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Map of the Pacific Northwest including the Columbia River basin and Coastal Drainages in WA and OR. Major dams in the Columbia and selected projects and geographic features discussed in the text are shown.
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Climate change impacts in Pacific Northwest Region of North America (PNW) are projected to include increasing temperatures and changes in the seasonality of precipitation (increasing precipitation in winter, decreasing precipitation in summer). Changes in precipitation are also spatially varying, with the northwestern parts of the region generally...
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... Yet nearly a generation after its passage, the WSRA remains relatively unstudied in terms of how managers interpret and implement its provisions as part of larger resource management, especially in comparison to other preservation-era legislation such as the Wilderness Act (Chesterton & Watson, 2017;Perry, 2017a;Bowker & Bergstrom, 2017). Much has changed in the management of public lands since 1968, including reductions in budgets for agencies managing public lands, shifts in societal values or public infrastructure needs, expansion or new roles for public involvement in collaborative management of protected areas, and a focus on landscape-level management priorities, including the impact of climate change (Clarke & McCool, 1996;Feldman et al., 2005;Daniels & Walker, 2001;Lurie & Hibbard, 2008;Hamlet, 2011;Archie et al., 2012;Weber & Stevenson, 2017). Understanding how the influences above continue to affect resource management surrounding Wild and Scenic Rivers (WSRs), and how agency professionals are responding to such challenges, are important mechanisms for adapting management to new realities while meeting the policy requirements of the WSRA. ...
The Wild and Scenic Rivers Act (WSRA) provides a high level of protection for free flowing rivers in the United States. Yet more than 50 years after its passage, there is little research exploring management of resources under the Act, including across agencies or private partners managing protected rivers. The research presented here used a mixed-method approach consisting of quantitative rankings and interviews to explore river manager and partner perspectives about the most pressing management actions and barriers for continued river management under the WSRA in concert with the 50th anniversary of the Act. We also explore the role of public-private partnerships in continued management of protected rivers. Our approach consisted of a national sample and replicates a similar effort conducted in concert with the 30th anniversary of the WSRA, providing a unique longitudinal perspective. Results indicate that a continued lack of public understanding or support for Wild and Scenic Rivers (WSRs), a need for dedicated agency funds to manage rivers once designated, and additional guidance about flexibly interpreting WSRA provisions as highly prioritized barriers or future actions. Qualitative results illuminate the importance of public partnerships in garnering political support for additional WSR management resources, key needs for manager exchanges or mentorship programs given the retirement of experienced WSR professionals, and the importance of organized, but varied private partnerships in planning or management of rivers across different regions of the United States. We conclude by discussing next steps for systematically gauging appreciation for WSRs among segments of the public, expanding understandings of the unique benefits associated with WSR designation, and further development of agency-public partnership templates surrounding designated river management.
... Climate modeling, regional variation, and armed conflict Climate modeling forecasts dramatic regional variation in temperature and precipitation anomalies as a result of changing pressures on weather systems (Hamlet 2011;Hansen et al. 2012;IPCC 2014;US DoD 2011). Within geographically expansive countries, the variation is expected to be large (Hamlet 2011). ...
... Climate modeling, regional variation, and armed conflict Climate modeling forecasts dramatic regional variation in temperature and precipitation anomalies as a result of changing pressures on weather systems (Hamlet 2011;Hansen et al. 2012;IPCC 2014;US DoD 2011). Within geographically expansive countries, the variation is expected to be large (Hamlet 2011). For example, on the African continent, a 2.5°square grid generates 42 separate grids incorporating the Democratic Republic of Congo, with each grid comprising a land area of approximately 270 by 270 km; there are 495 grids on the African continent. ...
The dynamic relationships between climate change and armed conflict have been discussed at length, but there have been few studies that integrate dimensions of climate adaptation into the processes linking climate change to armed conflict. By using geospatial grids for climate change and armed conflict, and country-level climate vulnerability measures of sensitivity and adaptive capacity, we empirically examine the effects of climatic and non-climatic conditions on the probability of armed conflict in Africa. Results suggest that there are close links between climate drivers and armed conflict. Importantly, greater levels of adaptive capacity lead to a lower likelihood of armed conflict. From a policy perspective, our results suggest that enhancing adaptive capacity under conditions of climate pressure will reduce the probability of people taking up arms in response to water scarcity.
... Opinions vary about whether large water management systems will be able to accommodate such changes. Some argue that the use of historical records as the basis for planning, combined with rigid reservoir operating rules, limits adaptation to changing conditions (Hamlet, 2011). Uncertainty surrounding the drivers of change complicates efforts to predict and manage under traditional approaches that assume stationarity (Cosens & Williams, 2012;Milly et al., 2008). ...
Around the world, long‐term changes in the timing and magnitude of streamflow are testing the ability of large managed water resource systems constructed in the 20th century to continue to meet objectives in the 21st century. Streamflow records for unregulated rivers upstream of reservoirs can be combined with records downstream of reservoirs using a paired‐watershed framework and concepts of water resource system performance to assess how reservoir management has responded to long‐term change. Using publicly available data, this study quantified how the intra‐annual timing of inflows and outflows of 25 major reservoirs has shifted, how management has responded, and how this has influenced reliability and vulnerability of the water resource system in the 668,000 km² Columbia River basin from 1950 to 2012. Reservoir inflows increased slightly in early spring and declined in late spring to early fall, but reservoir outflows increased in late summer from 1950 to 2012. Average inflows to reservoirs in the low flow period exceeded outflows in the1950s, but inflows are now less than outflows. Reservoirs have increased hedging, that is, they have stored more water during the spring, in order to meet the widening gap between inflows and outflows during the summer low flow period. For a given level of reliability (the fraction of time flow targets were met), vulnerability (the maximum departure from the flow target) was greater during periods with lower than average inflows. Thus, the water management system in this large river basin has adjusted to multi‐decade trends of declining inflows, but vulnerability, that is, the potential for excess releases in spring and shortfalls in summer, has increased. This study demonstrates the value of combining publicly available historical data on streamflow with concepts from paired‐watershed analyses and metrics of water resource performance to detect, evaluate, and manage water resource systems in large river basins.
... Similarly, simulations of reservoir operations for three future periods in Colorado River Basin projected a decrease in the probability of meeting demand from 92% in a historical climate simulation to 59-75% for future simulations (Christensen et al. 2004). In some locations, modified reservoir release policies have been developed to mitigate the impact of hydrologic shifts caused by climate change (Hamlet 2011 in Pacific Northwest Region of North America; Stagge et al. 2017 in Washington, DC). However, another study found that using reservoir balance models developed for a reservoir in Italy, climate change scenarios did not significantly affect the reservoir resilience (Mereu et al. 2016). ...
Climate change has the potential to alter the quantity and timing of runoff, which may pose significant challenges for reservoir management. One challenge is developing operating policies for an unknown and uncertain future. Here, we develop a suite of ‘optimal’ operating policies for the reservoir system of Portland, Oregon. We assess the sensitivity of projected reservoir reliability to the choice of GCMs and time periods used to develop each of our policies. Results indicate that, while different GCMs and fitting periods produce different optimal operating policies, when those policies are applied across all the other GCM scenarios, the overall projected reliability does not change due to the great variability between simulations. Across the simulations, we note a trend of decreasing reliability in the future which is not sensitive to the choice of GCM or fitting period. This indicates that the projected reliability is dominated by uncertainty in climate projections that cannot be mitigated by tuning operating policies to projected changes.
... Many coupled human-environment systems in Idaho centered on issues of water resources are being impacted by population growth, land-use change, and climate change. Idaho has been among the fastest growing states in the past decade (Sheridan, 2007;Smutny, 2002;Travis, 2007), relies heavily on snowmelt runoff for agricultural productivity and energy production (Hamlet and Lettenmaier, 1999;Hamlet, 2011), and has seen substantial declines in spring snowpack over the past century (e.g., Mote et al., 2005Mote et al., , 2018. Continued changes in these drivers of state-level water resources in the coming half-century are reasoned to impact Idaho's waterscapes (Tohver et al., 2014). ...
Water availability and use are increasingly critical factors determining the resilience and vulnerability of communities in the Western United States (US). Historical water availability and use in the state of Idaho is synthesized by considering the biophysical drivers of climate and surface runoff alongside human drivers of land-use, hydrologic engineering and state water management and policies. Idaho has not experienced chronic water scarcity in the last half century, particularly in comparison to neighboring states to the south. An outlook of water availability and use in Idaho for the next half century is developed that accounts for projected changes in population and climate. The magnitude of annual runoff is not expected to change substantially across much of Idaho, yet the timing of surface water availability is likely to change due to earlier snowmelt and reduced summer surface water availability. We posit that Idaho is well positioned to make institutional and policy decisions that secure its own water resources in the face of changing environmental conditions and resource-based water demands.
... The basin has frequent fluvial flooding, with overtopping expected to happen every 2 to 5 years [50]. The Snohomish River Basin belongs to the U.S. Pacific Northwest region, which was projected to experience the temporal and spatial changes in precipitation, with possible shifts of high (for example, flood) and low flow extremes [51]. ...
Flooding is a prevalent natural disaster with both short and long-term social, economic, and infrastructure impacts. Changes in intensity and frequency of precipitation (including rain, snow, and rain-on-snow) events create challenges for the planning and management of resilient infrastructure and communities. While there is general acknowledgment that new infrastructure design should account for future climate change, no clear methods or actionable information are available to community planners and designers to ensure resilient designs considering an uncertain climate future. This research demonstrates an approach for an integrated, multi-model, and multi-scale simulation to evaluate future flood impacts. This research used regional climate projections to drive high-resolution hydrology and flood models to evaluate social, economic, and infrastructure resilience for the Snohomish Watershed, WA, USA. Using the proposed integrated modeling approach, the peaks of precipitation and streamflows were found to shift from spring and summer to the earlier winter season. Moreover, clear non-stationarities in future flood risk were discovered under various climate scenarios. This research provides a clear approach for the incorporation of climate science in flood resilience analysis and to also provides actionable information relative to the frequency and intensity of future precipitation events.
... Precipitation in the region occurs predominantly from October to March and falls as snow or rain, depending mainly on elevation and proximity to the Pacific Ocean. Snowmelt contributes to stream flow from April to September in snowmelt-dominated and transitional watersheds (Hamlet 2010). Human population density in the study area ranged from low (e.g., roadless areas in Idaho) to high (e.g., near major cities). ...
Climate-change driven increases in water temperature pose challenges for aquatic organisms. Predictions of impacts typically do not account for fine-grained spatiotemporal thermal patterns in rivers. Patches of cooler water could serve as refuges for anadromous species like salmon that migrate during summer. We used high-resolution remotely sensed water temperature data to characterize summer thermal heterogeneity patterns for 11,308 km of second–seventh-order rivers throughout the Pacific Northwest and northern California (USA). We evaluated (1) water temperature patterns at different spatial resolutions, (2) the frequency, size, and spacing of cool thermal patches suitable for Pacific salmon (i.e., contiguous stretches ≥ 0.25 km, ≤ 15 °C and ≥ 2 °C, aooler than adjacent water), and (3) potential influences of climate change on availability of cool patches. Thermal heterogeneity was nonlinearly related to the spatial resolution of water temperature data, and heterogeneity at fine resolution (< 1 km) would have been difficult to quantify without spatially continuous data. Cool patches were generally > 2.7 and < 13.0 km long, and spacing among patches was generally > 5.7 and < 49.4 km. Thermal heterogeneity varied among rivers, some of which had long uninterrupted stretches of warm water ≥ 20 °C, and others had many smaller cool patches. Our models predicted little change in future thermal heterogeneity among rivers, but within-river patterns sometimes changed markedly compared to contemporary patterns. These results can inform long-term monitoring programs as well as near-term climate-adaptation strategies.
... SWE/P substantially decreases with each time period, indicating a hydrologic regime shift from a snow-rain-dominated to a rain-dominated basin. This is consistent with predictions in the Pacific Northwest [5,14,[64][65][66][67][68]. Vynee et al. [65] predicted SWE to decrease more than 50% by the 2080s in the URB. ...
This study analyzed watershed response to climate change and forest fire impacts in the upper Umatilla River Basin (URB), Oregon, using the precipitation runoff modeling system. Ten global climate models using Coupled Intercomparison Project Phase 5 experiments with Representative Concentration Pathways (RCP) 4.5 and 8.5 were used to simulate the effects of climate and fire-burns on runoff behavior throughout the 21st century. We observed the center timing (CT) of flow, seasonal flows, snow water equivalent (SWE) and basin recharge. In the upper URB, hydrologic regime shifts from a snow-rain-dominated to rain-dominated basin. Ensemble mean CT occurs 27 days earlier in RCP 4.5 and 33 days earlier in RCP 8.5, in comparison to historic conditions (1980s) by the end of the 21st century. After forest cover reduction in the 2080s, CT occurs 35 days earlier in RCP 4.5 and 29 days earlier in RCP 8.5. The difference in mean CT after fire-burns may be due to projected changes in the individual climate model. Winter flow is projected to decline after forest cover reduction in the 2080s by 85% and 72% in RCP 4.5 and RCP 8.5, in comparison to 98% change in ensemble mean winter flows in the 2080s before forest cover reduction. The ratio of ensemble mean snow water equivalent to precipitation substantially decreases by 81% and 91% in the 2050s and 2080s before forest cover reduction and a decrease of 90% in RCP 4.5 and 99% in RCP 8.5 in the 2080s after fire-burns. Mean basin recharge is 10% and 14% lower in the 2080s before fire-burns and after fire-burns, and it decreases by 13% in RCP 4.5 and decreases 22% in RCP 8.5 in the 2080s in comparison to historical conditions. Mixed results for recharge after forest cover reduction suggest that an increase may be due to the size of burned areas, decreased canopy interception and less evaporation occurring at the watershed surface, increasing the potential for infiltration. The effects of fire on the watershed system are strongly indicated by a significant increase in winter seasonal flows and a slight reduction in summer flows. Findings from this study may improve adaptive management of water resources, flood control and the effects of fire on a watershed system.
... Understanding how relationships between snowpack, precipitation , and temperature will be expressed at the basin scale is particularly important in the maritime PNW. Physically based modeling studies of climate impacts in the PNW describe reduced snow water storage and earlier streamflow across the region (Elsner et al., 2010; Hamlet, 2011; Sproles et al., 2013). These deterministic approaches provide a range of outputs of past and future conditions. ...
In the Pacific Northwest, USA, the extraordinarily low snowpacks of winters 2013–2014 and 2014–2015 stressed regional water resources and the social-environmental system. We introduce two new approaches to better understand how seasonal snow water storage during these two winters would compare to snow water storage under warmer climate conditions. The first approach calculates a spatial-probabilistic metric representing the likelihood that the snow water storage of 2013–2014 and 2014–2015 would occur under +2 °C perturbed climate conditions. We computed snow water storage (basin-wide and across elevations) and the ratio of snow water equivalent to cumulative precipitation (across elevations) for the McKenzie River basin (3041 km²), a major tributary to the Willamette River in Oregon, USA. We applied these computations to calculate the occurrence probability for similarly low snow water storage under climate warming. Results suggest that, relative to +2 °C conditions, basin-wide snow water storage during winter 2013–2014 would be above average, while that of winter 2014–2015 would be far below average. Snow water storage on 1 April corresponds to a 42 % (2013–2014) and 92 % (2014–2015) probability of being met or exceeded in any given year. The second approach introduces the concept of snow analogs to improve the anticipatory capacity of climate change impacts on snow-derived water resources. The use of a spatial-probabilistic approach and snow analogs provide new methods of assessing basin-wide snow water storage in a non-stationary climate and are readily applicable in other snow-dominated watersheds.
... Barsugli ve ark. [5] ve Hamlet [6] tarafından belirtildiğine göre; son yıllarda, yerel ve bölgesel ölçekte yüzey iklimindeki tarihsel trendler oldukça dikkate değer bir konu olarak kabul edilmektedir ve iklim üzerinde oluşabilecek olumsuz değişimleri azaltmak için birçok strateji geliştirilmiştir. Tarihsel iklim üzerindeki küresel veya geleneksel ölçekteki gözlemler veya gelecekteki iklim projeksiyonları, yerel ve bölgesel ölçek planlamaları için daha az kullanışlıdır [5]. ...
Precipitation, temperature and streamflow parameters are the most important hydro-meteorological variables that reveal climate change/climate variability in the planning and management of water resources. Parametric and non-parametric trend tests are used to analyze long-term gradual changes or trends on hydro-meteorological variables. The Mann-Kendall test and Sen's slope estimation method are used as widely as from past to present and have shown very good performance in determining the trend for hydro-meteorological variables. The trend analysis for hydro-meteorological parameters will provide many benefits to water managers in better management and planning of water resources. In this study; informations on the most commonly used trend tests on hydro-meteorological variables was compiled, examples of trend analysis for different regions of the world were put forward, and a general evaluation was made on the importance of trend analysis in the direction of these examples. Özet Yağış, sıcaklık ve akış parametreleri, su kaynaklarının planlanmasında ve yönetiminde iklim değişimi/iklim değişkenliğini ortaya koyan en önemli hidro-meteorolojik değişkenlerdir. Hidro-meteorolojik değişkenler üzerinde uzun zamanlı kademeli değişimleri veya eğilimleri analiz etmek için parametrik ve parametrik olmayan trend testleri kullanılmaktadır. Hidro-meteorolojik değişkenler için trendin belirlenmesinde Mann-Kendall testi ve Sen'in eğim tahmini yöntemi geçmişten günümüze kadar çok yaygın olarak kullanılmakta ve çok iyi bir performans ortaya koymaktadır. Hidro-meteorolojik parametrelere ilişkin yapılacak olan trend analizi, su kaynaklarının daha iyi yönetimi ve planlanmasında su yöneticilerine birçok fayda sağlayacaktır. Bu çalışmada; hidro-meteorolojik değişkenler üzerinde en yaygın olarak kullanılan trend testlerine ilişkin bilgiler derlenmiş, dünyanın farklı bölgeleri için trend analizi örnekleri ortaya konulmuş ve bu örnekler doğrultusunda trend analizinin önemi konusunda genel bir değerlendirme yapılmıştır. Anahtar Kelimeler: İklim değişimi, yağış, sıcaklık, akış, trend analizi, Mann-Kendall testi 1. Giriş İklim değişimi, yıllar veya daha uzun periyodlar için var olan iklim ortalamalarındaki büyük değişimler olarak ifade edilmektedir. İklim değişimi küresel ölçekte oluşmasına rağmen, iklim değişiminin etkisi bölgeden bölgeye farklılık göstermektedir [1]. Bundan dolayı, iklim değişiminin izlenmesinde meteorolojik değişkenlerdeki değişimlerin analizi oldukça önemli bir konudur [2]. Özellikle bir bölge için mevcut ve geçmişteki hidro-meteorolojik değişkenlerin değişimleri ve trendlerin bilgisi, nüfus artışı ve ekonomik büyümeden dolayı suya olan gereksinimin artması ve küresel ısınma, su
