Valuing Urban Nature – Implications for Flood Resilience

Stanford University | June 3rd, 2019

Sea-level rise and extreme weather events such as torrential rain storms are having devastating consequences in the United States and globally. Researchers, prac

Sea-level rise and extreme weather events such as torrential rain storms are having devastating consequences in the United States and globally. Researchers, practitioners, and policymakers are increasingly calling for the use of natural and nature-based approaches to protect urban areas from flooding which has increased in frequency and intensity as a result. Natural features can help stabilize shorelines and protect communities from river flooding while, providing other co- benefits for people and ecosystems. In a new study, scientists at the Natural Capital Project developed a framework for valuating urban nature and examined different factors cities must consider when making infrastructure and other investment choices. This brief is part of a series based on that research which looks at nature’s abilityto provide resilience to flooding and the various co-benefits associated with nature-based solutions.

Warming weakens the night-time barrier to global fire

Nature Portfolio (Springer Nature) | February 16th, 2022

Night-time provides a critical window for slowing or extinguishing fires owing to the lower temperature and the lower vapour pressure deficit (VPD). However, fire danger

Night-time provides a critical window for slowing or extinguishing fires owing to the lower temperature and the lower vapour pressure deficit (VPD). However, fire danger is most often assessed based on daytime conditions1,2, capturing what promotes fire spread rather than what impedes fire. Although it is well appreciated that changing daytime weather conditions are exacerbating fire, potential changes in night-time conditions—and their associated role as fire reducers—are less understood. Here we show that night-time fire intensity has increased, which is linked to hotter and drier nights. Our findings are based on global satellite observations of daytime and night-time fire detections and corresponding hourly climate data, from which we determine landcover-specific thresholds of VPD (VPDt), below which fire detections are very rare (less than 95 per cent modelled chance). Globally, daily minimum VPD increased by 25 per cent from 1979 to 2020. Across burnable lands, the annual number of flammable night-time hours—when VPD exceeds VPDt—increased by 110 hours, allowing five additional nights when flammability never ceases. Across nearly one-fifth of burnable lands, flammable nights increased by at least one week across this period. Globally, night fires have become 7.2 per cent more intense from 2003 to 2020, measured via a satellite record. These results reinforce the lack of night-time relief that wildfire suppression teams have experienced in recent years. We expect that continued night-time warming owing to anthropogenic climate change will promote more intense, longer-lasting and larger fires.

Water and Suspended-Sediment Flux Measurements at the Golden Gate, 2016-2017

San Francisco Estuary Institute (SFEI) | December 1st, 2017

Sediment is an important resource for San Francisco Bay (SFB), in the context of restoration projects, dredging operations, ecosystem health, and contaminant transport an

Sediment is an important resource for San Francisco Bay (SFB), in the context of restoration projects, dredging operations, ecosystem health, and contaminant transport and fate. Understanding the transport and fate of sediment in SFB is important to ecosystem researchers and managers. Previous studies have shown that sediment exchange at the estuary-ocean boundary of SFB (Golden Gate inlet) is the most poorly understood element of the SFB sediment budget, owing to logistical challenges that inhibit routine field observations, and the fact that net flux is a small fraction of the instantaneous peak values experienced on a daily basis. Improved understanding of sediment exchange at the estuary-ocean boundary of SFB is essential to updating SFB-wide sediment budgets, which account for sources, sinks, and storage of sediment (and sediment-associated contaminants). In this study, field observations of water and suspended-sediment fluxes at the Golden Gate were made over one ebb tide and one flood tide on three occasions: 1) 21-22 March 2016, following a large storm event that triggered the first flow into Yolo Bypass flood control structure since 2011 2) 23 June of 2016, during a period of low freshwater inflow; 3) 27-28 February 2017, following several large storms of the wettest winter in northern California in recorded history.

Water Resources Data for California, Water year 1983, Volume 2, Pacific Slope Basins from Arroyo Grande to Oregon State Line except Central Valley

U.S. Geological Survey (USGS) | January 15th, 1985

Water resources data for the 1983 water year for California consists of records of stage, discharge, and water quality of streams; stage and contents in lakes and reservo

Water resources data for the 1983 water year for California consists of records of stage, discharge, and water quality of streams; stage and contents in lakes and reservoirs; and water levels and water quality in wells. Volume 2 contains discharge records for 145 gaging stations; stage and contents for 19 lakes and reservoirs; water quality for 17 stations; water levels for 67 observation wells. Also included are 2 low-flow partial-record stations and 18 water-quality partial-record stations. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating State and Federal agencies in California.

Water Wasted to the Sea?

University of California, Davis (UC Davis) | July 15th, 2017

Watershed Modeling for the Santa Clara River in Southern California

Ventura County Public Works Agency (VCPWA) | July 24th, 2019

A calibrated watershed hydrologic model of the Santa Clara River (SCR) Watershed was developed for use as a tool for watershed planning, resource assessment, and ultima

A calibrated watershed hydrologic model of the Santa Clara River (SCR) Watershed was developed for use as a tool for watershed planning, resource assessment, and ultimately, water quality management purposes. The study was a joint effort of the Ventura County Watershed Protection District (VCWPD), Los Angeles County Department of Public Works (LACDPW), and U.S. Army Corp of Engineers Los Angeles District. The modeling package used for the study was the U.S. EPA Hydrologic Simulation Program – FORTRAN (HSPF). The SCR main stem flows east-to-west from the San Gabriel Mountains of central Los Angeles County to its mouth at the Pacific Ocean near the cities of Ventura and Oxnard. The 4,263 square kilometer watershed includes rapidly urbanizing valleys and extensive agriculture, and is subject to severe flooding and erosion. There are four large reservoirs within the watershed. Although the Santa Clara River watershed remains primarily in a natural physical state, the flow regime within the watershed is highly engineered to optimize water deliveries and aquifer recharge. The SCR Watershed was segmented into 209 subwatersheds and 192 stream reaches, based on precipitation patterns, drainage boundaries, hydrography, stream gage locations, and impaired water segments. Each land segment was further subdivided into individual model segments based on land use/cover categories. A long-term data base of 46 years of model input data (precipitation, evaporation, diversions, POTWs, etc.) was developed. The model was calibrated and validated to observed flow at multiple locations, using both graphical and statistical model-data comparisons. Long-term simulations were run to assess the impacts of alternative conditions (baseline, natural) on flow and flood frequencies. The model was also used to generate design storm event hydrographs for selected return intervals with synthetic input rainfall hyetographs for the corresponding rainfall return period developed from available rain gage data. The design storm results were submitted to FEMA for the Flood Insurance Study currently underway.

What Threat Does Sea-Level Rise Pose to California?

Legislative Analyst's Office (LAO) | August 10th, 2020

Among Its Other Challenges, California Continues to Face the Looming Impacts of Climate Change and Rising Seas. While the coronavirus disease 2019 (COVID‑19) pandemic a

Among Its Other Challenges, California Continues to Face the Looming Impacts of Climate Change and Rising Seas. While the coronavirus disease 2019 (COVID‑19) pandemic and resulting economic impacts have rightly drawn the focus of the Legislature’s and public’s attention since March 2020, other statewide challenges continue to approach on the horizon. Among these are the impending impacts of climate change, including the hazards that rising seas pose to California’s coast. Scientific estimates suggest the magnitude of sea‑level rise (SLR) in California could be at least half of one foot in 2030 and as much as seven feet by 2100. Moreover, storm surges, exceptionally high “king tides,” or El Niño events could produce notably higher water levels than SLR alone.

When floods hit the road: Resilience to flood-related traffic disruption in the San Francisco Bay Area and beyond

American Association for the Advancement of Science (AAAS) | August 5th, 2020

As sea level rises, urban traffic networks in low-lying coastal areas face increasing risks of flood disruptions. Closure of flooded roads causes employee absen

As sea level rises, urban traffic networks in low-lying coastal areas face increasing risks of flood disruptions. Closure of flooded roads causes employee absences and delays, creating cascading impacts to communities. We integrate a traffic model with flood maps that represent potential combinations of storm surges, tides, seasonal cycles, inter-annual anomalies driven by large-scale climate variability such as the El Niño Southern Oscillation, and sea level rise. When identifying inundated roads, we propose corrections for potential biases arising from model integration. Our results for the San Francisco Bay Area show that employee absences are limited to the homes and workplaces within the areas of inundation, while delays propagate far inland. Communities with limited availability of alternate roads experience long delays irrespective of their proximity to the areas of inundation. We show that metric reach, a measure of road network density, is a better proxy for delays than flood exposure.

Wildfire and Drought: Impacts on wildfire planning, behavior, and effects

National Integrated Drought Information System | March 4th, 2016

The relationship between drought and wildfire can appear to be simple, but the drought and wildfire nexus encompasses a profusion of human and environmental impacts. Imag

The relationship between drought and wildfire can appear to be simple, but the drought and wildfire nexus encompasses a profusion of human and environmental impacts. Images of burning forests, neighborhoods, and “smoked out” communities are all now commonplace. The National Integrated Drought Information System, in partnership with NOAA’s Western Regional Climate Center (WRCC), the California Nevada Applications Program (CNAP, a NOAA Regional Integrated Science Applications team), the Desert Research Institute (DRI), and the National Drought Mitigation Center (NDMC), hosted the Integrating Drought Science and Information into Wildfire Management Workshop in Boise, Idaho on 21-22 October 2015.  The 22 participants in the workshop were invited as representatives of a broad spectrum of expertise including prescribed fire, wildland fire management, climatology, smoke and air quality, fuels management, fire behavior, drought, and policy. In this report, we present the opportunities and challenges the workshop participants identified and the impacts of drought on wildfire. The workshop also provided the opportunity to identify next steps in understanding and addressing drought impacts on wildfire.

Wildfire Impacts on Snowpack Phenology in a Changing Climate Within the Western U.S.

American Geophysical Union (AGU) | July 8th, 2022

Snowpack accumulation and melt are critical for water supply in the western United States. As the number and size of wildfires have increased, it is important to understa

Snowpack accumulation and melt are critical for water supply in the western United States. As the number and size of wildfires have increased, it is important to understand how these events impact the seasonal snowpack. Using data from the Snow Telemetery monitoring network, we quantify the impacts of wildfires on snowpack for various regions across the western U.S. and Alaska. The results indicate that decreases in snowpack tend to occur following fires. Also, the snowmelt period usually begins and finishes earlier in the spring due to the conditions in the burned forests. In regions of the western U.S. that are already experiencing earlier snowmelt due to climate changes, wildfires are further shifting the melt earlier, which could have substantial consequences for water supply and flood risks.