GRACE Follow-On revealed Bangladesh was flooded early in the 2020 monsoon season due to premature soil saturation

The overall size and timing of monsoon floods in Bangladesh are challenging to measure. The inundated area is extensive in low-lying Bangladesh, and observations of water storage are key to understanding floods. Laser-ranging instruments on Gravity Recovery and Climate Experiment (GRACE) Follow-On spacecraft detected the peak water storage anomaly of 75 gigatons across Bangladesh in late July 2020. This is in addition to, and three times larger than, the maximum storage anomaly in soil layers during the same period. A flood propagation model suggested that the water mass, as shown in satellite observations, is largely influenced by slow floodplain and groundwater flow processes. Independent global positioning system measurements confirmed the timing and total volume of the flood water estimates. According to land surface models, the soils were saturated a month earlier than the timing of the peak floodplain storage observed by GRACE Follow-On. The cyclone Amphan replenished soils with rainfall just before the monsoon rains started, and consequently, excessive runoff was produced and led to the early onset of the 2020 flooding. This study demonstrated how antecedent soil moisture conditions can influence the magnitude and duration of flooding. Continuous monitoring of storage change from GRACE Follow-On gravity measurements provides important information complementary to river gauges and well levels for enhancing hydrologic flood forecasting models and assisting surface water management.

Enhancing the Visibility of SuDS in Strategic Planning Using Preliminary Regional Opportunity Screening

Surface water flooding poses significant threats to communities and environments. This threat has historically been managed through sewers and combined sewer overflows; however, it is now well recognised that, alone, these legacy systems are insufficient to manage the growing pressures from climate change, population growth and urbanisation. This realisation has led to research and practice developing a broad range of new technologies to enhance the coping capacities of existing sewer systems through capturing and attenuating or reusing surface water across catchments using sustainable drainage systems (SuDS). However, despite technical understanding, industry champions and significant best practice, SuDS remain underutilised, particularly at a synergistic catchment scale where they can be most effective. In this paper we respond to this challenge by developing preliminary screening tools to enhance the visibility of SuDS among the multidisciplinary decision-makers responsible for directing strategic surface water management. We achieve this through upscaling a regional decision support model and demonstrating implementation across a case study in South West England. We find that it is possible to use easily accessible and open-source data to provide initial indications of SuDS opportunities and that this early visibility in the decision-making process can be used to support the consideration of novel and effective surface water management strategies.

The Management of the Water as an Effort to Realize a Green Campus in Universitas Sebelas Maret Surakarta

The main campus of UNS Surakarta, occupies an area of ± 59,211 Ha. At present, the problem faced by UNS is the increasing of narrow green space, so that it increases rain water and lead to runoff. This process has an impact on the increase in flood discharge and the reduction in the supply of rainwater which becomes ground water reserves. In order to realize a Green Campus that supports sustainable development, efforts have been made relating to groundwater and surface water management. A total of 117 infiltration wells and more than 500 biopori infiltration units have been built, which serve to increase shallow groundwater reserves so that it increases rainwater harvesting and soil moisture. Rainwater that cannot be accommodated in infiltration wells is channeled to the lake named Danau UNS which has an area of 1,206 Ha with a maximum water volume of ± 7,959 m3 , so that it is expected to be able to maintain the shallow ground water balance at the Kentingan UNS Campus. In the future planning, Universitas Sebelas Maret will improve domestic wastewater treatment for other uses, so that there is an efficient use of sustainable clean water

From site-focused intervention towards landscape-scale surface water management using Synthetic Stream Networks and Rapid Scenario Screening

This research addresses the need to transform success in technical understanding and practical implementation of surface water management (SWM) interventions at a site-scale towards integrated landscape-scale management. We achieve this through targeting the informative preliminary stages of strategic design, where broad, early and effective exploration of opportunities can enhance and direct a regional SWM perspective. We present a new method, ‘Synthetic Stream Networks’ (SSN), capable of meeting these requirements by taking advantage of easily accessible data, likely to be available during regional screening. We find that results from the SSN are validated by existing, ‘downstream’ focused data (90% of the river network is within 30 m of an associated SSN flow path), with the added advantage of extending understanding of surface water exceedance flow paths and watersheds into the upper catchment, thus establishing a foundational and physically based sub-catchment management unit exploring surface water connectivity at a catchment and landscape scale. We also demonstrate collaborative advantages of twinning the new SSN method with ‘Rapid Scenario Screening’ (RSS) to develop a novel approach for identifying, exploring and evaluating SWM interventions. Overall, we find that this approach addresses challenges of integrating understanding from sub-catchment, catchment and landscape perspectives within surface water management.

The Water Management Regime in Western Iran: A Retrospective Analysis through a Hybrid Transitions Framework

Continuously changing conditions of sociotechnical systems are the basis of structural changes in communities. Relationships between transition contexts and regime transformation processes and their driving factors in sociotechnical regimes are poorly understood. Moreover, not all changes in multilevel governance regimes are geared towards sustainability, as demonstrated by the case of the water management regime in Sanandaj county in the west of Iran between 1962 and 2018. The current study shows how the management regime of water resources in the case study has changed over time and identifies the institutional arrangements through a retrospective analysis. The analysis is based on three stages of data collection which included a discussion group, a Delphi survey, and a focus group survey among various types of stakeholders. The “Hybrid Transitions” framework is introduced in order to denote processes of regime change that take place in a range of different transition contexts. The findings do not identify a single transition pathway but show that a number of parallel transition pathways have occurred in the context of groundwater and surface water management and their respective institutional arrangements. The study provides a better understanding of the complexity of transition pathways that were devised at the management regime level.

National Green Infrastructure Facility – a specialised ‘living laboratory’ to assess the value of urban green infrastructure

<p>Green Infrastructure (GI) offers multiple and integrated benefits to urban areas, including relieving pressure on ‘grey’ infrastructure systems by locally managing surface runoff within cities to reduce the risk of urban flooding. Although the use of GI has been shown to attenuate flooding, monitored and quantifiable data determining the effectiveness of GI is imperative for supporting widespread adoption of GI within cities and to provide an evidence-base to inform the design and maintenance procedures of such systems and ultimately influence key decision makers .</p><p>The National Green Infrastructure Facility (NGIF) based in Newcastle-upon-Tyne, UK, is a purpose-built, publicly accessible, ‘living laboratory’ and demonstration site established in 2017, funded by the UK Collaboratorium for Research on Infrastructure and Cities. The NGIF explores how a wide range of green features such as trees, shrubs and soils can help reduce flooding in cities and make them more resilient and sustainable to future changes in climate and urban pressures. The facility hosts a number of novel GI features of varying scale, monitored with dense sensor networks to allow the in-situ measurement of key hydrological, climatic and biophysical variables (e.g. precipitation, temperature, soil moisture, water depth, runoff and outflow rates) which are able to provide quantified evidence of the hydrological performance of sustainable drainage systems (SuDS). Such systems generate detailed insights into how SuDS and nature-based solutions can be used to improve surface water management, optimise geo-energy for building heating/cooling and how systems can be used for urban water treatment.</p><p>GI features across the NGIF include an experimental  and fully functional swale, providing protection to the area of Newcastle-upon-Tyne in which the feature is located, 10 lysimeter bioretention cells, a series of rain-garden ‘ensembles’ and a monitored green roof system. All experimental features are subjected to prevalent environmental conditions and act as fully functional GI systems, but conditions can also be augmented and simulated to ensure that the GI features act as semi-controlled experimental systems to determine responses outside of the natural instrumented record. All environmental data is recorded at high temporal (< 5 minutes) and spatial resolution and is publicly accessible in real-time via the NGIF API.</p><p>This presentation provides an overview of the NGIF and discusses the current research activities taking place across the site. Data is presented from each of the GI systems to demonstrate and discuss their performance and responses during natural and simulated events, including extremes, and to assess their effectiveness in responding to localised changes in climate. Future research directions and collaborative opportunities are also highlighted.</p>

The development of Sponge City Program (SCP) – a transition of urban stormwater management and planning practice in Chinese cities

<p>‘<em>Sponge City Program</em>’ (SCP) is the term used to describe the Chinese government’s approach to urban surface water management. The concept was conceived in 2014 in response to an increasing incidence of urban surface flooding in many Chinese cities. While ambitious and far-reaching in its aim (of reducing national flood risk, increasing water supply and improving water quality), the initiative must be implemented by individual sub-provincial or municipal-level government entities. The concept is similar to <em>Blue-Green Cities</em> (BGCs); <em>sustainable drainage systems</em> (SuDS) in the UK, it is developing with different regional climatic and hydrological characteristics, considering rapid urbanization. Indeed, the increasing use of national rather than international examples of best practice reflects a growing body of knowledge that has evolved since the start of the Sponge City initiative. The SCP so far now has run through 6 years and experience a transition on urban stormwater management and planning practices. In this paper, the implementation of the latest SCP guidelines will be presented that using the case of Ningbo and other Chinese cities to illustrate the transformation of the current SCP practices that undertaking the consideration of climate, environmental and socio-economic factors, and how the practice tackle challenges on governance, project financing, integration and assessment by the authorities and stakeholders. These valuable experiences will be vitally important influencing future urban stormwater management and planning practices in Chinese cities.</p>