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Low-head dams can cause dangerous currents near the downstream face of the structure. Fatalities at low-head dams with such currents, often referred to as “drowning machines,” are poorly documented. This technical note presents a new database of fatalities at low-head dams in the United States together with an interactive map and web-based user int...
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... map is provided which allows users to zoom and click on a geographic location. Clicking on the map will automatically populate the latitude, longitude, city, county, and state fields as shown in Figure 5. If selecting a site that is already in the database, the user may select the site from a drop down menu or click the site marker on the map. ...
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Citations
... A relational geodatabase with the associated interactive map and the WebGIS user interface for the low-head dams has been developed in the United States. It raises awareness and informs the general public and administrators about these dangerous structures and the need to remedy the situation (Kern et al. 2015). ...
The use of instrumentation in monitoring or evaluating geodynamic phenomena such as landslide, ground subsidence, earthquake, as well as engineering structures such as dams, foundations, deep excavations, landfills, tunnels and underground openings is widespread. The data of common instruments including piezometers, load/pressure cells, settlement-meters, extensometers, inclinometers, tiltmeters, etc. accumulates over time and forms a huge volume which, without having a proper database and application, causes many problems for users. Therefore, it is essential to create a database/application to store and analyze such periodic datasets in an integrated environment. ArcGIS as a good geospatial platform was used to store, retrieve, analyze, and visualize the instrumentation data. Being one of the most complex types of projects in terms of spatial arrangement of instruments, the embankment dam was chosen, the data of which was used to develop a geodatabase/application. For the purposes of this paper, a relational geodatabase is designed based on data from instruments installed in a dam in NW Iran. Then, a new Dam Data Analysis Application (DDAA) Toolbox was developed using ArcGIS ModelBuilder. DDAA provides valuable custom maps/charts in cross and longitudinal sections of the dam for parameters of pore-pressure, pore-pressure ratio, total stress, arching ratio, and displacement. Also, the toolbox was carefully evaluated and a complete correlation of observations with model-driven results was obtained. It is emphasized that the main purpose of this paper is to develop a geodatabase/application to manage instrumentation data rather than to analyze the behavior of a specific structure.Graphical Abstract
... Submerged hydraulic jumps are responsible for more than a thousand fatalities at LHDs across the United States since 1950. Efforts have been made to create a low-head dam fatality database to raise awareness of their potential dangerous conditions [6]. ...
... Edward Kern [6] describes the importance of creating a national inventory of low-head dams to address standards and improve public safety. Similar to Kern [6], Januchowski-Hartley [7] describes the importance of documenting the location of instream obstructions to restore stream connectivity. LHDs are often overlooked by obstruction inventories because they do not have a hazard classification and because they are under 1.8 m high. ...
Identifying low-head dams (LHDs) and creating an inventory is a priority, as fatalities continue to occur at these structures. Because obstruction inventories do not specifically identify LHDs and they are not assigned a hazard classification, there is no official inventory of LHDs; a multi-agency taskforce is creating one now by identifying LHDs using Google Earth Pro (GE Pro). The purpose of this paper is to assess whether a machine learning approach can accelerate the creation of the national inventory. We implemented a machine learning approach to use a high-resolution remote sensing data with a Convolutional Neural Network (CNN) architecture. The model achieved 76% accuracy in identifying LHDs (true positives) and 95% accuracy identifying Non-low-head-dams (true negatives) on the validation set. We deployed the trained model for the National Hydrologic Geospatial Fabric (Hydrofabric) flowlines in the Provo River watershed. The results showed a high number of false positives and low accuracy due to the mismatch between Hydrofabric flowlines and actual waterways. We recommend improving the accuracies of the Hydrofabric waterway tracing algorithms to increase the percentage of correctly classified LHDs.
... A fatality database can be used as a list of dams that almost certainly create submerged hydraulic jumps. Brigham Young University maintains a national low head dam fatality database with 625 fatalities recorded at 315 different dams [16]. It is certainly incomplete, but it is the largest public database available. ...
... First, the fatality database is incomplete. According to experts, there are far more fatalities than those in the BYU database [1,16]. Second, even with a complete fatality record, submerged hydraulic jumps could occur at low head dams with no recorded fatalities. ...
With the increasing availability of low head dam inventories for the United States, the next challenge is discovering how to determine what dams pose the greatest risk to public safety, preferably before a death occurs. Submerged hydraulic jumps create the dangerous current that drowns roughly 50 recreationists each year, and high tailwater is a key element in its formation. Using a simplified approach based on the Manning equation, flat downstream slopes can be a predictor of high tailwater. Stream slopes at low head dams in Colorado, Idaho, Indiana, Maryland, New Mexico, North Carolina, and Pennsylvania were collected from the NHDPlus HR, and dams with recorded fatalities were compared to stream slopes at low head dams with no recorded fatalities. Using the Mann–Whitney U test, there was not enough evidence to reject the null hypothesis that there is no statistically significant difference between the two populations. Until more fatality data are compiled and more low head dam locations are verified, individual testing of dams is recommended to establish each respective flow range that is likely to pose a risk to public safety.
... Dam failure is not the only risk that outdated dams pose to human life and well-being. There have been 555 fatalities at 276 low-head dams throughout the United States since the 1950s (Kern et al. 2015), 19 of which occurred in Texas between 1995 and 2016 (Kern et al. 2015). Low-head dams generally result in fatalities when someone goes over top of the dam and becomes trapped in the submerged jump the dams create (Wright et al. 1995;Elverum and Smalley 2012;Kern et al. 2015). ...
... Dam failure is not the only risk that outdated dams pose to human life and well-being. There have been 555 fatalities at 276 low-head dams throughout the United States since the 1950s (Kern et al. 2015), 19 of which occurred in Texas between 1995 and 2016 (Kern et al. 2015). Low-head dams generally result in fatalities when someone goes over top of the dam and becomes trapped in the submerged jump the dams create (Wright et al. 1995;Elverum and Smalley 2012;Kern et al. 2015). ...
... There have been 555 fatalities at 276 low-head dams throughout the United States since the 1950s (Kern et al. 2015), 19 of which occurred in Texas between 1995 and 2016 (Kern et al. 2015). Low-head dams generally result in fatalities when someone goes over top of the dam and becomes trapped in the submerged jump the dams create (Wright et al. 1995;Elverum and Smalley 2012;Kern et al. 2015). River users are often unaware of the hazard these dams present (Tschantz and Wright 2011), and older structures may often go unregulated (Kern 2014). ...
This study examines spatial and temporal trends in Texas dams, dam failures, and dam removals. Dams were examined from a state-wide perspective and within 10 major river basins that collectively account for over 80% of all dams in the state. The state-scale and basin-scale analysis revealed similar patterns of dam occurrence, however there was greater variation in the patterns observed in both the purpose of dams and the timing for when most of the storage was created in each basin. Climate factors, mainly precipitation, influenced dam location. Population was not directly measured in this study but was an obvious influence on the spatial distribution of dams and their functions. While new dams are being built in Texas to secure future water supplies, documented dam incidents/failures have occurred in 15 of the 23 major river basins in Texas, with 328 total instances occurring since 1900. As the number of newly constructed dams and dam failures continue to grow across the state, so should the number of planned dam removals. Between 1983 and 2016, 50 dams have been removed across the state. The purpose for the majority of removals was to eliminate liability concerns associated with aging dams. Future dam removals will likely continue to occur based on the number of older, smaller dams with potential liability concerns. As Texas’ dam infrastructure continues to age, dam removal is a practical management option for mitigating potential dam-related hazards and improving the connectivity and ecological function of the river systems. Citation: Dascher ED, Meitzen K. 2020. Dams are coming down, but not always by choice: the geograph of Texas dams, dam failures, and dam removals. Texas Water Journal. 11(1):89-129. Available from: https://doi.org/10.21423/twj.v11i1.7092.
... Dam failure is not the only risk that outdated dams pose to human life and well-being. There have been 555 fatalities at 276 low-head dams throughout the United States since the 1950s (Kern et al. 2015), 19 of which occurred in Texas between 1995 and 2016 (Kern et al. 2015). Low-head dams generally result in fatalities when someone goes over top of the dam and becomes trapped in the submerged jump the dams create (Wright et al. 1995;Elverum and Smalley 2012;Kern et al. 2015). ...
... Dam failure is not the only risk that outdated dams pose to human life and well-being. There have been 555 fatalities at 276 low-head dams throughout the United States since the 1950s (Kern et al. 2015), 19 of which occurred in Texas between 1995 and 2016 (Kern et al. 2015). Low-head dams generally result in fatalities when someone goes over top of the dam and becomes trapped in the submerged jump the dams create (Wright et al. 1995;Elverum and Smalley 2012;Kern et al. 2015). ...
... There have been 555 fatalities at 276 low-head dams throughout the United States since the 1950s (Kern et al. 2015), 19 of which occurred in Texas between 1995 and 2016 (Kern et al. 2015). Low-head dams generally result in fatalities when someone goes over top of the dam and becomes trapped in the submerged jump the dams create (Wright et al. 1995;Elverum and Smalley 2012;Kern et al. 2015). River users are often unaware of the hazard these dams present (Tschantz and Wright 2011), and older structures may often go unregulated (Kern 2014). ...
This study examines spatial and temporal trends in Texas dams, dam failures, and dam removals. Dams were examined
from a statewide perspective and within 10 major river basins that collectively account for over 80% of all dams in the state. The
state-scale and basin-scale analyses revealed similar patterns of dam occurrence, but there was greater variation in the patterns
observed in both the purpose of dams and the timing for when most of the storage was created in each basin. Climate factors,
mainly precipitation, influenced dam location. Population was not directly measured in this study but was an obvious influence
on the spatial distribution of dams and their functions. While new dams are being built in Texas to secure future water supplies,
documented dam incidents/failures have occurred in 15 of the 23 major river basins in Texas, with 328 total instances occurring
since 1900. As the number of newly constructed dams and dam failures continue to grow across the state, so should the number
of planned dam removals. Between 1983 and 2016, 50 dams were removed across the state. The purpose for the majority of
removals was to eliminate liability concerns associated with aging dams. Future dam removals will likely continue to occur based
on the number of older, smaller dams with potential liability concerns. As Texas’ dam infrastructure continues to age, dam removal is a practical management option for mitigating potential dam-related hazards and improving the connectivity and ecological
function of river systems.
... Small dams can be modified to be safer for boaters (Schweiger et al., 2017) but there is no evidence that many dam owners actively make such modifications. Hotchkiss, Kern, and their colleagues at Brigham Young University assembled a GIS database entitled "Location of Killer Weirs" as part of an effort to put forth a "low-head dam fatality database" (Kern, Hotchkiss, & Ames, 2015, but this resource depends on incidents being reported from sites across the United States. ...
Most of the United States' 2.5 million dams are not under the jurisdiction of any public agency. These small (under 6 ft [1.83 m] tall) nonjurisdictional dams, unregulated and not inventoried anywhere, endanger public safety and degrade riparian ecosystems. Their problems are increasing as structures age and storm events become more violent. Property owners can be held liable for problems at dams. Through several policy changes and legal actions, states can vastly improve the situation. States should consider expanded jurisdiction over small dams, a program of inventorying and mapping all dams in state waterways, owner education and outreach, and shared resources to allow for improved public safety and river restoration through best dam management or dam removal practices.
This article is categorized under:
• Human Water > Water Governance
• Engineering Water > Planning Water
• Water and Life > Stresses and Pressures on Ecosystems
Abstract
This dam in LakeCounty, Montana stands 6 ft (1.83 m) tall.
... Des accidents mortels affectant des pratiquants du cano?-kayak lors du franchissement des ouvrages ponctuent ?galement l'actualit? estivale des ?tats ?tudi?s ( Tschantz et Wright, 2011 ;Tschantz, 2014 ;Kern et al., 2015). Ainsi, la plupart des ?tats disposent d'une l?gislation pr?cise quant ? ...
... Dams and other flow-control structures can have dramatic effects on lotic habitat by altering water chemistry and flow (Baxter 1977), river geomorphology (Ligon et al. 1995), fish and macroinvertebrate communities (Lessard and Hayes 2003;Santucci et al. 2005;Tiemann et al. 2004) and can cause a reduction of gene flow among populations, leading to reduced genetic diversity and increased genetic differentiation (Wofford et al. 2005;McCraney et al. 2010). Low-head dams (small drop structures in rivers, streams or channels constructed to impound water, meter discharge, or maintain stream slope; Kern et al. 2015) and weirs have been shown to influence gene flow and genetic diversity in some darter species (e.g., Haponski et al. 2007;Beneteau et al. 2009;Sterling et al. 2012). Low head dams (hereafter dams) in the Comal and San Marcos rivers impound water for recreational use and are a potential source of habitat fragmentation for fountain darters. ...
The endangered fountain darter Etheostoma fonticola is found only in the Comal and San Marcos rivers in the Guadalupe River basin in central Texas, USA. Comal River fountain darters were believed to be extirpated following a severe drought in the 1950s and were reintroduced in the early 1970s using 457 darters from the San Marcos River. In this study we used 23 microsatellite loci to describe and evaluate the genetic diversity, population structure and effective population size (N
e) of fountain darters. We also evaluated the genetic effect of the Comal River reintroduction and the influence of low-head dams (dams) on dispersal in both rivers. Bayesian analysis of individual genotypes and Analysis of Molecular Variation supported two distinct populations concordant with the two rivers. Estimates of N
e were much smaller (<10 %) than census size (N
c) in both rivers but did not indicate the populations are at risk of an immediate and rapid loss of genetic diversity. Coalescent-based estimates of the genetically effective number of founders (Nf) for the Comal River averaged about 49 darters and, together with the indices of genetic diversity and the bottleneck test (heterozygosity excess) results, were consistent with a founder event following the reintroduction in the Comal River. Finally, our results regarding the influence of dams on fountain darter dispersal were equivocal and did not support a conclusion. We recommend this issue be examined further as part of the fountain darter recovery program.
... A growing community of professionals is investigating portfolios of infrastructure that meet infrastructure needs such hydropower and water supply, while also minimizing environmental damage (Ziv et al., 2012), meeting local subsistence fishing and agricultural needs (Richter et al., 2010), and addressing recreational safety (e.g. Kern et al., 2015). ...
Water resources and transportation infrastructure such as dams and culverts provide countless socio-economic benefits; however, this infrastructure can also disconnect the movement of organisms, sediment, and water through river ecosystems. Trade-offs associated with these competing costs and benefits occur globally, with applications in barrier addition (e.g. dam and road construction), reengineering (e.g. culvert repair), and removal (e.g. dam removal and aging infrastructure). Barrier prioritization provides a unique opportunity to: (i) restore and reconnect potentially large habitat patches quickly and effectively and (ii) avoid impacts prior to occurrence in line with the mitigation hierarchy (i.e. avoid then minimize then mitigate). This paper synthesizes 46 watershed-scale barrier planning studies and presents a procedure to guide barrier prioritization associated with connectivity for aquatic organisms. We focus on practical issues informing prioritization studies such as available data sets, methods, techniques, and tools. We conclude with a discussion of emerging trends and issues in barrier prioritization and key opportunities for enhancing the body of knowledge. Copyright
Dams, road crossings, and water withdrawals extensively fragment rivers, and watersheds often contain hundreds or thousands of barriers, some of which no longer meet societal purposes. Accordingly, both conservationists and infrastructure managers are faced with the challenge of prioritizing barriers for repair, replacement, or removal. Candidate projects have been prioritized with dozens of methods, which span a wide range of spatial scales, data and analytical requirements, mathematical complexity, and capacity to reconcile multiple perspectives and objectives. We briefly review barrier prioritization methods from the perspective of a policy maker or manager who must balance realities of stochastic opportunities, conflicting priorities, and risk of infrastructure failure. After outlining common motivations for barrier prioritization, we present a menu of techniques ranging from large‐scale, quantitative assessments to reactive, local response to failures. By clarifying the appropriate domain for each approach, this review informs the selection of prioritization methods for restoring riverine connectivity.
