Upstream Solutions to Downstream Problems: Investing in Rural Natural Infrastructure for Water Quality Improvement and Flood Risk Mitigation

Communities across the globe are experiencing degraded water quality as well as inland flooding, and these problems are anticipated to worsen with climate change. We review the evidence that implementing natural infrastructure in upstream agricultural landscapes could improve water quality and reduce flood risk for downstream communities. Based on our analysis, we identify a suite of natural infrastructure measures that provide the greatest benefits, and which could be prioritized for investment by downstream communities and regional leadership, with an emphasis on systems that minimize loss of productive agricultural land. Our results suggest that the restoration of wetlands and floodplains are likely to provide the greatest benefits for both water quality improvement and flood risk reduction.

Examining the Xayabouly dam: Impacts of hydropower dam construction on downstream communities

<p>Hydropower power dam development is a booming industry in Laos and it has the potential to tackle poverty in an environmentally sustainable way. However, currently there is a lack of research that thoroughly analyses the negative impacts of a hydropower dam’s construction phase. This research explores some of these negative impacts of hydropower dam construction on downstream villagers by using the Xayabouly hydropower dam on the Mekong River as a case study. Understanding the impacts of the construction phase is vital in forming policy and developing effective strategies to mitigate future negative impacts from dam construction. This thesis employs a qualitative approach and semi-structured interviews were conducted with downstream villagers about these negative impacts. This research is based on a pragmatist epistemology and employs the matrix conceptual framework to guide this thesis. The results from this study show that the Xayabouly hydropower dam’s construction phase has many negative impacts on downstream villagers’ daily lives. For example, the construction phase has caused irregular flooding, which has destroyed downstream villagers’ agricultural gardens and riverbank erosion has also occurred. Moreover, the results from this thesis show that the construction phase of this dam significantly reduced villagers’ income and nutrition consumption. The construction phase also created significant problems with regards to daily commuting and damaged fishing gear. These results offer important recommendations and implications, which have the potential to inform government policy in the future and to help develop strategies to mitigate the social and economic impacts from future hydropower dam construction in Laos.</p>

Examining the Xayabouly dam: Impacts of hydropower dam construction on downstream communities

<p>Hydropower power dam development is a booming industry in Laos and it has the potential to tackle poverty in an environmentally sustainable way. However, currently there is a lack of research that thoroughly analyses the negative impacts of a hydropower dam’s construction phase. This research explores some of these negative impacts of hydropower dam construction on downstream villagers by using the Xayabouly hydropower dam on the Mekong River as a case study. Understanding the impacts of the construction phase is vital in forming policy and developing effective strategies to mitigate future negative impacts from dam construction. This thesis employs a qualitative approach and semi-structured interviews were conducted with downstream villagers about these negative impacts. This research is based on a pragmatist epistemology and employs the matrix conceptual framework to guide this thesis. The results from this study show that the Xayabouly hydropower dam’s construction phase has many negative impacts on downstream villagers’ daily lives. For example, the construction phase has caused irregular flooding, which has destroyed downstream villagers’ agricultural gardens and riverbank erosion has also occurred. Moreover, the results from this thesis show that the construction phase of this dam significantly reduced villagers’ income and nutrition consumption. The construction phase also created significant problems with regards to daily commuting and damaged fishing gear. These results offer important recommendations and implications, which have the potential to inform government policy in the future and to help develop strategies to mitigate the social and economic impacts from future hydropower dam construction in Laos.</p>

Assessing the profitability and sustainability of upland farming systems in Cambantoc subwatershed, Philippines

Deforestation, forest and land degradation affect the provision of ecosystem services in the watersheds of Laguna Lake. The study site, Cambantoc Subwatershed, experiences unsustainable upland farming practices that worsen the flooding situation in the downstream areas. This study analyzed rice monocropping and agroforestry farming systems upstream based on measures of profitability, sustainability, and soil quality using the Benefit-Cost Analysis and Soil Changes Under Agroforestry (SCUAF) model. Data on the costs and benefits of the farming systems and the parameters used in calibrating the model were acquired through interviews and secondary data collection. The study found that monocropping is more profitable while agroforestry has better environmental benefits because it can minimize soil erosion and soil nutrient loss through time. Agroforestry is an ideal example of Nature-Based Solution to achieve sustainable farming and enhance the delivery of ecosystem services such as soil nutrient enrichment in the upstream farms and flood mitigation in the downstream areas. The results of this study can serve as a decision support for the policy makers to consider developing and implementing market-based instruments to capture the total benefits of agroforestry to both upland farmers and downstream communities.

Phase II MS4 challenges: moving toward effective stormwater management for small municipalities

Federal regulations for municipal separate storm sewer systems (MS4s) in the United States have been in place since 1990 as part of the Nation Pollutant Discharge Elimination System (NPDES), aiming to reduce sediment and pollutant loads originating from urban areas. However, small-municipality (Phase II) MS4s frequently grapple with several challenges, resulting in a lack of stakeholder buy-in and actionable stormwater management plans. We identify five common challenges concerning MS4 requirements based on literature review, professional experience, and feedback solicited from stakeholders, municipal managers, and fellow professionals and offer real-world examples of efficient, effective MS4 frameworks and/or solutions. The five challenges are summarized as beliefs that: (1) agricultural land use is the largest pollutant contributor and the root cause of pollution problems; (2) stormwater management only benefits downstream communities; (3) large, expensive projects are required to comply with regulations; (4) maintenance, monitoring, and inspection of best management practices (BMPs) is overwhelmingly complex and expensive; and (5) a lack of direct funding makes complying with regulations an impossible task. These challenges are universal in nature for Phase II MS4 permittees and can create real barriers for effective stormwater management. However, we found many examples of methods or techniques to effectively address these five specific challenges, making them well-suited and important for discussion. BMPs can create tangible improvements for surrounding communities (e.g., reduced streambank erosion and flooding), and improved understanding of the structure and options within the MS4 program will help small municipalities make informed choices about management plans.

A Tale of Three Himalayan Towns: Would Payment for Ecosystem Services Make Drinking Water Supply Sustainable?

The Himalayas are the source of freshwater to about one-fourth of the world’s population. Paradoxically, water scarcity is one of the most prominent climate crises in the Himalayan region in general and its cities in particular. Rapid urbanization coupled with climate change is causing the rapid disappearance of natural springs resulting in water shortage in the urban areas. Governments are investing in new water supply projects to fulfil the demand of city residents as existing water sources are drying up. Solely focussed on establishing the physical infrastructure to supply water from source to users, and these drinking water projects have by and large failed to protect the water sources. These projects rely on the assumption of a fixed quantum and quality of the water source not taking into account the impacts of changes in climate and the activities of upstream communities on the ecosystem. For sustainability of the drinking water supply, it is necessary to have subsidiary plans that bring together the upstream water source communities (service providers), downstream communities (service users) and the local authority. Incentive paymentfor ecosystem services is a strategy to incentivize upstream non-user or low-user communities, whose role is critical in maintaining and improving the water supply and preserving the watershed area. This chapter highlights practical aspects of the design and implementation of incentive payment schemes drawing on research from three case studies from three small Himalayan towns in Nepal.

Climate and energy justice along the Brahmaputra river in Northeast India

Recurrent summer floods along the Brahmaputra river and its tributaries are a major challenge for the people and state governments of Northeast India. While riverine communities in the region rely upon a variety of adaptation strategies to live with these destructive floods, climate change is expected to further exacerbate this challenge, as melting Himalayan glaciers and changes in the South Asian monsoon lead to an increase in the frequency of severe floods. At the same time, a multitude of new dams are under construction in the Brahmaputra river basin, to meet India’s growing energy demands. Though these dams could provide flood protection for downstream communities, political and economic factors have led dam-builders to prioritize hydroelectricity generation over flood control. Furthermore, hydroelectricity generated along the Brahmaputra is “evacuated” to distant urban centers, while rural dwellers in Northeast India suffer from high levels of energy poverty. Using the Ranganadi Hydroelectric Project in Arunachal Pradesh as a case study, this paper examines how, by changing the flood regime and undermining current adaptive strategies, large dams along the Brahmaputra are testing the capacity of downstream communities to live with summer floods. This work highlights the ways in which poor and vulnerable communities in Northeast India are forced to bear the costs of both climate change impacts and decarbonization efforts.

Natural Infrastructure Practices as Potential Flood Storage and Reduction for Farms and Rural Communities in the North Carolina Coastal Plain

Increased global temperatures resulting from anthropogenically induced climate changes have increased the frequency and severity of adverse weather events, including extreme rainfall events, floods, and droughts. In recent years, nature-based solutions (NBS) have been proposed to retain storm runoff temporarily and mitigate flood damages. These practices may help rural farm and forest lands to store runoff and reduce flooding on farms and downstream communities and could be incorporated into a conservation program to provide payments for these efforts, which would supplement traditional farm incomes. Despite their potential, there have been very few methodical assessments and detailed summaries of NBS to date. We identified and summarized potential flood reduction practices for the Coastal Plain of North Carolina. These include agricultural practices of (1) cover cropping/no-till farming; (2) hardpan breakup; (3) pine or (4) hardwood afforestation, and (5) agroforestry; establishing the wetland and stream practices of (6) grass and sedge wetlands and earthen retention structures, (7) forest wetland banks, and (8) stream channel restoration; and establishing new structural solutions of (9) dry dams and berms (water farming) and (10) tile drainage and water retention. These practices offer different water holding and storage capacities and costs. A mixture of practices at the farm and landscape level can be implemented for floodwater retention and attenuation and damage reduction, as well as for providing additional farm and forest ecosystem services.

Glacial lake outburst flood hazard under current and future conditions: first insights from a transboundary Himalayan basin

Glacial lake outburst floods (GLOFs) are a major concern throughout High Mountain Asia, where impacts can be far-reaching. This is particularly true for transboundary Himalayan basins, where risks are expected to further increase as new lakes develop. Given the need for anticipatory approaches to disaster risk reduction, this study aims to demonstrate how the threat from a future lake can be feasibly assessed along-side that of current lakes, and how this information can feed practically into decision-making and response planning. We have focused on two well-known dangerous lakes (Galongco and Jialongco), comparing the consequences of simulated worst-case outburst events from these lakes both in the Tibetan town of Nyalam and downstream at the border with Nepal. In addition, a future scenario has been assessed, whereby an outburst was simulated for a potential new lake forming upstream of Nyalam. Results show that although smallest in size, Jialongco, poses the greatest immediate threat to Nyalam and downstream communities, owing to the high potential for an ice avalanche to trigger an outburst. The future lake scenario would lead to flow depths and velocities that exceed either of the current scenarios, and the peak flood would reach Nepal up to 20 minutes faster. Based on these findings, a comprehensive approach to disaster risk reduction is called for, combining early warning systems with effective land use zoning and capacity building programs. Such approaches address the current drivers of GLOF risk in the basin, while remaining robust in the face of future emerging threats.

A Pilot Experiment on Infrasonic Lahar Detection at Mount Adams, Cascades: Ambient Infrasound and Wind-Noise Characterization at a Quiescent Stratovolcano

Erosion, hydrothermal activity, and magmatism at volcanoes can cause large and unexpected mass wasting events. Large fluidized debris flows have occurred within the past 6000 yr at Mount Adams, Washington, and present a hazard to communities downstream. In August 2017, we began a pilot experiment to investigate the potential of infrasound arrays for detecting and tracking debris flows at Mount Adams. We deployed a telemetered four-element infrasound array (BEAR, 85 m aperture), ~11 km from a geologically unstable area where mass wasting has repeatedly originated. We present a preliminary analysis of BEAR data, representing a survey of the ambient infrasound and noise environment at this quiescent stratovolcano. Array processing reveals near continuous and persistent infrasound signals arriving from the direction of Mount Adams, which we hypothesize are fluvial sounds from the steep drainages on the southwest flank. We interpret observed fluctuations in the detectability of these signals as resulting from a combination of (1) wind-noise variations at the array, (2) changes in local infrasound propagation conditions associated with atmospheric boundary layer variability, and (3) changing water flow speeds and volumes in the channels due to freezing, thawing, and precipitation events. Suspected mass movement events during the study period are small (volumes &lt;105 m3 and durations &lt;2 min), with one of five visually confirmed events detected infrasonically at BEAR. We locate this small event, which satellite imagery suggests was a glacial avalanche, using three additional temporary arrays operating for five days in August 2018. Events large enough to threaten downstream communities would likely produce stronger infrasonic signals detectable at BEAR. In complement to recent literature demonstrating the potential for infrasonic detection of volcano mass movements (Allstadt et al., 2018), this study highlights the practical and computational challenges involved in identifying signals of interest in the expected noisy background environment of volcanic topography and drainages.