Complex River Basin Research Articles

Changes in Snow Cover Dynamics over the Indus Basin: Evidences from 2008 to 2018 MODIS NDSI Trends Analysis

The frozen water reserves on the Earth are not only very dynamic in their nature, but also have significant effects on hydrological response of complex and dynamic river basins. The Indus basin is one of the most complex river basins in the world and receives most of its share from the Asian Water Tower (Himalayas). In such a huge river basin with high-altitude mountains, the regular quantification of snow cover is a great challenge to researchers for the management of downstream ecosystems. In this study, Moderate Resolution Imaging Spectroradiometer (MODIS) daily (MOD09GA) and 8-day (MOD09A1) products were used for the spatiotemporal quantification of snow cover over the Indus basin and the western rivers’ catchments from 2008 to 2018. The high-resolution Landsat Enhanced Thematic Mapper Plus (ETM+) was used as a standard product with a minimum Normalized Difference Snow Index (NDSI) threshold (0.4) to delineate the snow cover for 120 scenes over the Indus basin on different days. All types of errors of commission/omission were masked out using water, sand, cloud, and forest masks at different spatiotemporal resolutions. The snow cover comparison of MODIS products with Landsat ETM+, in situ snow data and Google Earth imagery indicated that the minimum NDSI threshold of 0.34 fits well compared to the globally accepted threshold of 0.4 due to the coarser resolution of MODIS products. The intercomparison of the time series snow cover area of MODIS products indicated R2 values of 0.96, 0.95, 0.97, 0.96 and 0.98, for the Chenab, Jhelum, Indus and eastern rivers’ catchments and Indus basin, respectively. A linear least squares regression analysis of the snow cover area of the Indus basin indicated a declining trend of about 3358 and 2459 km2 per year for MOD09A1 and MOD09GA products, respectively. The results also revealed a decrease in snow cover area over all the parts of the Indus basin and its sub-catchments. Our results suggest that MODIS time series NDSI analysis is a useful technique to estimate snow cover over the mountainous areas of complex river basins.

Defining Robustness, Vulnerabilities, and Consequential Scenarios for Diverse Stakeholder Interests in Institutionally Complex River Basins

AbstractThe Upper Basin of the Colorado River in the southwestern United States supports municipal, industrial, agricultural, and recreational activities worth an estimated $300 billion/year within the state of Colorado alone. The allocation of water to these activities is fundamentally shaped by water rights that in turn distribute risks among a diverse suite of sectors and stakeholders. In this study, we assess the vulnerabilities faced by the hierarchy of hundreds of water users in the portion of the Upper Basin within the state of Colorado, as a result of changes in hydrologic extremes, demand growth, and institutional and physical infrastructure in the basin. We also determine how robust the different users are to these potential changes, examining how their sensitivity to these factors depends on the magnitude and frequency of shortage they are unwilling to exceed. This advances previous robustness evaluation methods by formalizing an a posteriori exploration of alternative definitions of robustness tailored to each user's unique context. Our analysis reveals that robustness varies significantly not only across users but also across different definitions of acceptable performance for each user. We further show the importance of using scenario discovery to evaluate how the factors that drive consequential scenarios differ depending on the definition of robustness. Our results highlight the need for robustness and vulnerability frameworks to avoid broad categorical aggregations of stakeholder groups, to carefully capture complex institutional dependencies (e.g., water rights), and to facilitate a more transparent illustration of the implications of alternative definitions of robustness for specific stakeholders.

Low snowpack reduces thermal response diversity among streams across a landscape

AbstractSpatial and temporal variation in thermal conditions are important dimensions of aquatic landscapes, yet we do not understand how this heterogeneity will respond to climate change. Snowpack in many regions is declining but impacts on aquatic thermal regimes remain poorly understood. Our analyses of summer stream temperatures across a complex river basin in southwest Alaska show that loss of snowpack has disproportionate effects on water temperatures in streams that are cold under typical conditions, thereby homogenizing stream temperatures across the landscape during low snow conditions. Streams draining steep watersheds warmed from a summer average of 4–8°C between high and low snow years and became more responsive to variation in regional air temperature (as proxy for solar radiation), while streams draining flat watersheds changed negligibly. Our results suggest that conservation strategies for aquatic landscapes that focus on snow‐dominated cold‐water refugia may not be robust to future climate warming and changes in snowpack.

Evaluating the effectiveness of the pollutant discharge permit program in China: A case study of the Nenjiang River Basin

China is continually seeking to improve river water quality. Implemented in 1996, the total pollutant load control system (TPLCS) is a regulatory strategy to reduce total pollutant loads, under which a Pollutant Discharge Permit (PDP) program tracks and regulates nutrient inputs from point source polluters. While this has been promising, the input-response relationship between discharge permits and water quality targets is largely unclear – especially in China's large and complex river basins. In response, this study involved a quantitative analysis method to combine the water quality targets of the 12th Five-Year Plan (2011–2015) with allocated PDPs in the Nenjiang River Basin, China. We demonstrated our approach by applying the Soil and Water Assessment Tool (SWAT) to the Nenjiang River Basin for hydrological and water quality simulation. Ammonia nitrogen (NH3-N) was used as the primary water quality indicator. Modelling indicated that only one control section in the wider river basin did not achieve the water quality target, suggesting that the TPLCS is largely effective. The framework should be applied in other basins to study the effectiveness of PDP policies, advise further updates to the TPLCS, and ultimately aim to achieve freshwater quality targets nationally.

Incorporating the logistic regression into a decision-centric assessment of climate change impacts on a complex river system

Abstract. Climate change is a global stressor that can undermine water management policies developed with the assumption of stationary climate. While the response-surface-based assessments provided a new paradigm for formulating actionable adaptive solutions, the uncertainty associated with the stress tests poses challenges. To address the risks of unsatisfactory performances in a climate domain, this study proposed the incorporation of the logistic regression into a decision-centric framework. The proposed approach replaces the “response surfaces” of the performance metrics typically used for the decision-scaling framework with the “logistic surfaces” that describes the risk of system failures against predefined performance thresholds. As a case study, water supply and environmental reliabilities were assessed within the eco-engineering decision-scaling framework for a complex river basin in South Korea. Results showed that human-demand-only operations in the river basin could result in the water deficiency at a location requiring environmental flows. To reduce the environmental risks, the stakeholders could accept increasing risks of unsatisfactory water supply performance at the sub-basins with small water demands. This study suggests that the logistic surfaces could provide a computational efficiency to measure system robustness to climatic changes from multiple perspectives together with the risk information for decision-making processes.

Trace Metal Modelling of a Complex River Basin Using the Suite of Models Integrated in the OpenMI Platform

Modelling trace metal dynamics is essential in an integrated modelling framework as trace metals have the potential to be fatal, even when present at low concentrations. Since the degree of bioavailability of a metal depends on its presence in the dissolved phase, it is necessary to keep track of both the dissolved and particulate phase of metals. In general, the well-known partitioning coefficient approach is widely used for trace metal speciation. As such, we applied a parametric approach to relate the partitioning coefficient to several environmental variables. These environmental variables are made available by a suite of physically based models (a hydrologic and diffuse pollution model, Soil and Water Assessment Tool (SWAT); a hydraulic model, Storm Water Management Model (SWMM); a stream temperature model; an in-stream water quality conversion model; and a sediment transport model) integrated using the Open Modelling Interface (OpenMI). For trace metal speciation, two regression techniques, (a) the multi-linear regression (MLR) and (b) the principle component regression (PCR), were used. It is then tested in the Zenne river basin, Belgium, to simulate four trace metals (copper, cadmium, zinc and lead) dynamics. We demonstrated the usefulness of the OpenMI platform to link different model components for integrated trace metal transport modelling of a complex river basin. It was found that the integrated model simulated different metals with ‘satisfactory’ accuracy. The MLR- and PCR-based model results were also comparable. From a management perspective, the river is not heavily polluted except for the level of dissolved zinc. We believe that the availability of such a model will allow for a better understanding of trace metal dynamics, which could be utilized to improve the present condition of the river.

An adapted companion modelling approach for enhancing multi-stakeholder cooperation in complex river basins

ABSTRACTThe sustainable development agenda 2030 calls for achievement of certain targets to ensure access to water and sanitation for all. Multi-stakeholder partnerships and the use of data and modelling tools are conditioning elements for their achievement. In this article, we demonstrate that participatory modelling supports informed and participatory decision making in complex river basins. An adapted companion modelling approach is presented to support collective action by reducing disputes and enhancing collaboration among stakeholders. The co-development and use of empirical models for understanding the complexity of the physical system is combined with the use of role-playing games to ensure the active involvement of stakeholders. The approach is implemented in a top-down water quality planning process in Turkey. Results show its suitability for managing water quality in complex river basins in an inclusive manner and its substantial benefits in developing stakeholders’ capacities and creating a cooperative environment.

Socio‐Hydrology of Channel Flows in Complex River Basins: Rivers, Canals, and Distributaries in Punjab, Pakistan

AbstractThis paper presents a socio‐hydrologic analysis of channel flows in Punjab province of the Indus River basin in Pakistan. The Indus has undergone profound transformations, from large‐scale canal irrigation in the mid‐nineteenth century to partition and development of the international river basin in the mid‐twentieth century, systems modeling in the late‐twentieth century, and new technologies for discharge measurement and data analytics in the early twenty‐first century. We address these processes through a socio‐hydrologic framework that couples historical geographic and analytical methods at three levels of flow in the Punjab. The first level assesses Indus River inflows analysis from its origins in 1922 to the present. The second level shows how river inflows translate into 10‐daily canal command deliveries that vary widely in their conformity with canal entitlements. The third level of analysis shows how new flow measurement technologies raise questions about the performance of established methods of water scheduling (warabandi) on local distributaries. We show how near real‐time measurement sheds light on the efficiency and transparency of surface water management. These local socio‐hydrologic changes have implications in turn for the larger scales of canal and river inflow management in complex river basins.

Integrating river basin DSSs with model checking

This paper presents a decision support system (DSS) based on formal methods for the management of complex river basins in flood scenarios. The DSS is the result of integrating two different DSSs: first, a DSS for dam management that uses the Spin model checker to produce the manoeuvres and the discharged water over time to satisfy user-defined constraints; second, a DSS that performs numeric simulations of rainfall and water flow along the river basin, taking into account the water discharged by dams. By integrating these two DSSs, the user can define constraints over the parameters of the river basin and all the dams. We use Spin to find the sequences of dam manoeuvres that mitigate the effect of floods along the river basin, according to these constraints. This work is part of the SAID project, a European demonstration project whose main goal is to smartly manage river basins by means of the integration of different DSSs. The demonstrator basin is the Guadalhorce river basin, located in the south of Spain. We apply the method to develop a DSS for this river basin in particular, but the approach is general enough that it can be applied to any river basin.

Modeling multidecadal surface water inundation dynamics and key drivers on large river basin scale using multiple time series of Earth‐observation and river flow data

AbstractPeriodically inundated floodplain areas are hot spots of biodiversity and provide a broad range of ecosystem services but have suffered alarming declines in recent history. Despite their importance, their long‐term surface water (SW) dynamics and hydroclimatic drivers remain poorly quantified on continental scales. In this study, we used a 26 year time series of Landsat‐derived SW maps in combination with river flow data from 68 gauges and spatial time series of rainfall, evapotranspiration and soil moisture to statistically model SW dynamics as a function of key drivers across Australia's Murray‐Darling Basin (∼1 million km2). We fitted generalized additive models for 18,521 individual modeling units made up of 10 × 10 km grid cells, each split into floodplain, floodplain‐lake, and nonfloodplain area. Average goodness of fit of models was high across floodplains and floodplain‐lakes (r2 > 0.65), which were primarily driven by river flow, and was lower for nonfloodplain areas (r2 > 0.24), which were primarily driven by rainfall. Local climate conditions were more relevant for SW dynamics in the northern compared to the southern basin and had the highest influence in the least regulated and most extended floodplains. We further applied the models of two contrasting floodplain areas to predict SW extents of cloud‐affected time steps in the Landsat series during the large 2010 floods with high validated accuracy (r2 > 0.97). Our framework is applicable to other complex river basins across the world and enables a more detailed quantification of large floods and drivers of SW dynamics compared to existing methods.

An Ecosystem Health Index for a large and variable river basin: Methodology, challenges and continuous improvement in Queensland’s Fitzroy Basin

Report cards are an increasingly popular method for summarising and communicating relative environmental performance and ecosystem health, including in aquatic environments. They are usually underpinned by an Ecosystem Health Index (EHI) that combines various individual indicators to produce an overall ecosystem health “score”. As a result of public water quality concerns, an integrated means of monitoring and reporting on aquatic ecosystem health was needed for the Fitzroy Basin in central Queensland, Australia. The Fitzroy Partnership for River Health was formed to address this need, and developed an EHI and report card for the Basin using existing monitoring data collected from various third parties including regulated companies operations and government. At 142,000 square kilometres, the Fitzroy Basin is the largest catchment draining to the World Heritage Listed Great Barrier Reef. The Fitzroy Basin provides an example of how to deliver an effective aquatic ecosystem health reporting system in a large and complex river basin. We describe the methodology used to develop an adaptive EHI for the Fitzroy Basin that addresses variability, complexity and scale issues associated with reporting across large areas. As well, we report how to manage the design and reporting stages given limitations in data collection and scientific understanding.

Hydro-economic modeling with aquifer–river interactions to guide sustainable basin management

Policymakers in arid and semiarid basins face hard choices on water policies needed for adaptation to climate change. Hydro-economic modeling is a state-of-the art approach that can be used to guide the design and implementation of these policies in basins. A major gap in developments of hydro-economic modeling to date has been the weak integration of physically-based representations of water sources and uses such as the interaction between ground and surface water resources, to inform complex basin scale policy choices. This paper presents an integrated hydro-economic modeling framework to address this gap with application to an important and complex river basin in Spain, the Jucar basin, for the assessment of a range of climate change scenarios and policy choices. Results indicate that in absence of adequate policies protecting water resources and natural ecosystems, water users will strategically deplete reservoirs, aquifers and river flows for short-term adaptation to climate change, disregarding the impacts on the environment and future human activities. These impacts can be addressed by implementing sustainable management policies. However, these policies could have disproportionate costs for some stakeholders groups, and their opposition may undermine attempts at sustainable policy. These tradeoffs among water policy choices are important guides to the design of policies aimed at basin-wide adaptation to climate change.

Sustaining local values through river basin governance: community-based initiatives in Australia's Murray–Darling basin

Australia's Murray–Darling basin (MDB) water plan is an ambitious attempt to balance ecological, social and economic benefits, where a key aspect of the reform process has been recovery of water for environmental use. This paper focuses on a set of initiatives established by a local non-governmental organisation and an Indigenous community designed to engage with local values and priorities and incorporate them into this complex river basin governance system. Contrary to expectations that local and basin-scale interests and outcomes will diverge, the case studies reveal the ability for local groups to collaboratively manage both land and water resources to achieve locally important outcomes, and contribute to basin-scale outcomes. The analysis also highlights a progressive style of community-based environmental management for water management that utilises multiple institutional arrangements and planning pathways to protect the values that are important to local communities, and to nest those values within the broader effort to sustainably manage the basin's water resources.

Many‐objective reservoir policy identification and refinement to reduce policy inertia and myopia in water management

AbstractThis study contributes a decision analytic framework to overcome policy inertia and myopia in complex river basin management contexts. The framework combines reservoir policy identification, many‐objective optimization under uncertainty, and visual analytics to characterize current operations and discover key trade‐offs between alternative policies for balancing competing demands and system uncertainties. The approach is demonstrated on the Conowingo Dam, located within the Lower Susquehanna River, USA. The Lower Susquehanna River is an interstate water body that has been subject to intensive water management efforts due to competing demands from urban water supply, atomic power plant cooling, hydropower production, and federally regulated environmental flows. We have identified a baseline operating policy for the Conowingo Dam that closely reproduces the dynamics of current releases and flows for the Lower Susquehanna and thus can be used to represent the preferences structure guiding current operations. Starting from this baseline policy, our proposed decision analytic framework then combines evolutionary many‐objective optimization with visual analytics to discover new operating policies that better balance the trade‐offs within the Lower Susquehanna. Our results confirm that the baseline operating policy, which only considers deterministic historical inflows, significantly overestimates the system's reliability in meeting the reservoir's competing demands. Our proposed framework removes this bias by successfully identifying alternative reservoir policies that are more robust to hydroclimatic uncertainties while also better addressing the trade‐offs across the Conowingo Dam's multisector services.

Water Accounting Plus (WA+) – a water accounting procedure for complex river basins based on satellite measurements

Abstract. Coping with water scarcity and growing competition for water among different sectors requires proper water management strategies and decision processes. A pre-requisite is a clear understanding of the basin hydrological processes, manageable and unmanageable water flows, the interaction with land use and opportunities to mitigate the negative effects and increase the benefits of water depletion on society. Currently, water professionals do not have a common framework that links depletion to user groups of water and their benefits. The absence of a standard hydrological and water management summary is causing confusion and wrong decisions. The non-availability of water flow data is one of the underpinning reasons for not having operational water accounting systems for river basins in place. In this paper, we introduce Water Accounting Plus (WA+), which is a new framework designed to provide explicit spatial information on water depletion and net withdrawal processes in complex river basins. The influence of land use and landscape evapotranspiration on the water cycle is described explicitly by defining land use groups with common characteristics. WA+ presents four sheets including (i) a resource base sheet, (ii) an evapotranspiration sheet, (iii) a productivity sheet, and (iv) a withdrawal sheet. Every sheet encompasses a set of indicators that summarise the overall water resources situation. The impact of external (e.g., climate change) and internal influences (e.g., infrastructure building) can be estimated by studying the changes in these WA+ indicators. Satellite measurements can be used to acquire a vast amount of required data but is not a precondition for implementing WA+ framework. Data from hydrological models and water allocation models can also be used as inputs to WA+.

Upper and Middle Tiete River Basin dam-hydraulic system, travel time and temperature modeling

Summary Tiete River System in the State of Sao Paolo, Brazil is characterized by complex hydraulics and operational problems due to series of dams and point and diffuse inflows along the river. A one dimension Lagrangian river model was developed and applied to the 313 km reach of the Upper and Middle Tiete River Basin from the Penha Dam to the head water of Bara Bonita Reservoir, a stretch of river that includes six small to medium size dams (3.4–22 m high) including the Pirapora Reservoir and 26 inflows into the river (11 tributaries, 9 diffuse source areas, and discharges of 4 cities stormwater and 2 wastewater treatment plants. The conservative tracer transport and temperature model that accounts for the short and long wave radiation and heat transfers at the free surface was included and solved using the Crank–Nicholson scheme. The time variable catchment input to the model was the simulated output of the external hydrological model called Runoff Load Model which results were provided by CETESB. The numerical treatment of series of dams and spillway (that included uncontrolled overflow spillway, gate-controlled ogee spillway; and underflow gates and tunnels) and parameterisation of hydraulic jumps are described. Special attention was focused on the high spatial and temporal variation of flows in Tiete River Basin, a result of the large variation in catchment inflows and channel geometry due to dams and reservoirs along the river. Predicted and measured spatial and seasonal variation of flow and temperature profiles along the river show good agreement. The simulated travel time of conservative tracer is compared against the CETESB’s 1982 and 1984 field study data in a 254 km reach of the Middle Tiete River that again shows good agreement. Being Lagrangian in construction, this new model is computationally efficient making it an ideal tool for long term simulation for water resource planning, management and operation decision making in a large and complex river basin system.

Cost–Effectiveness Analysis of Water Management Measures in Two River Basins of Jordan and Lebanon

Chekka Bay area and Amman Zarqa Basin are two complex river basins in northern Lebanon and northern Jordan respectively. Both regions are faced with growing populations, urban development and land-use changes. They also both suffer from water-resource scarcity and contrasted seasons that threaten the perennity of sufficient water supply. Decision makers may have several water-management measures in response to the issue of water deficiency in their regions, but they need simple methods and criteria for ranking the alternatives with respect to their economical efficiency. In this paper, the Cost–Effectiveness Analysis method is used for supporting decisions to optimally combine water management measures at the river basin scale. Hydrologic and socio-economic data are used for assessing the future water balance and determine the sustainable management objectives. Both supply- and demand-side measures are investigated and compared. The analysis is based on two basic metrics to assess cost–effectiveness ratios: the average annualized and the marginal (or incremental) unit cost. The results show that the cost–effectiveness ranking of alternative measures strongly depends on the selected metric. The average annualized unit cost systematically favours large scaled water measures with high costs while the average incremental unit cost facilitates the selection of smaller and costless measures reflecting the time preference for water supply.

Basin-scale reconstruction of the geological context of human settlement: an example from the lower Mississippi Valley, USA

Large river valleys integrate hydroclimatic change differently than smaller ones. Whereas sedimentary deposits in smaller valleys serve to record temporally short-lived and/or low-amplitude hydrological and geomorphic responses, larger valleys are relatively insensitive to changes at these scales. However, because of their size, larger valleys archive sedimentary records of longer-term, geographically extensive flooding and climate-related landscape evolution. Recent work in the Upper Tensas Basin of the lower Mississippi River Valley, USA, demonstrates the utility of analyzing sediments from a large, geomorphically and fluvially complex river basin as a proxy for significant climatic and landscape changes and their relation to human history. A ∼6000 year sedimentary archive is used to explore the interplay between climate change, landscape evolution, and human responses to changing environmental parameters. Once the Mississippi River basin stabilized following glacial retreat and deceleration of sea-level rise, the history of the river and its inhabitants was dominated by long periods of landscape stability punctuated by episodes of significant landform alteration. Modifications of the landscape are correlated with intervals of rapid climate change recorded in globally distributed multiproxy data sets. Periods of significant landscape instability and fluvial re-adjustment are recorded for the periods ca 4800–3800, 3000–2500, and 1000–800 cal BP. These punctuations in the history of the lower Mississippi Valley are related to periods of major cultural transformation and suggest climate change plays a significant role in the long-term history of human occupation in this river valley. This research demonstrates how geoarcheology can provide information on human–environmental relationships and long-term landscape histories at temporal and spatial scales relevant to understanding cultural responses to climate change.

The characteristics of flood responses to the restoration of polders on Dongting Lake, China

The serious shrinkage of Dongting Lake in China has led to the deterioration of its flood diversion and storage capacity, and now flood disasters have become more frequent. A lake restoration strategy is proposed in order to relieve flood-prone areas. However, flood movement is a dynamic process, so that approaches neglecting the hydrodynamics cannot accurately represent flood responses to restoring polders to a lake in a complex river basin. Here, a coupled one-dimensional and two-dimensional hydrodynamic model was applied to investigate flood responses to restoring polders to Dongting Lake under the conditions of the 1998 flood event. Quantified flood reduction effects show that the characteristics of flood responses vary significantly with the management option chosen. Appropriate strategies of lake restoration are suggested according to different flood responses. Polders of type II, which favour flood discharge, should be restored in order to streamline flood conveyance. Considering the ecological requirements of the lakes and wetlands, type I polders far from main flows can be partially restored, resulting in evacuation of residents to safe areas but keeping the cultivation.

Coupling upland watershed and downstream waterbody hydrodynamic and water quality models (SWAT and CE-QUAL-W2) for better water resources management in complex river basins

Effective water resources management programs have always incorporated detailed analyses of hydrological and water quality processes in the upland watershed and downstream waterbody. We have integrated two powerful hydrological and water quality models (SWAT and CE-QUAL-W2) to simulate the combined processes of water quantity and quality both in the upland watershed and downstream waterbody. Whereas the SWAT model outputs water quality variables in its entirety, the CE-QUAL-W2 model requires inputs in various pools of organic matter contents. An intermediate program was developed to extract outputs from SWAT at required subbasin and reach outlets and converts them into acceptable CE-QUAL-W2 inputs. The CE-QUAL-W2 model was later calibrated for various hydrodynamic and water quality simulations in the Cedar Creek Reservoir, TX, USA. The results indicate that the two models are compatible and can be used to assess and manage water resources in complex watersheds comprised of upland watershed and downstream waterbodies.