Stralberg D.,Climate Change and Informatics Group |
Stralberg D.,University of Alberta |
Brennan M.,PWA Inc |
Callaway J.C.,University of San Francisco |
And 6 more authors.
PLoS ONE | Year: 2011
Background: Tidal marshes will be threatened by increasing rates of sea-level rise (SLR) over the next century. Managers seek guidance on whether existing and restored marshes will be resilient under a range of potential future conditions, and on prioritizing marsh restoration and conservation activities. Methodology: Building upon established models, we developed a hybrid approach that involves a mechanistic treatment of marsh accretion dynamics and incorporates spatial variation at a scale relevant for conservation and restoration decision-making. We applied this model to San Francisco Bay, using best-available elevation data and estimates of sediment supply and organic matter accumulation developed for 15 Bay subregions. Accretion models were run over 100 years for 70 combinations of starting elevation, mineral sediment, organic matter, and SLR assumptions. Results were applied spatially to evaluate eight Bay-wide climate change scenarios. Principal Findings: Model results indicated that under a high rate of SLR (1.65 m/century), short-term restoration of diked subtidal baylands to mid marsh elevations (-0.2 m MHHW) could be achieved over the next century with sediment concentrations greater than 200 mg/L. However, suspended sediment concentrations greater than 300 mg/L would be required for 100-year mid marsh sustainability (i.e., no elevation loss). Organic matter accumulation had minimal impacts on this threshold. Bay-wide projections of marsh habitat area varied substantially, depending primarily on SLR and sediment assumptions. Across all scenarios, however, the model projected a shift in the mix of intertidal habitats, with a loss of high marsh and gains in low marsh and mudflats. Conclusions/Significance: Results suggest a bleak prognosis for long-term natural tidal marsh sustainability under a high-SLR scenario. To minimize marsh loss, we recommend conserving adjacent uplands for marsh migration, redistributing dredged sediment to raise elevations, and concentrating restoration efforts in sediment-rich areas. To assist land managers, we developed a web-based decision support tool (www.prbo.org/sfbayslr). © 2011 Stralberg et al.
Keener J.,PWA Inc
American Filtration and Separations Society Fall Conference 2013: Innovations in Filter Media and Membranes | Year: 2013
The ability to meet stringent Oil in Water (OIW) regulation limits for produced water discharges is a prevalent issue for conventional produced water treatment equipment. PWA Inc. has completed three field trials in Southeast Asia in 2013 to demonstrate the ability of the regenerable Osorb® media to polish the effluent OIW from traditional processing equipment to < 25 mg/L per OIW discharge regulations. These trials involved installing PWA's OTC006 6″ Test Column loaded with Osorb® media to treat a slip stream of the live produced water. An offshore trial in July 2013 evaluated treatment of produced water from 44 API crude oil production. The effluent from traditional mechanical processing equipment typically ranges from 200-600 mg/L OIW, and the Osorb® media reduced the OIW concentrations by 98.7% from an average 619 mg/L OIW to 8.6 mg/L OIW. An onshore trial in February 2013 at a location that treats offshore produced water evaluated treatment of produced water from 39.4 API crude oil production. The effluent from the existing traditional mechanical processing equipment ranges from 50-400 mg/L OIW, and the Osorb® media reduced the OIW concentrations by 96.6% from an average 85 mg/L OIW to 2.8 mg/L OIW. From this field data, the Osorb® media has proven to remove residual OIW from traditional mechanical processing equipment to concentrations far below discharge regulations of 25 mg/L. These discharge regulations can be met with less than 1-2 minutes residence time in the Osorb® media bed while only requiring a single pass through the system.
Panella L.,U.S. Department of Agriculture |
Lewellen R.T.,PWA Inc |
Webb K.M.,U.S. Department of Agriculture
Journal of Plant Registrations | Year: 2011
FC1018 (Reg. No. GP-273, PI 658059), FC1019 (Reg. No. GP-274, PI 658060), FC1020 (Reg. No. GP-275, PI 658061), and FC1022 (Reg. No. GP-276, PI 658062) sugarbeet (Beta vulgaris L.) germplasms were released in 2009 from seed lots 05- FC1018; 05-FC1019; 07-, 08-, or 09-FC1020; and 05-FC1022, respectively, and tested under those designations. They were developed by the USDA-ARS at Fort Collins, CO and Salinas, CA in cooperation with the Beet Sugar Development Foundation, Denver, CO. All four germplasms are populations in fertile cytoplasm and segregate for self-sterility, multigermity, hypocotyl color, and the Rz1 gene, which confers resistance to some strains of Beet necrotic yellow vein virus, the causal agent of rhizomania. FC1018, FC1019, and FC1020 have moderate tolerance to root-rotting strains (AG- 2-2) of Rhizoctonia solani Kühn (the causal agent of Rhizoctonia root and crown rot), Cercospora beticola Sacc. (the causal agent of Cercospora leaf spot), Beet curly top virus (BCTV), and Aphanomyces cochlioides Drechsl., which causes Aphanomyces root rot (Aphanomyces black root). They are populations that can be used to select disease-resistant, multigerm pollinator parents. FC1022 has a moderate tolerance to BCTV and had a relatively high sucrose concentration at Salinas when tested in a fi eld infested with rhizomania. Because of a large percentage of monogerm seedballs (45%) and O-type parentage, it should be possible to select monogerm, O-type lines from FC1022. © Crop Science Society of America.
Langridge S.M.,Stanford University |
Hartge E.H.,Stanford University |
Clark R.,Moss Landing Marine Laboratories |
Arkema K.,University of Washington |
And 10 more authors.
Ocean and Coastal Management | Year: 2014
Sea-level rise, potential changes in the intensity and frequency of storms, and consequent shoreline erosion and flooding will have increasing impacts on the economy and culture of coastal regions. A growing body of evidence suggests that coastal ecosystems-natural infrastructure-can play an important role in reducing the vulnerability of people and property to these impacts. To effectively inform climate adaptation planning, experts often struggle to develop relevant local and regional information at a scale that is appropriate for decision-making. In addition, institutional capacity and resource constraints often limit planners' ability to incorporate innovative, scientifically based approaches into planning. In this paper, we detail our collaborative process in two coastal California counties to account for the role of natural infrastructure in climate adaptation planning. We used an interdisciplinary team of scientists, economists, engineers, and law and policy experts and planners, and an iterative engagement process to (1) identify natural infrastructure that is geographically relevant to local jurisdictional planning units, (2) refine data and models to reflect regional processes, and (3) develop metrics likely to resonate within the local decision contexts. Using an open source decision-support tool, we demonstrated that protecting existing natural infrastructure-including coastal dunes and wetlands-could reduce the vulnerability of water resource-related structures, coastal populations, and farmland most exposed to coastal flooding and erosion. This information formed part of the rationale for priority climate adaptation projects the county governments are now pursuing. Our collaborative and iterative approach, as well as replicable use of an open source decision-support tool, facilitated inclusion of relevant natural infrastructure information into regional climate adaptation planning processes and products. This approach can be applied in diverse coastal climate adaptation planning contexts to locate and characterize the degree to which specific natural habitats can reduce vulnerability to sea-level rise and storms. © 2014 Elsevier Ltd.
Hawley R.J.,Colorado State University |
Hawley R.J.,Sustainable Streams LLC |
Bledsoe B.P.,Colorado State University |
Stein E.D.,Southern California Coastal Water Research Project |
And 2 more authors.
Journal of the American Water Resources Association | Year: 2012
We present a novel channel evolution model (CEM) that qualitatively describes morphologic responses of semiarid channels to altered hydrologic and sediment regimes associated with urbanization (hydromodification). The CEM is based on southern California data from 83 detailed channel surveys, hundreds of synoptic surveys, and historical analyses of aerial photographs along 14 reaches. Channel evolution sometimes follows the well-known sequence described by Schumm et al. (Incised Channels: Morphology, Dynamics, and Control, Water Resources Publications, Littleton, Colorado, 1984) for incising, single-thread channels; however, departures from this sequence are common and include transitions of single thread to braided evolutionary endpoints, as opposed to a return to quasi-equilibrium single-thread planform. Thresholds and risk factors associated with observed channel response are also presented. In particular, distance to grade control and network position emerged as key controls on channel response trajectory. The CEM and quantitative extensions provide managers with a framework for understanding channel responses and rehabilitation alternatives, and may be transferable to other semiarid settings. It also offers insights regarding channel susceptibility to hydromodification, highlights key boundary conditions for high-risk channels, and underscores critical knowledge gaps in predicting the complex, discontinuous response trajectories that are highly prevalent in urbanized watersheds. © 2012 American Water Resources Association.
PWA Inc | Date: 2011-06-20