Exit here: Strategies for dealing with aging dams and reservoirs

Aquatic Sciences (Springer) | October 22nd, 2019

Aging infrastructure is prevalent throughout the world, but water control management structures, specifically dams, are of growing concern. Dams and their corresponding r

Aging infrastructure is prevalent throughout the world, but water control management structures, specifically dams, are of growing concern. Dams and their corresponding reservoirs have inherent, but separate, lifespans. The proportion of dams around the world that continue operation beyond their intended lifespans is growing at an alarming rate. Society will not only have to navigate the tradeoffs associated with the deterioration of services provided by reservoirs and dams, but also impending structural failures. Society is nearing a critical pinch point where we will have to decide how to deal with dams and reservoirs at scales that range from a single system to multiple systems in large watersheds. No comprehensive strategy exists to inform both the range of actions that can be applied to such infrastructure and how such actions would influence biophysical, socioeconomic, and geopolitical tradeoffs. The development of proactive exit strategies is a critical first step in ensuring controlled transitions for aging dams and reservoirs. Herein, we present an overview of actions and considerations for aging dams and reservoirs, followed by an initial framework for exit strategy development to launch a further discussion on how society could deal with this aging infrastructure.

Final Value Planning Study Report for Through Delta Facility, Sacramento, California

California Department of Water Resources (DWR) | July 1st, 2007

Finishing the All-American Canal

Scientific American | September 1st, 2020

Work on the All-American Canal is going forward so rapidly that the great 80-mile ditch and its appurtenant features will be ready to de­liver irrigation water to the Im

Work on the All-American Canal is going forward so rapidly that the great 80-mile ditch and its appurtenant features will be ready to de­liver irrigation water to the Imperial Valley in southeastern California some time during the first half of 1938. The waterway is being dug across a normally desert region that once formed the wa­ter bed of the prehistoric northern ex­tension of the Gulf of California, as we know it today. Paradoxically, that far­ flung section of the Gulf was transform­ ed into a generally barren and arid region by the very river that is to be tapped to assure the continued agricul­tural productivity · of soil that can be made amazingly fruitful by irrigation.

Flood Risk and Management of California's Sacramento-San Joaquin Delta Levee System

University of California, Santa Cruz (UC Santa Cruz) | September 15th, 2020

Flood Size Increases Nonlinearly Across the Western United States in Response to Lower Snow-Precipitation Ratios

American Geophysical Union (AGU) | December 20th, 2019

Many mountainous and high-latitude regions have experienced more precipitation as rain rather than snow due to warmer winter temperatures. Further decreases in the annual

Many mountainous and high-latitude regions have experienced more precipitation as rain rather than snow due to warmer winter temperatures. Further decreases in the annual snow fraction are projected under continued global warming, with potential impacts on flood risk. Here, we quantify the size of streamflow peaks in response to both seasonal and event-specific rain-fraction using stream gage observations from watersheds across the western United States. Across the study watersheds, the largest rainfall-driven streamflow peaks are >2.5 times the size of the largest snowmelt-driven peaks. Using a panel regression analysis of individual precipitation and snowmelt events, we show that the empirical streamflow response grows approximately exponentially as the liquid precipitation input increases, with rain-dominated runoff leading to proportionately larger streamflow increases than snowmelt or mixed rain-and-snow runoff. We find that the response to changes in rain percentage is largest in the wettest watersheds, where wet antecedent conditions are important for increasing runoff efficiency. Similarly, the effect of rain percentage is larger across watersheds in the Northwest and West regions compared to watersheds in the Northern Rockies and Southwest regions. Overall, as a higher percentage of precipitation falls as rain, increases in the size of rainfall-driven and “rain-on-snow”-driven floods have the potential to more than offset decreases in the size of snowmelt-driven floods.

Flood-Risk Reduction and Resilience: Federal Assistance and Programs

Congressional Research Service (CRS) | November 15th, 2017

Recent flood disasters have raised congressional and public interest in not only reducing flood risks, but also improving flood resilience, which is the ability to adapt

Recent flood disasters have raised congressional and public interest in not only reducing flood risks, but also improving flood resilience, which is the ability to adapt to, withstand, and rapidly recover from floods. In the United States, flood-related responsibilities are shared. States and local governments have significant discretion in land-use and development decisions, which can be major factors in determining the vulnerability to and consequence of hurricanes, storms, extreme rainfall, and other flood events. Congress has established various federal programs that may be available to assist U.S. state, local, and territorial entities and tribes in reducing flood risks. Among the most significant federal activities to reduce communities’ flood risks and improve flood resilience are: assistance with infrastructure projects (e.g., levees, shore protection) and other flood mitigation activities that save lives and reduce property damage; and mitigation incentives for communities that participate in the National Flood Insurance Program (NFIP). This report provides an overview of these assistance programs and the NFIP-related mitigation incentives; it also raises flood-related policy considerations associated with federal programs and practices.

Formation and prevention of pipe scale from acid mine drainage at iron Mountain and Leviathan Mines, California, USA

Applied Geochemistry (Elsevier) | April 1st, 2020

Pipelines carrying acid mine drainage (AMD) to treatment plants commonly form pipe scale, an Fe(III)-rich precipitate that forms inside the pipelines and requires periodi

Pipelines carrying acid mine drainage (AMD) to treatment plants commonly form pipe scale, an Fe(III)-rich precipitate that forms inside the pipelines and requires periodic and costly cleanout and maintenance. Pipelines at Iron Mountain Mine (IMM) and Leviathan Mine (LM) in California carry acidic water from mine sources to a treatment plant and have developed pipe scale. Samples of scale and AMD were collected from both mine sites for mineralogical, microbiological, and chemical analysis. The scale mineralogy was primarily schwertmannite with minor amounts of poorly crystalline goethite. Although the bulk composition of the scale was similar along the length of the pipeline at IMM, the number of iron-oxidizing bacteria and concentrations of associated trace elements decreased along the flow path inside the pipeline. Laboratory batch experiments with unfiltered AMD from IMM and LM showed that Fe(II) oxidation was driven by microbial activity when the pH was <5. A remediation strategy of decreasing the pH to <2.2 was tested through geochemical modeling and laboratory experiments. These experiments indicated that scale formation could be prevented by decreasing the pH, which could be achieved at IMM by mixing source waters. However, the presence of Fe(III)-rich scale in a pipeline buffers the pH to higher values that may affect the efficacy of this remedial approach.

Fracturing dams, fractured data: Empirical trends and characteristics of existing and removed dams in the United States

River Research and Applications (Wiley) | May 20th, 2018

Dam removals in the United States continue to accelerate in pace and scope, but no national analyses have examined how removed dams compare with existing dam stock. Here,

Dam removals in the United States continue to accelerate in pace and scope, but no national analyses have examined how removed dams compare with existing dam stock. Here, we review and analyse the best available national data on dams from the National Inventory of Dams (NID), dam removals from American Rivers, the U.S. Geological Survey, and the National River Restoration Science Synthesis databases to compare trends and characteristics of removed versus existing dams in the United States. If historical trends continue, by 2050 the United States can expect between 4,000 and 36,000 total removals, including 2,000–10,000 removals of NID dams. Best‐fit regression models estimate total costs between $50.5 million and $25.1 billion (mean $10.5 billion, median $416.5 million) for all removals and $29.6 million to $18.9 billion (mean $7.2 billion, median $285 million) for NID removals, a significant cost savings over present stated dam rehabilitation needs. Structural characteristics and ages of documented removals are not representative of existing dams, with privately owned hydroelectric dams subject to public oversight and water supply dams the most disproportionately removed. We conclude that dam removal science would benefit from the creation of an interdisciplinary framework for studying dams as environmental, social, and technological interventions, facilitated by transparent datasets around dams and removals and reflexive research approaches that combine statistical approaches with place‐based analyses.

Fragmented Flows: Water Supply in Los Angeles County

Environmental Management (Springer) | May 12th, 2016

In the Los Angeles metropolitan region, nearly 100 public and private entities are formally involved in the management and distribution of potable water—a legacy rooted

In the Los Angeles metropolitan region, nearly 100 public and private entities are formally involved in the management and distribution of potable water—a legacy rooted in fragmented urban growth in the area and late 19th century convictions about local control of services. Yet, while policy debates focus on new forms of infrastructure, restructured pricing mechanisms, and other technical fixes, the complex institutional architecture of the present system has received little attention. In this paper, we trace the development of this system, describe its interconnections and disjunctures, and demonstrate the invisibility of water infrastructure in LA in multiple ways—through mapping, statistical analysis, and historical texts. Perverse blessings of past water abundance led to a complex, but less than resilient, system with users accustomed to cheap, easily accessible water. We describe the lack of transparency and accountability in the current system, as well as its shortcomings in building needed new infrastructure and instituting new water rate structures. Adapting to increasing water scarcity and likely droughts must include addressing the architecture of water management.

Friends of the Earth v. Coleman

United States Court of Appeals, Ninth Circuit | March 10th, 1975