requirements, the approach enables an understanding of which management approaches could allow desirable waterway outcomes to be met.

Disruptive Technologies for Improving Water Security in Large River Basins

Large river basins present significant challenges for water resource planning and management. They typically traverse a wide range of hydroclimatic regimes, are characterized by complex and variable hydrology, and span multiple jurisdictions with diverse water demands and values. They are often data-poor and in many developing economies are characterized by weak water governance. Rapid global change is seeing significant changes to the pressures on the water resources of large basins, exacerbating the challenge of sustainable water management. Diverse technologies have long supported water resource planning and development, from data collection, analytics, simulation, to decision-making, and real-time operations. In the last two decades however, a rapid increase in the range, capability, and accessibility of new technologies, coupled with large reductions in cost, mean there are increasing opportunities for emerging technologies to significantly “disrupt” traditional approaches to water resources management. In this paper, we consider the application of ‘disruptive technologies’ in water resources management in large river basins, through a lens of improving water security. We discuss the role of different actors and institutions for water management considering a range of emerging disruptive technologies. We consider the risks and benefits associated with the use of these technologies and discuss the barriers to their widespread adoption. We obverse a positive trend away from the reliance solely on centralized government institutions and traditional modeling for the collection and analysis of data, towards a more open and dynamic ‘data and knowledge ecosystem’ that draws upon data services at different levels (global to local) to support water planning and operations. We expect that technological advances and cost reductions will accelerate, fueling increased incremental adoption of new technologies in water resources planning and management. Large-basin analytics could become virtually free for users with global, regional, and national development agencies absorbing the costs of development and any subscription services for end users (e.g., irrigators) to help improve water management at user level and improve economic productivity. Collectively, these changes can help to ‘democratize’ water management through improved access to data and information. However, disruptive technologies can also be deployed in top-down or centralized processes, and so their use is sometimes contested or misunderstood. Increased attention therefore needs to be given to ensuring equity in technology access, and to strengthening the governance context for technology deployment. Widespread adoption of disruptive technologies will require adjustments to how water professionals are trained, increased adaptiveness in water resources planning and operations, and careful consideration of privacy and cybersecurity issues.

Deriving optimal operational policies for off-stream man-made reservoir considering conjunctive use of surface- and groundwater at the Bar dam reservoir (Iran)

Study regionThe off-stream artificial Bar lake, built in 2015 to store the flood flows of the Bar river for domestic and industrial needs and with the objective to intentionally recharge the aquifer, is situated in the Razavi Khorasan province (Iran). Study focusWe present a methodology, based on the combination of a MODFLOW groundwater flow model for estimating seepage rates, and an optimization model, for the management and operation of an artificial reservoir considering surface/groundwater interactions for satisfying 12 Mm3/year of water demand. We simulated the reliable amount of water that can be supplied from the reservoir, considering reservoir seepage, maximizing water supply yields subject to the water supply reliability requirements, and the additional intentional volume of groundwater recharge. New hydrological insights for the regionOur results demonstrate the reliability of conjunctive use of surface-and ground-water in water scarce areas by exploiting reservoir infrastructures with relevant leakage losses, also for creating additional aquifer storage. In such systems, man-induced changes of lake stages can significantly affect the volume of water that seeps through the lakebed. The aquifer, under managed aquifer recharge operations, may then provide the resource not satisfied by the reservoir release, fulfilling 100 % reliability of water supply. The conjunctive use of surface- and ground-water, by improving water security, may open new sustainability views for leaking reservoirs, even if they were not initially designed for increasing aquifer recharge, in many areas worldwide.

Using System Dynamic Modeling for Improving Water Security in the Coastal Area: A Literature Review

BACKGROUND: Water is one of the basic materials of human existence. In respect this, many countries have been focused on water security agenda as one of the national strategic security. One of water security domains is coastal water security. Water security, due to the myriad of factors influencing water quantity and quality in coastal area, can be considered as a complex system. Due to the complexity and dynamic characteristic, system dynamic model (SDM) is needed to implement in coastal area to integrate all subsystem.
 AIM: This study aims to analyse the subsystems relating to coastal water security. The subsystem determination used to develop future policy-making relating to coastal water security.
 METHODS: For this purpose, a systematic literature review was conducted and a set of 12 papers was selected from 2009 – 2019.
 RESULTS: The papers’ analysis shows the applicability of SDM to solve complex problems. Water scarcity has been identified as a major problem in the coastal area, identified in eight papers. Three papers are related to water quality and only one paper relating to both. There are four major subsystems relating to coastal water security: environment, economic, social, and politic. Information about the aquaculture activities, the mechanism of coastal water pollution and water relating human health risk is still limited.
 CONCLUSION: We recommend use of SDM in the coastal water security to be extended to aquaculture, coastal water pollution and human health risk aspect in order to promote a holistic understanding of the complex issues and to develop more effective policies.

Prevalence of antibiotic resistance and virulence genes in the biofilms from an aquifer recharged with stormwater

An improved understanding of the diversity and composition of microbial communities carrying antibiotic resistance genes (ARGs) and virulence genes (VGs) in aquifers recharged with stormwater is essential to comprehend potential human health risks from water reuse. A high-throughput functional gene array was used to study the prevalence of ARGs and VGs in aquifer biofilms (n = 27) taken from three boreholes over three months. Bacterial genera annotated as opportunistic pathogens such as Aeromonas, Burkholderia, Pseudomonas, Shewanella, and Vibrio were ubiquitous and abundant in all biofilms. Bacteria from clinically relevant genera, Campylobacter, Enterobacter, Klebsiella, Mycobacterium, Mycoplasma, and Salmonella were detected in biofilms. The mean travel time of stormwater from the injection well to P1 and P3 boreholes was 260 and 360 days respectively. The presence of ARGs and VGs in the biofilms from these boreholes suggest a high spatial movement of ARGs and VGs in the aquifer. The ARGs with the highest abundance were small multidrug resistance efflux pumps (SMR) and multidrug efflux (Mex) followed by β-lactamase C genes. β- lactamase C encoding genes were primarily detected in Enterobacteriaceae, Pseudomonadaceae, Bacillaceae, and Rhodobacteraceae families. The VGs encoding siderophores, including aerobactin (iro and iuc genes), followed by pilin, hemolysin, and type III secretion were ubiquitous. Canonical correspondence analysis suggested that Total Organic Carbon (TOC), Dissolved Organic Carbon (DOC), turbidity, and Fe concentration has a significant impact on the microbial community structure of bacteria carrying ARGs and VGs. Post abstraction treatment of groundwater may be prudent to improve water security and reduce potential health risks.

A Systems Approach to Municipal Water Portfolio Security: A Case Study of the Phoenix Metropolitan Area

We present a rigorous quantitative, systems-based model to measure a municipality’s water portfolio security using four objectives: Sustainability, Resilience, Vulnerability, and Cost (SRVC). Water engineers and planners can operationalize this simple model using readily available data to capture dimensions of water security that go far beyond typical reliability and cost analysis. We implement this model for the Phoenix Metropolitan Area under several scenarios to assess multi-objective water security outcomes at the municipal-level and metropolitan area-level to water shocks and drought. We find the benefits of adaptive water security policies are dependent on a municipality’s predominant water source, calling for a variegated approach to water security planning across a tightly interrelated metropolitan area. Additionally, we find little correlation between sustainability, resilience, and vulnerability versus cost. Therefore, municipalities can enhance water security along cost-neutral, adaptive policy pathways. Residential water conservation and upstream flow augmentation are cost-effective policies to improve water security that also improve sustainability, resilience, and vulnerability and are adequate adaptations to a short-term Colorado River shortage. The Phoenix Metropolitan Area’s resilience to drought is higher than that of any of its constituent municipalities, underscoring the benefits of coordinated water planning at the metropolitan area-level.

The hydrosocial cycle in rapidly urbanizing watersheds

Water is the essential resource of the 21st century where innovative water management strategies are needed to improve water security. This paper examines three case studies that exemplify the global water crisis, situated in rapidly urbanizing watersheds: Nairobi River Basin, Kenya; Citarum River Basin, Indonesia; and Addis Ababa River Basin, Ethiopia. Each of these watersheds are implementing large-scale water management strategies inclusive of local communities and regional governments to address water quality and waste management issues. The hydrosocial cycle (Linton, 2010) provides a framework to investigate the social, technical and physical aspects of water flows. Using the hydrosocial cycle as an organizing framework, these watersheds are examined to highlight how water security underpins water justice. The issues of gender and inequity are often overlooked in larger policy, development, and infrastructure discussions where technical requirements, restoration management, and engineering solutions obscure power inequities. Projects are compared to assess the implementation of the hydrosocial cycle through a discussion of social power and structure, technology and infrastructure, and the materiality of water in each location. This comparison reveals a dependence on large-scale technical projects with limited community engagement, and a need for science-based river restoration management. Recommendations are provided to improve and address holistic water management.

Measuring water security: A vital step for climate change adaptation

Climate change and water are intricately linked. Water is the primary medium through which the impacts of climate change will be felt. Securing the water sector and enhancing water security is, therefore, imperative for any adaptive response to climate change. A precursor in improving water security is to first establish a mechanism to measure it. Only then can incremental and progressive actions be evaluated. This study has developed such a mechanism in the form of a water security assessment framework using an indictor-based methodology. The framework is developed for city-scale analysis because analyses at this scale is more useful in operationalizing water security enhancement. The framework has a three-layered structure comprising five dimensions (broad elements of water security), twelve indicators (areas of interest within the dimensions), and a set of potential variables that can be used to quantify the indicators. The framework has been developed to foster practical interventions for water security enhancement and not as a comparative tool for benchmarking. Hence, while the dimensions and indicators of the framework are fixed, the choice of variables is up to the city depending upon its context. This aspect of the framework, therefore, is meant to help cities introspect internally and move up the water security ladder. The framework culminates into a Water Security Index (WSI), measured on a scale from one to five. The scale is linear and hierarchical in its grade value. The framework was successfully used to assess the water security situation of Bangkok. The study also makes a case for scaling up this intervention for other major cities in Thailand, which can then help implement some of Thailand's key climate change adaptation initiatives such as the Nationally Determined Contributions and the National Climate Change Master Plan.

A review of remote sensing applications for water security: Quantity, quality, and extremes

Water resources are critical to the sustainability of life on Earth. With a growing population and climate change, it is imperative to assess the security of these resources. Over the past five decades, satellite remote sensing has become indispensable in understanding the Earth and atmospheric processes. Satellite sensors have the capability of providing data at global scales, which is economical compared to the ground or airborne sensor acquisitions. The science community made significant advances over recent years with the help of satellite remote sensing. In view of these efforts, the current review aims to present a comprehensive review of the role of remote sensing in assessing water security. This review highlights the role of remote sensing applications to assess water quality, quantity, and hydroclimatic extreme events that play an important role in improving water security. Four water quality parameters, namely, chlorophyll-a, turbidity and Total Suspended Solids (TSS), Secchi Disk Depth (SDD), and Colored Dissolved Organic Matter (CDOM), are considered. Under water quantity assessment, we review three aspects, streamflow estimation, terrestrial water storage, and reservoir operations. Remote sensing applications in quantifying floods and droughts extremes are reviewed in this work. We present how satellite sensor information acquired from different spectral bands, including optical, thermal, and microwave ranges, along with gravity field measurements, have contributed towards the applications in the above areas. We also assess the role of physical models, empirical models, and data assimilation strategies, among others, in the above areas. Finally, possible future research pathways needed to address the issues faced by the science community are discussed. This work is the second of the two-part review series, wherein the first part deals with the applications of satellite remote sensing for agriculture management.

Water Security Assessment of Groundwater Quality in an Anthropized Rural Area from the Atlantic Forest Biome in Brazil

The exploitation of natural resources has grown mainly due to the high rate of population growth that changed over time around the planet. Water is one of the most needed resources essential for survival. Despite all the efforts made to improve water security, an environmental impact related to anthropogenic influence remains of great concern, which is the alteration of surface and groundwater quality. In many regions around the world, there is limited or no access to rural and urban water supply while there is a need to improve sanitation facilities. This work evaluated the spatial distribution of groundwater and surface water quality as well as their changes in wet and dry seasons of the tropical climate in the Atlantic Forest Biome. The study area is under anthropogenic influence, which is in the municipality of Igarassú, Pernambuco State, Brazil. The analysis of the raw water was based on Standard Methods for Examination of Water and Wastewater, as referenced in the Brazilian Ministry of Health Consolidation Ordinance that sets standards for drinking water. The temporal analyses indicated a variation on water quality from the wet to the dry seasons, whereas the spatial results revealed deviations from the Brazilian’s Water Supply Standards for some physicochemical parameters. There was an increase in the values of some parameters during the wet season in some hydrological compartments. The anthropized rural area from the Atlantic Forest Biome is affecting the water quality. It is, therefore, necessary to develop environmental policies and put them into practice by implementing engineering projects that guarantee proper treatment for raw water in order to bring the water quality back to a good status in this region.

Implications of the New Operational Rules for Cantareira Water System: Re-Reading the 2014-2016 Water Crisis

During the 2014-2016 water shortage crisis, the Metropolitan Area of Sao Paulo (MASP) water supply system extracted pumping volume from the Cantareira System. Before the crisis, between 1984 and 2013, the reservoir’s average water extraction flow was 29.6 m3·s-1. During the period of pumping volume usage, the average extraction flow was 16.2 m3·s-1. Following the crisis, two new mitigation policies were implemented: a water extraction Resolution (in 2017) and a Resolution for water reallocation from another basin (in 2018). This study provides a novel investigation of the Cantareira System water crisis by assessing the mitigation policies impacts on storage level dynamics. The system storage level was evaluated using the reservoir simulation module of PDM-Cemaden hydrological model, assuming that the new policies had already been implemented prior to the crisis. A control simulation was run with observed in- and out-flow and operationally-practiced extraction flow. The storage level dynamics impacts were evaluated under 4 water mitigation policies scenarios varying the policies implementation starting date, the extraction flow range and including the water reallocation variable. Results showed that pumping volume would only need extraction during a short period (Scenarios I, III and IV), and considering the water reallocation, pumping volume extraction would not have been necessary (Scenario II). Although the pumping volume would still have been extracted during a short period, water shortage impact would have been lessened, had the policies been already implemented before the crisis. The water mitigation policies implementation supports the reservoirs storage management but does not guarantee that MASP water demand is fully met. Therefore, in order to effectively improve water security, further policies and practices to reduce water demand and enhance supply should be considered.

Achieving water security in Nepal through unravelling the water-energy-agriculture nexus

ABSTRACT This article investigates water security in Nepal from the perspective of the water-energy-agriculture (food) nexus, focusing on pathways to water security that originate in actions and policies related to other sectors. It identifies promoting development of Nepal’s hydropower potential to provide energy for pumping as way to improve water security in agriculture. Renewable groundwater reserves of 1.4 billion cubic meters (BCM), from an estimated available balance of 6.9 BCM, could be pumped to irrigate 613,000 ha of rainfed agricultural land in the Terai plains, with a potential direct economic gain of USD 1.1 billion annually and associated benefits including promotion of energy-based industry, food security and local employment. Governance also plays an important role in addressing water security. We conclude that a nexus-based approach is required for effective water management and governance.

Gendered Water Insecurity: A Structural Equation Approach for Female Headed Households in South Africa

Intricacies between women and water are central to achieving the 2030 Sustainable Development Goals (SDGs). Gender equality and women empowerment is a key driver in ending hunger and poverty as well as improve water security the study sought to identify and provide pathways through which female-headed households were water insecure in South Africa. Secondary data collected during the 2016 General Household Survey (GHS) was utilised, with a sample of 5928 female-headed households. Principal Component Analysis and Structural Equation Modelling were used to analyse the data. The results show dynamic relationships between water characteristics and water treatment. There were also associations between water access and wealth status of the female-headed households. Association was also found between water access and water treatment as well as between wealth status and water treatment. The study concludes that there are dynamic relationships in water insecurity (exposure, sensitivity and adaptive capacity) for female-headed households in South Africa. The study recommends that a multi-prong approach is required in tackling exposures, sensitivities and adaptive capacities to water insecurity. This should include capacity–building and empowering women for wealth generation, improve access to water treatment equipment as well as prioritising improvement of infrastructure that brings piped and safe water to female-headed households.

Can management of ‘thirsty’ alien trees improve water security in semi-arid India?

Arid and semi-arid regions of central India receive scarce and episodic precipitation during the short monsoon season, and also experience substantial evaporation. Traditional and innovative water harvesting and governance practices improve water stewardship, or abate some impacts of intensive mechanised water extraction. However, significant numbers of alien trees, in particular Eucalyptus species with high water demands, populate some regions practicing progressive water stewardship. The water demands of these trees can potentially undermine efforts to achieve water security. Through interviews with community leaders in Indian villages with differing eucalyptus tree densities, water loss through evapotranspiration compared with livelihood demands was approximated. Literature review of the water demands and ecosystem services provided respectively by alien eucalypts and native, culturally valued neem trees supports assessment of the likely benefits and acceptability of a replacement programme favouring native trees. Although data limitations mean that the findings of this study are necessarily uncertain, they nonetheless illustrate the likely scale of impact, substantiating the case for alien tree management as an important contribution to water security. Alien vegetation management practices as a contribution to water security are already firmly established in South Africa, and are likely to yield equivalent benefits if translated to dryland India.

Water insecurity: An agenda for research and call to action for human biology.

Water insecurity-the lack of adequate and safe water for a healthy and productive life-is one of the greatest threats facing humans in the coming century. By 2030, half of the world is expected to be living in water-stressed conditions, given current climate change scenarios. A key goal of the UN Water Action Decade and Sustainable Development Goal 6 is to improve water security for the three billion people globally affected, but the future looks grim. For many communities, from Cape Town, South Africa to Flint, United States, the imagined dystopian future of severe water shortages has already arrived-shaped not so much by lack of water, but by aging infrastructure, underfunded utilities, social exclusion, politicized commodification, and environmental racism. Stepping off from my biocultural research in Cochabamba, Bolivia, I discuss how recent research is dramatically advancing our understanding of water insecurity, such as new findings around the biocultural causes and consequences of dehydration, contamination, and water stress. But, much more needs be done to support local communities in creating fair and just water systems. I discuss how human biologists can make crucial contributions toward the advancement of a much-needed science of water insecurity, while highlighting some practical and ethical challenges to advancing a core mission of providing safe, sufficient water to all.

Evaluation of remotely sensed precipitation estimates using PERSIANN-CDR and MSWEP for spatio-temporal drought assessment over Iran

Satellite Rainfall Estimates (SREs) can provide rainfall information at finer spatial and temporal resolutions, however their performance varies with respect to gauged precipitation data in different climatic regions. A limited number of studies investigated the performance of SREs for spatio-temporal (regional) drought analysis, which is a key component for developing tools for regional drought planning and management. In this study, the performance of two recent SREs (data length > 30 years), which includes Artificial Neural Networks Climate Data Record (PERSIANN-CDR) and the Multi-Source Weighted-Ensemble Precipitation (MSWEP) are selected for spatio-temporal drought assessment over different climatic regions located in Iran. Firstly, the accuracy of SREs was evaluated for deriving standardized precipitation index (SPI) at different time scales (1, 3, 6, 9 and 12 months) for four climatic regions during the period of 1983–2012. Secondly, the performance of SREs was evaluated for regional drought assessment based on the concept of the Severity-Areal-Frequency (SAF) curves. It was observed that the performance of SREs can be different with respect to gauge data in terms of quantifying drought characteristics (e.g., severity, duration, and frequency), identification of major historical droughts, and a significant difference can be observed based on the SAF analysis. For example, the number of drought events based on shorter time scales (SPI-1 and 3) found to be greater for SREs in comparison to gauge information for all climatic regions. While investigating the major historical droughts, discrepancies can be observed between these two types of data sets. For example, gauge data suggests wetness (i.e., SPI-3 > 0.5) near southern Iran, whereas, SREs show droughts (SPI < -1.0) in the same spatial domain. The performance of SREs with respect to gauge data varies largely in terms of quantifying the frequency component embedded in the SAF curves for selected climatic regions located in Iran. Our research findings can be useful for drought assessment in ungagged basins, as well as to develop regional drought management plans to improve water security by integrating multivariate nature of drought events.

Collaboration and Conflict—Developing Forest Restoration Techniques for Northern Thailand’s Upper Watersheds Whilst Meeting the Needs of Science and Communities

This paper describes an early example of Forest Landscape Restoration (FLR), which resulted from collaboration between a university, local community, and national park authority in the upper Mae Sa Valley, near Chiang Mai City, northern Thailand. Working together, the Hmong community of Ban Mae Sa Mai, Doi Suthep National Park Authority and Chiang Mai University’s Forest Restoration Research Unit (FORRU-CMU) established a chronosequence of trial restoration plots from 1996 to 2013, to test the framework-species method of forest restoration. The project developed successful restoration techniques and gained insights into the factors that influence villagers’ participation in forest restoration. Recovery of forest biomass, carbon storage, structure, biodiversity and ecological functioning exceeded expectations. Villagers appreciated the improved water security resulting from the project, as well as a better relationship with the park authority and increased land security. Recently, however, tree chopping and a breakdown in fire-prevention measures (perhaps symptoms of “project fatigue”) have threatened the sustainability of the plot system. The project demonstrates the importance of a sound scientific basis for forest restoration projects, long-term institutional support, and appropriate funding mechanisms, to achieve sustainability.

A modelling approach to improving water security in a drought-prone area, West Coast, South Africa

Due to severe droughts and rapid urbanization, Cape Town municipality including small towns along the West Coast of South Africa are facing water shortages. Managed aquifer recharge (MAR) seems to offer a solution to improve water security in this drought-prone area. This paper presents a conceptual framework within which numerical modelling of the aquifers system is operated to improve water security of West Coast. The ModelMuse software that included MODFLOW and MODPATH packages was used. Scenarios which considered recharge aspects were used to evaluate suitable sites and appropriate scheme of implementing MAR. The result showed that it is feasible to implement MAR in the upper unconfined aquifer unit (UAU) which had estimated available space for MAR of 915.7 million m3. For the semi-confined lower aquifer unit (LAU), the clay-missing window area located at west of Hopefield was a suitable site to implement MAR. However, the prevailing little space in LAU to store recharged water was a limiting factor to support the implementation of MAR scheme. Details on the possibility of implementing MAR scheme for West Coast aquifers system were discussed based of the simulations that were carried out. Although the modelling approach does not provide precise areas but a management tool, it provides key insights that are applicable in aquifer systems of similar characteristics.

Site Assessment for MAR through GIS and Modeling in West Coast, South Africa

Towns along the West Coast of South Africa are facing water shortages due to climate change and increasing water demand. Managed aquifer recharge (MAR) is considered as a solution to improve water security. This paper presents a two-step method of combining geographic information system (GIS) based analysis with numerical modeling to select suitable sites for implementing MAR in the West Coast area. Many factors were taken into account to generate the initial map for suitable sites through GIS based analysis. Subsequently, groundwater flow modeling was adopted to verify and optimize the suitable sites selected by GIS based analysis. The result showed that the map for suitable sites produced by the GIS based analysis was reasonable from a spatial aspect, but due to the lack of groundwater seepage information, the most suitable sites developed are not necessarily the optimal choices in practice. With the aid of both the spatial analysis in GIS and seepage simulation, this two-step analysis approach provides a reliable solution to identify suitable sites for implementing MAR. This approach provides a much better reference to the study of suitable sites and possible impacts of implementing MAR in an aquifer in similar areas with water stress.

Impacts of Soil Phosphorus Drawdown on Snowmelt and Rainfall Runoff Water Quality.

Managing P export from agricultural land is critical to address freshwater eutrophication. However, soil P management, and options to draw down soil P have received little attention in snowmelt-dominated regions because of limited interaction between soil and snowmelt. Here, we assessed the impacts of soil P drawdown (reducing fertilizer P inputs combined with harvest removal) on soil Olsen P dynamics, runoff P concentrations, and crop yields from 1997 to 2014 in paired fields in Manitoba, Canada. We observed that Olsen P concentrations in the 0- to 5-cm soil layer were negatively correlated with the cumulative P depletion and declined rapidly at the onset of the drawdown practice (3.1 to 5.4 mg kg yr during 2007-2010). In both snowmelt runoff and rainfall runoff, concentrations of total dissolved P (TDP) were positively correlated with the concentrations of soil Olsen P. Soil P drawdown to low to moderate fertility levels significantly decreased mean annual flow-weighted TDP concentrations in snowmelt runoff from 0.60 to 0.30 mg L in the field with high initial soil P and from 1.17 to 0.42 mg L in the field with very high initial soil P. Declines in TDP concentration in rainfall runoff were greater. Critically, yields of wheat ( spp.) and canola ( L.) were not affected by soil P depletion. In conclusion, we demonstrate that relatively rapid reductions in P loads are achievable at the field scale via managing P inputs and soil P pools, highlighting a management opportunity that can maintain food security while improving water security in cold regions.