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Hydrometeorological links to high streamflow events (HSFEs), 1950–2014, for the Mystic and Charles watersheds in the Metro Boston region of Massachusetts are examined. HSFEs are defined as one or more continuous days of streamflow above the mean annual maxima for a selected gauge in each basin. There are notable differences in the HSFEs for these two basins. HSFEs last from 1 to 3 days in the Mystic basin, while HSFEs for the Charles can last from 3 to 9 days. The majority of Mystic HSFEs are immediately preceded by extreme precipitation (occurring within 24 h), while only half of those for the Charles are preceded by extreme precipitation (in this case occurring 2–5 days earlier). While extreme precipitation events are often linked to HSFEs, other factors are often necessary in generating high streamflow, particularly for the Charles, as more than 50% of HSFEs occur at times when streamflow, soil moisture, and total precipitation are statistically above average for a period of at least 2 weeks before the HSFE. Approximately 52% and 80% of HSFEs occur from February to June for the Mystic and Charles, respectively, and these HSFEs are frequently linked to the passage of strong coastal lows, which produce extreme precipitation in the form of both rain and snow. For these coastal lows, Mystic HSFEs are linked to a strong moisture feed along the Massachusetts coastline and intense precipitation, while Charles HSFEs are linked to strong cyclones located off the Mid-Atlantic and longer-duration precipitation. more...

The current study addresses the issue of vulnerability assessment of transportation systems to climate change, with the purpose of improving current indicator-based approaches in this field...

The impacts of recent extreme weather events as well as the evidence of our changing climate has sparked a new sense of urgency in resiliency planning in the Northeast U.S. Vulnerability to climate change impacts is not limited to the built environment, but rather extends to the sociotechnical systems that include the perceptions, values, preferences and patterns of behavior of various groups of human stakeholders. To more fully incorporate the human dimension into resiliency planning we must elicit and apply the ecological wisdom (EW) of local residents and stakeholders. The complexity of EW has yet to be fully described; this paper does not develop a new definition, but rather, expands the definition of EW to include local knowledge of urban dwellers that can be tapped to more effectively inform resiliency planning. We present a recent example that demonstrates how participatory action research (PAR) methods can be used to gather EW that would not ordinarily be obtained by more traditional vulnerability assessment methods. Our case study is based upon the Alewife Disaster Preparedness and Community Resiliency Planning Initiative of the City of Cambridge, Massachusetts. Despite the limited scope of this PAR project, a surprising number of useful observations and recommendations were obtained, which could serve to enhance the ongoing resiliency planning of the City of Cambridge. Local stakeholders also suggested a number of what W.F. Whyte described as “social inventions” for strengthening the quality of disaster preparedness and community resiliency within the Alewife community. We highlight the need to give more attention to the human dimension of resiliency planning by better understanding how a variety of local stakeholders’ experience climate-related disasters, perceive the effectiveness of alternative disaster preparedness and community resiliency strategies, and determine their willingness to contribute to ongoing resiliency planning taking place within their community. more...

A landslide susceptibility mapping study was performed using dynamic hillslope hydrology. The modified infinite slope stability model that directly includes vadose zone soil moisture (SM) was applied at Cleveland Corral, California, US and Krishnabhir, Dhading, Nepal. The variable infiltration capacity (VIC-3L) model simulated vadose zone soil moisture and the wetness index hydrologic model simulated groundwater (GW). The GW model predictions had a 75% NASH-Sutcliffe efficiency when compared to California’s in-situ GW measurements. The model performed best during the wet season. Using predicted GW and VIC-3L vadose zone SM, the developed landslide susceptibility maps showed very good agreement with mapped landslides at each study region. Previous quasi-dynamic model predictions of Nepal’s hazardous areas during extreme rainfall events were enhanced to improve the spatial characterization and provide the timing of hazardous conditions. more...

This study examines U.S. Northeast daily precipitation and extreme precipitation characteristics for the 1979–2008 period, focusing on daily station data. Seasonal and spatial distribution, time scale, and relation to large-scale factors are examined. Both parametric and nonparametric extreme definitions are considered, and the top 1% of wet days is chosen as a balance between sample size and emphasis on tail distribution. The seasonal cycle of daily precipitation exhibits two distinct subregions: inland stations characterized by frequent precipitation that peaks in summer and coastal stations characterized by less frequent but more intense precipitation that peaks in late spring as well as early fall. For both subregions, the frequency of extreme precipitation is greatest in the warm season, while the intensity of extreme precipitation shows no distinct seasonal cycle. The majority of Northeast precipitation occurs as isolated 1-day events, while most extreme precipitation occurs on a single day embedded in 2–5-day precipitation events. On these extreme days, examination of hourly data shows that 3 h or less account for approximately 50% of daily accumulation. Northeast station precipitation extremes are not particularly spatially cohesive: over 50% of extreme events occur at single stations only, and 90% occur at only 1–3 stations concurrently. The majority of extreme days (75%–100%) are related to extratropical storms, except during September, when more than 50% of extremes are related to tropical storms. Storm tracks on extreme days are farther southwest and more clustered than for all storm-related precipitation days. more...

The vulnerability of our nation’s transportation infrastructure to climate change and extreme weather is now well documented and the transportation community has identified numerous strateg...

With rising sea levels and possible storm intensification due to climate change, current United States urban coastal flood management strategies will be challenged. Due to limitations of current flood management strategies, evacuation is likely to become increasingly prominent in many coastal areas. Thus it is important to think critically about challenges for successful evacuation planning, particularly for vulnerable communities. This paper brings together the evacuation planning, climate change and environmental justice literatures. We describe the unique challenges that environmental justice communities face with evacuation, and identify best practice guidelines to improve the quality of evacuation planning for these communities. The guidelines presented, while not comprehensive, provide a framework for planners and policymakers to consider when developing evacuation plans, both for current and future climate conditions, and could improve the quality of evacuation planning. more...

The Energy Policy Act of 2005 and the Energy Independence and Security Act (EISA) of 2007 were enacted to reduce the U.S. dependency on foreign oil by increasing the use of biofuels. The increased demand for biofuels from corn and soybeans could result in an increase of nitrogen flux if not managed properly. The objectives of this study are to estimate nitrogen flux from energy crop production and to identify the catchment areas with high nitrogen flux. The results show that biofuel production can result in an increase of nitrogen flux to the northern Gulf of Mexico from 270 to 1742 thousand metric tons. Using all cellulosic (hay) ethanol or biodiesel to meet the 2022 mandate is expected to reduce nitrogen flux; however, it requires approximately 25% more land when compared to other scenarios. Producing ethanol from switchgrass rather than hay results in three-times more nitrogen flux, but requires 43% less land. Using corn ethanol for 2022 mandates is expected to have double the nitrogen flux when compared to the EISA-specified 2022 scenario; however, it will require less land area. Shifting the U.S. energy supply from foreign oil to the Midwest cannot occur without economic and environmental impacts, which could potentially lead to more eutrophication and hypoxia. more...

In this paper, the authors present results from a study of climate change and community adaptation, focusing on two African American communities on the Eastern Shore of the Chesapeake Bay. These two communities are representative of small, resource-poor communities that are particularly prone to increased flooding, storms, and erosion accompanying climate change. The authors frame their research within a focus on distributive and procedural justice, including considerations of the role of adaptation capacity and vulnerability. They use methods from cognitive–environmental anthropology and psychometrics to ground a participatory and multidisciplinary approach that emphasizes community participation and the sharing of scientific and program information on climate change and adaptation. Their results suggest that community members have a holistic understanding of climate change, recognize a wide range of potential community and individual impacts, face specific vulnerabilities, and are organized through their churches to engage in efforts to reduce the impacts of increased flooding and storms on their communities. more...

The objective of this study was to investigate the presence of trends in extreme precipitation (denoted MAXP and defined as the annual maximum daily precipitation depth) time series for coastal northern New England and to assess changes in the magnitude of the so-called 100-year storm. MAXP depths from 48 stations with long, continuous records in Maine, New Hampshire, and Massachusetts were analyzed. At those same stations, the number of daily precipitation depths ≥ 2i n: (51 mm, denoted as GT2in) was also quantified for each year. Although the seasonally averaged MAXP was found to be fairly uniform throughout the year, the frequency of MAXP is highest during August through October, the typical hurricane season in New England. The presence of trends in MAXP and GT2in was evaluated over four time frames (1954-2005, 1954-2008, 1970-2005, and 1970-2008) using two statistical methods (linear regression and the Mann-Kendall trend test) and at two scales (at-site and regional). The trend analysis over the time period 1954-2005 indicated that MAXP was amazingly stationary; however, a trend in GT2in was found at some stations. More trends in both MAXP and GT2in were present in the time period 1954-2008. The majority of stations in southern New Hampshire and eastern Massachusetts showed evidence of trends in MAXP (but not GT2in) for the time period 1970-2008. That the number of trends in MAXP increased despite the shorter record length suggests a strong increase in the magnitude of extreme precipitation in northern coastal New England in the last few decades. The stationarity of the 1954-2005 record was confirmed by the regional trend analysis, as was the presence of stronger trends in coastal stations when the record was extended through 2008. Most stations that had trends in MAXP also had trends in GT2in. The generalized extreme value (GEV) distribution was used to estimate 100-year precipitation depth quantiles for the 1954-2005 record, which were then compared with Technical Paper No. 40 (TP-40) 100-year, 24-h precipitation depths. Estimates for stations along coastal Massachusetts, New Hampshire, and Maine all exceeded 7 in. (180 mm) and exceeded TP-40 by 1 in. (25 mm) or more. Stations in northeastern Massachusetts, southeastern New Hampshire, and southern Maine exceeded 8 in. (200 mm) and also exceeded TP-40 estimates by more than 2 in. (51 mm). These findings indicate that TP-40 underrepresents coastal storm depths. This study, as well as recent record-breaking events in northern New England, strongly suggests the need for updating of design storm estimates. Furthermore, extreme precipitation events of longer than one-day duration have caused large-scale flooding in the region over the last decade. The magnitude of longer duration storms (particularly two-day storms) may also be increasing, calling for engineered infrastructure that can accommodate increases in both storm magnitude and duration. DOI: 10.1061/(ASCE)HE.1943-5584.0000303. © 2011 American Society of Civil Engineers. more...

The literature on managing environmental hazards in complex human-natural systems increasingly acknowledges the importance of integrating diverse stakeholder mental models into decision-making. Participatory Fuzzy Cognitive Mapping (FCM) provides an effective tool in this process, as it allows representation of mental models as complex causal networks that aid in the study of knowledge and understandings. While most participatory FCM research has studied mental model variation using graph theory and other structural metrics, our goal is to demonstrate a generalisable approach for analysing perspectives and content. We use a novel method of knowledge categorisation to identify variation among stakeholder mental models and explore its implications for social learning and collaboration. In our case study of flood managers in Boston, Massachusetts, our findings include identification of knowledge gaps, differing priorities among individuals and across jurisdictional scales and opportunities for learning and collaboration. more...

Pressing challenges in urban adaptation planning to extreme events include: (1) involving vulnerable populations in the impacted area; and (2) employing a multi-level stakeholder collaborative process to build consensus for action. These processes become even more important as adaptive urban planning is recognized as an effective governance model for adaptation to climate change. In a case study of a low to moderate income community vulnerable to present and increased coastal storm surge flooding, the Supported Community Planning Process was employed because (a) most residents of East Boston affiliate primarily with their own local neighborhoods and (b) the residents need targeted expertise to help them understand some of the scientific and technical aspects of adaptation planning. Collaboration was necessary among three sets of critical stakeholders interested in adaptation strategies in East Boston — the local residents and small businesses, the City of Boston, and the agencies that provide infrastructure services — because some adaptation actions will collectively protect assets of all. The overall process occurred successfully because of positive, knowledgeable, and direct exchange of values and goals. The research illustrates how marginalized populations can be effectively engaged in urban adaptation planning, and how that process can be combined in multi-level stakeholder collaborative planning so that plans might be developed that meet multiple shared and individual goals in a cost-effective manner. more...

Summary Rainwater harvesting, broadly defined as the collection and storage of surface runoff, has a long history in supplying water for agricultural purposes. Despite its significance, rainwater harvesting in small reservoirs has previously been overlooked in large-scale assessments of agricultural water supply and demand. We used a macroscale hydrological model, observed climate data and other physical datasets to explore the potential role of small, localized rainwater harvesting systems in supplying water for irrigated areas. We first estimated the potential contribution of local water harvesting to supply currently irrigated areas. We then explored the potential of supplemental irrigation applied to all cropland areas to increase crop evapotranspiration (or green water flow), using locally stored surface runoff in small reservoirs for different scenarios of installed reservoir capacity. The estimated increase in green water flow varied between 623 and 1122 km 3 a −1 . We assessed the implications of this increase in green water flows for cereal production by assuming a constant crop water productivity in areas where current levels of crop yield are below global averages. Globally, the supplemental irrigation of existing cropland areas could increase cereal production by ∼35% for a medium variant of reservoir capacity, with large potential increases in Africa and Asia. As small reservoirs can significantly impact the hydrological regime of river basins, we also assessed the impacts of small reservoirs on downstream river flow and quantified evaporation losses from small reservoirs. more...

summary We analyzed observed daily evapotranspiration (DET) at 18 sites having measured DET and ancillary climate data and then used these data to compare the performance of three common methods for estimating potential evapotranspiration (PET): the Turc method (Tc), the Priestley–Taylor method (PT) and the Penman–Monteith method (PM). The sites were distributed throughout the State of Florida and represent a variety of land cover types: open water (3), marshland (4), grassland/pasture (4), citrus (2) and forest (5). Not surprisingly, the highest DET values occurred at the open water sites, ranging from an average of 3.3 mm d � 1 in the winter to 5.3 mm d � 1 in the spring. DET at the marsh sites was also high, ranging from 2.7 mm d � 1 in winter to 4.4 mm d � 1 in summer. The lowest DET occurred in the winter and fall seasons at more...

article i nfo Article history: Accepted 8 February 2008 Available online xxxx Using the Regional Atmospheric Modeling System (RAMS) we show that agricultural intensification and irrigation can modify the surface moisture and energy distribution, which alters the boundary layer and regional convergence, mesoscale convection, and precipitation patterns over the Indian monsoon region. Four experiments were conducted to simulate a rain event from 16 to 20 July 2002 over the Indian region: (i) a control with Global Land Cover land use and observed Normalized Difference Vegetation Index, (ii) an irrigated crop scenario, (iii) a non-irrigated crop scenario, and (iv) a scenario for potential (natural) vegetation. Results indicate that even under active monsoon conditions, the simulated surface energy and moisture flux over the Indian monsoon region are sensitive to the irrigation intensity and this effect is more pronounced than the impact of land use change from the potential vegetation to the agricultural landscape. When model outputs were averaged over the south Asia model domain, a statistically significant decrease in mean sensible heat flux between the potential vegetation and the irrigated agriculture scenarios of 11.7 Wm −2 more...

Study region: Water stress and over-allocation are at the forefront of water management and policy challenges in Australia, especially in the Murray–Darling Basin (MDB). Because irrigated agriculture is a major social and economic component of the MDB, farmer decision-making plays a major role in water sustainability in the region.Study focus: This study used a fuzzy cognitive mapping methodology, ‘mental modeling’, to understand the perceived constraints of irrigator water-use decisions in the MDB, for two different types of irrigation: permanent and annual crops. The approach elicits and documents irrigator insights into the complex and networked nature of irrigation water use decisions in relation to farm-based dynamics.New hydrological insights for the region: Results suggest support for greater local and irrigator involvement in water management decisions. Many, if not most, of the irrigators understood the need for, or at least the inevitability of, governmental policies and regulations. However, a lack of accountability, predictability, and transparency has added to the uncertainty in farm-based water decision-making. Irrigators supported the concept of environmental sustainability, although they might not always agree with how the concept is implemented. The mental modelling approach facilitated knowledge sharing among stakeholders and can be used to identify common goals. Future research utilizing the mental modelling approach may encourage co-management and knowledge partnerships between irrigators, water managers and government officials. Refereed/Peer-reviewed more...

Human water use can place considerable stress on hydrologic systems. Humans directly affect the water cycle through water withdrawals and return flows. Aside from climate change, humans indirectly impact hydrologic systems through dam building, land use change, and urbanization. Given the increasing incidence of water overdraft and water scarcity globally, there is a growing need to understand and quantify these effects so that appropriate water management and policy decisions can be made both in the United States and abroad. Massachusetts, in the northeastern United States, is located in a “water-rich” region, and yet issues of water overdraft and exceptional low flows have been documented throughout the state. This study demonstrates the application of water use regimes for characterizing the water balance in two suburbanized basins in eastern Massachusetts: The Charles River watershed (CRW) and the Ipswich River watershed (IRW). Water use regimes categorize river basins based on the magnitude o... more...

With dense population and development along its coastline, the northeastern United States is, at present, highly vulnerable to coastal flooding. At five sea level stations in the United States, from Massachusetts to New Jersey, sea level rise (SLR) trends and tidal effects were removed from the hourly sea level time series and then frequency analysis was performed on the positive remaining anomalies that represent storm surge heights. Then using eustatic SLR estimates for lower and higher greenhouse gas emissions scenarios and assumed trends in local sea level rise, new recurrence intervals were determined for future storm surges. Under the higher emissions scenario, by 2050, the elevation of the 2005 100-year event may be equaled or exceeded at least every 30 years at all sites. In more exposed US cities such as Boston, Massachusetts and Atlantic City, New Jersey, this could occur at the considerably higher frequency of every 8 years or less. Under the lower emissions scenario, by 2050, the elevation of the 2005 100-year event may be equaled or exceeded at least every 70 years at all sites. In Boston and Atlantic City, this could occur every 30 years or less. more...

Tropical deforestation has many consequences, amongst which alteration of the hydrological cycle and loss of habitat and biodiversity are the focus of much public interest and scientific research. Here we examine the potential biodiversity and hydrological impacts of an extreme deforestation scenario - the loss of all tropical forest areas currently identi- fied by the World Wildlife Fund as being threatened. Existing tropical forest areas are first classified according to two categories of biological distinctiveness - high and low - using indicators developed by the WWF. We apply the tropical deforestation scenario to a macro- scale hydrologic model, keeping track of the share of change in basin runoff that originates from the deforestation of areas of high versus low biological distinctiveness and where that change could impact human populations. Of particular interest are those basins where loss of the most threatened tropical forest areas would give rise to significant biodiversity loss and to potentially large hydrological impacts. In such cases it is conceivable that biodiver- sity conservation could "free-ride" on the concerns of resident populations to maintain the forests for the purpose of minimizing hydrological change. Where such an outcome seems likely, biodiversity conservation efforts might be better targeted elsewhere, perhaps to basins where the loss of forest areas with high biological distinctiveness would have less population impacts, hence requiring an alliance between biological and hydrological interests to gain sufficient social and financial support for conservation. more...

We combined several district-level and state-level data sets of rice cropping in India to develop a single dataset of district-level rice cropping systems for all of India in 1999–2000. The data set contains district-level areas for 34 different single-, double-, and triple-cropping combinations (e.g., rice–rice, rice–rice–pulse, rice–pulse–fibrecrop, rice–wheat, and rice–fallow). The dataset specifies cropping by season (e.g., Kharif and Rabi) and area in two water management systems (irrigated or rainfed) for each cropping system in each district. The total rice sown area is 44.9 million hectares (Mha), 91% in the Kharif (wet) season. Total rice land area was 41.6 Mha, with upland rice accounting for 13% of this area. Rainfed rice (including upland and deepwater) accounted for 44% of the total rice sown area, and rice–fallow for 38% of the total rice sown area. The total multiple cropping area with rice occupied 17.6 Mha, with dominant systems being rice–wheat (8.8 Mha), rice–pulse (3.2 Mha), rice–rice (2.2 Mha), and rice–oilseed (1.2 Mha, including rice–groundnut). We combined these maps with a simple, monthly time-step water balance model to estimate irrigation water demand for irrigated rice by district; total national demand was 200 km 3 y −1 . A complete national, district-level set of maps and data of rice cropping systems and water management will be useful as inputs to a range of studies on agricultural productivity, resource use, and environmental impacts of rice agriculture. more...

This study demonstrates the use of globally available Earth system science data sets for water assessment in otherwise information-poor regions of the world. Geospatial analysis at 8 km resolution shows that 64% of Africans rely on water resources that are limited and highly variable. Where available, river corridor flow is critical in augmenting local runoff, reducing impacts of climate variability, and improving access to freshwater. A significant fraction of cropland resides in Africa's driest regions, with 39% of the irrigation nonsustainable. Chronic overuse and water stress is high for 25% of the population with an additional 13% experiencing drought-related stress once each generation. Paradoxically, water stress for the vast majority of Africans typically remains low, reflecting poor water infrastructure and service, and low levels of use. Modest increases in water use could reduce constraints on economic development, pollution, and challenges to human health. Developing explicit geospatial indicators that link biogeophysical, socioeconomic, and engineering perspectives constitutes an important next step in global water assessment. more...

Probable maximum precipitation (PMP) is the conceptual construct that defines the magnitude of extreme storms used in the design of dams and reservoirs. In this study, the value and utility of applying multifractal analysis techniques to systematically calculate physically meaningful estimates of maximum precipitation from observations in the eastern United States is assessed. The multifractal approach is advantageous because it provides a formal framework to infer the magnitude of extreme events independent of empirical adjustments, which is called the fractal maximum precipitation (FMP), as well as an objective estimate of the associated risk. Specifically, multifractal (multiscaling) behavior of maximum accumulated precipitation at daily (327 rain gauges) and monthly (1400 rain gauges) timescales, as well as maximum accumulated 6-hourly precipitable water fluxes for the period from 1950 to 1997 were characterized. Return periods for the 3-day FMP estimates in this study ranged from 5300 to 6200 yr. The multifractal parameters were used to infer the magnitude of extreme precipitation consistent with engineering design criterion (e.g., return periods of 10 6 yr), the design probable maximum precipitation (DPMP). The FMP and DPMP were compared against PMP estimates for small dams in Pennsylvania using the standard methodology in engineering practice (e.g., National Weather Service Hydrometeorological Reports 51 and 52). The FMP estimates were usually, but not always, found to be lower than the standard PMP (FMP/PMP ratios ranged from 0.5 to 1.0). Furthermore, a high degree of spatial variability in these ratios points to the importance of orographic effects locally, and the need for place-based FMP estimates. DMP/PMP ratios were usually greater than one (0.96 to 2.0), thus suggesting that DPMP estimates can provide a bound of known risk to the standard PMP. more...

Conventional methods for estimating the average return period, E(T), and failure risk, R, generally ignore the impact of persistence in annual streamflows on associated probabilistic statements and streamflow statistics. Recent evaluations of streamflow observations indicate statistically significant serial correlations ~persistence! associated with annual low flows in the United States. We define the average occurrence interval E(T) as the expected time to the first event, and we present a method for estimating E(T) and R in the presence of persistence. We show that for observed ranges of persistence, E(T) can be nearly 100% greater and R more than 20% lower than conventional estimates. This implies that the expected design life of a system is longer when persistence is taken into account. Also, by ignoring persistence, low flow quantiles may be underestimated by 50% or more. An evaluation of the effect of persistence on drought risk estimation across the U.S. is presented. more...

The Infrastructure and Climate Network (ICNet) was established to develop collaborative networks and platforms needed to integrate the multidisciplinary areas of climate change, pavement design and performance, and economics. Preliminary network activities, described in this paper, have rapidly expanded knowledge of pavement performance under future climates and provide insights for future research. Specifically, increases in the frequency and/or severity of many types of extreme weather events have already been observed; projected future changes in air temperature, rainfall, sea level rise and hurricanes on pavement performance are significant; and future costs are expected to increase very significantly and non-linearly. Combining these findings, the authors offer a set of recommendations for future research to address their key research question: How does climate non-stationarity differentially impact transportation infrastructure design, performance and life span? more...

Trends in flood and low flows in the US were evaluated using a regional average Kendall's S trend test at two spatial scales and over two timeframes. Field significance was assessed using a bootstrap methodology to account for the observed regional cross-correlation of streamflows. Using a 5% significance level, we found no evidence of trends in flood flows but did find evidence of upward trends in low flows at the larger scale in the Midwest and at the smaller scale in the Ohio, the north central and the upper Midwest regions. A dramatically different interpretation would have been achieved if regional cross-correlation had been ignored. In that case, statistically significant trends would have been found in all but two of the low flow analyses and in two-thirds of the flood flow analyses. We show that the cross-correlation of flow records dramatically reduces the effective number of samples available for trend assessment. We also found that low flow time series exhibit significant temporal persistence. Even when the serial correlation was removed from the time series, significant trends in low flow series were apparent, though the number of significant trends decreased. more...

The current atmospheric mixing ratio of nitrous oxide (N2O), a chemically significant trace gas, is increasing at a rate of 0.25−0.31% yr-1, apparently well correlated with human activity. Better quantification of all N2O sources is required in efforts to stabilize this rate of increase. N2O emissions from the composting of wastewater sludge and livestock wastes were measured during 1993 and 1994 using enclosure methods. Static chambers were placed on the surface of the compost piles, and N2O mixing ratios within the chamber headspace were measured over time from which fluxes were calculated. The flux measurements resulted in mass-based emission factors of 0.7 g of N2O (dry kg)-1 and 0.5 g of N2O (dry kg)-1 for the sludge compost and the livestock waste compost, respectively. The derived emission factors were used in conjunction with recent waste generation and disposal statistics to estimate potential global N2O emissions from the treatment of organic wastes. Livestock waste treatment appears to hold the... more...

A nitrogen transport and mass-balance study was performed at a large-scale composting facility in order to evaluate the impact of such facilities on groundwater quality. In the soil zone, soil moisture NO3-N concentrations in excess of 100 mg/L were consistently observed at depths as great as 1.5 m below a farm waste windrow, and reached levels as high as 900 mg/L by the end of the composting process. There was a strong inverse relationship between NH4-N changes in the farm waste and NO3-N changes in the soil directly below the windrow. Little attenuation occurred as NO3-N was transported downward through the soil. NO3-N in soil moisture 1.5 m below the yard waste remained at ambient levels for much of the two-month sampling period. Quantified nitrogen losses during the composting process were nearly 10 times higher in the farm waste than in the yard waste. Of the nitrogen species sampled, dissolved NO3-N was by far the predominant pathway for nitrogen loss from the composting farm waste, while gaseous N2O losses predominated in the composting yard waste. The major factors determining the degree to which nitrogen was lost during the composting process were waste characteristics of: the type of organic carbon present, the percentage of inorganic nitrogen, the bulk density, and moisture content. more...

Highway tunnels along the coast are critical infrastructure and represent one of the more sensitive components of a transportation network to coastal flooding. By their very nature, large portions of these tunnels are beneath present sea level and the tunnel entrances and the equipment necessary to operate the tunnels such as vent buildings may or may not be above present flood thresholds. The Central Artery/Tunnel (CA/T) system in coastal Boston, Massachusetts USA is a vital link in the regional transportation network and is comprised of more than 160 lane-miles (more than half of them in tunnels), 6 interchanges and 200 bridges. While not examined here, the CA/T system relies upon other infrastructure systems to fully function, such as the electrical grid. The ADvanced CIRCulation model (ADCIRC) coupled with the Simulating WAves Nearshore (SWAN) Model was used for storm surge modeling. SLR scenarios were selected for four distinct time periods (2013, 2030, 2070, and 2100) to bracket the potential future sea level rise outcomes for the Boston Harbor area and a Monte Carlo statistical approach was utilized to estimate the probability of flooding throughout the Boston Harbor region. The vulnerability analysis was based solely upon exposure, defined as flooding experienced at CA/T systems when at the thresholds of the design flood standards that governed the original design of the CA/T. The extent of flood vulnerability under current climatic conditions is fairly limited with low exceedance probabilities. By late 21st century, however, there is considerable flooding at Tunnel Portals and other buildings and structures. Both local adaptation options such as flood walls protecting individual assets or gates protecting tunnel portals and regional plans blocking major flood pathways were evaluated. In complex systems such as the CA/T, the number and spatial extent of vulnerable areas increase over time as sea level rises and the intensity of storms increase, suggesting that local adaptations may be most applicable in the near-term and regional based adaptations (safeguarding multiple areas for multiple stakeholders) will become more cost effective and necessary solutions in the long-term. Focusing first on local actions also means that the CA/T owner is less reliant on other organizations and agencies to manage the CA/T adaptation as it will own the land necessary for any changes and will only have to manage its own efforts. The regional plan has the co-benefits that it will protect more assets in the region than just the CA/T and there is the possibility that the cost can be shared among more agencies and organizations than just the owner. more...

East Boston, Massachusetts is a coastal community in the northeastern USA that faces a growing threat from coastal storm surge flooding due to rising sea levels. Due to its relatively low income levels, large number of recent immigrants, and current environmental stresses, it is also a community suffering from environmental injustice. As complicated as adaptation to climate change may be, it is even more complicated when looking at the particularly complex situation of environmental justice. In this community it is found that the community did not have an adaptation perspective or knowledge of any resources that could assist them in this challenge. The residents also seem to have little power over the management of their community with the result that adaptation decisions may be made by processes, institutions and individuals from outside the community. All adaptation options have some disincentives for them; with high costs being common to all. Their cultural knowledge also limits their viewpoints on alternatives. Participants believe they need more information on climate change, how it will impact them, and what resources are available to assist them. Incentives for adaptation include a very broad ranging, accepting view of climate change impacts, commitment to their communities, eagerness to continue learning about climate change, and recognition that there is the need for an integrated regional flood management planning process that is stakeholder driven. more...

Decades of agricultural growth has led to the over appropriation of Yakima water and the ecological integrity of the Basin has been compromised. We evaluate the impact of current water allocation on the natural flow regime of the Yakima River using the Indicators of Hydrologic Alteration/Range of Variability Analysis and by quantifying indicators of ecosurplus and ecodeficit. We analyze the sustainability of the current water allocation scheme based on a range of sustainability criteria, from weak to strong to environmentally sustainable. Economic efficiency is assessed by describing the current allocation framework and suggesting ways to make it more efficient. Our IHA/RVA analysis suggests that the allocation of water in the Yakima River has resulted in a highly altered flow regime. Ecodeficit is far in excess of ecosurplus. We conclude that this allocation scheme is weakly sustainable, if sustainable at all, in its current framework. The allocation of water is also not economically efficient and we suggest that a reallocation of water rights may be necessary in order to achieve this objective. The creation of water markets to stimulate voluntary water rights transactions is the best way to approach economic efficiency. The first step would be to extend beneficial use requirements to include instream flows, which would essentially allow individuals to convert offstream rights into instream rights. The Washington trust water rights program was implemented as a means of creating a water market, which has contributed to the protection of instream flows, however more needs to be done to create an ideal water rights market so that rights migrate to higher valued uses, many of which are met instream. However, water markets will likely not solve the Yakima's water allocation problems alone; some degree of regulation may still be necessary. more...

John R. Mecikalski1, David M. Sumner2, Jennifer M. Jacobs3, Chandra S. Pathak4, Simon J. Paech5, and Ellen M. Douglas6 1University of Alabama in Huntsville, Huntsville, Alabama 2U. S. Geological Survey (USGS), Orlando, Florida 3University of New Hampshire, Durham, New Hampshire 4South Florida Water Management District, West Palm Beach, Florida 5University of Alabama in Huntsville, Huntsville, Alabama 6University of Massachusetts, Boston, Massachusetts USA more...

[1] Agricultural water use accounts for around 70% of the total water that is withdrawn from surface water and groundwater. We use a new, gridded, global-scale water balance model to estimate interannual variability in global irrigation water demand arising from climate data sets and uncertainties arising from agricultural and climate data sets. We used contemporary maps of irrigation and crop distribution, and so do not account for variability or trends in irrigation area or cropping. We used two different global maps of irrigation and two different reconstructions of daily weather 1963–2002. Simulated global irrigation water demand varied by ∼30%, depending on irrigation map or weather data. The combined effect of irrigation map and weather data generated a global irrigation water use range of 2200 to 3800 km3 a−1. Weather driven variability in global irrigation was generally less than ±300 km3 a−1, globally ( more...

[1] India has one of the most intensive and spatially extensive irrigation systems in the world developed during the1960s under the agricultural Green Revolution (GR). Irrigated landscapes can alter the regional surface energy balance and its associated temperature, humidity, and climate features. The main objective of this study is to determine the impacts of increased irrigation on long-term temperature trends. An analysis of the monthly climatological surface data sets at the regional level over India showed that agriculture and irrigation can substantially reduce the air temperature over different regions during the growing season. The processes associated with agriculture and irrigation-induced feedback are further diagnosed using a column radiation-boundary layer model coupled to a detailed land surface/hydrology scheme, and 3-D simulations using a Regional Atmospheric Modeling System. Both the modeling and observational analysis provide evidence that during the growing season, irrigation and agricultural activity are significantly modulating the surface temperatures over the Indian subcontinent. Therefore irrigation and agricultural impacts, along with land use change, and aerosol feedbacks need to be considered in regional and global modeling studies for climate change assessments. more...

Accurate determination of potential and reference evapotranspiration is essential to estimate water balances. In most standardized methods, such as the Penman-Monteith and Priestley-Taylor methods, net radiation is one of the most important forcing data. Unfortunately few stations measure net radiation. Instead, net radiation is typically calculated from solar radiation, ancillary climate variables, and albedo values derived from the literature. This research evaluates a series of methods used to calculate net radiation over different canopy surfaces. The four components of net radiation were measured at eight locations including urban, agricultural, rangeland, forest, wetland, and open water land types in central Florida. Data collected from January 2004 to December 2005 were used in this analysis. The results identify the most appropriate method to estimate net radiation and quantify net radiation and potential ET error estimates by method. Additionally, the impact of diurnal and seasonal albedo changes on net radiation calculations is examined. more...

[1] We present a conceptual synthesis of the impact that agricultural activity in India can have on land-atmosphere interactions through irrigation. We illustrate a ‘‘bottom up’’ approach to evaluate the effects of land use change on both physical processes and human vulnerability. We compared vapor fluxes (estimated evaporation and transpiration) from a pre-agricultural and a contemporary land cover and found that mean annual vapor fluxes have increased by 17% (340 km 3 ) with a 7% increase (117 km 3 ) in the wet season and a 55% increase (223 km 3 ) in the dry season. Two thirds of this increase was attributed to irrigation, with groundwater-based irrigation contributing 14% and 35% of the vapor fluxes in the wet and dry seasons, respectively. The area averaged change in latent heat flux across India was estimated to be 9 Wm 2 . The largest increases occurred where both cropland and irrigated lands were the predominant contemporary land uses. Citation: Douglas, E. M., D. Niyogi, S. Frolking, J. B. Yeluripati, R. A. Pielke Sr. more...

This study demonstrates the use of globally available Earth system science data sets for water assessment in otherwise information-poor regions of the world. Geospatial analysis at 8 km resolution shows that 64% of Africans rely on water resources that are limited and highly variable. Where available, river corridor flow is critical in augmenting local runoff, reducing impacts of climate variability, and improving access to freshwater. A significant fraction of cropland resides in Africa's driest regions, with 39% of the irrigation nonsustainable. Chronic overuse and water stress is high for 25% of the population with an additional 13% experiencing drought-related stress once each generation. Paradoxically, water stress for the vast majority of Africans typically remains low, reflecting poor water infrastructure and service, and low levels of use. Modest increases in water use could reduce constraints on economic development, pollution, and challenges to human health. Developing explicit geospatial indicators that link biogeophysical, socioeconomic, and engineering perspectives constitutes an important next step in global water assessment. more...

Conservation of high-biodiversity tropical forests is sometimes justified on the basis of assumed hydrological benefits - in particular, the reduction of flooding hazards for downstream floodplain populations. However, the"far-field"link between deforestation and distant flooding has been difficult to demonstrate empirically. This simulation study assesses the relationship between forest cover and hydrology for all river basins intersecting the world's tropical forest biomes. The study develops a consistent set of pan-tropical land cover maps gridded at one-half degree latitude and longitude. It integrates these data with existing global biogeophysical data. The study applies the Water Balance Model - a coarse-scale process-based hydrological model - to assess the impact of land cover changes on runoff. It quantifies the impacts of forest conversion on biodiversity and hydrology for two scenarios - historical forest conversion and the potential future conversion of the most threatened remaining tropical forests. A worst-case scenario of complete conversion of the most threatened of the remaining forested areas would mean the loss of another three million km2 of tropical forests. Increased annual yield from the conversion of threatened tropical forests would be less than 5 percent of contemporary yield in aggregate. However, about 100 million people - 80 million of them in floodplains - would experience increases of more than 25 percent in annual water flows. This might be associated with commensurate increases in peak flows, though further analysis would be necessary to gauge the impact on flooding. The study highlights basins in Southeast Asia, southern China, and Latin America that warrant further study. more...

Conservation of high-biodiversity tropical forests is sometimes justified on the basis of assumed hydrological benefits - in particular, reduction of flooding hazards for downstream floodplain populations. However, the 'far-field' link between deforestation and distant flooding has been difficult to demonstrate empirically. This simulation study assesses the relationship between forest cover and hydrology for all river basins intersecting the world's tropical forest biomes. The study develops a consistent set of pan-tropical land cover maps, gridded at one-half degree latitude and longitude. It integrates these data with existing global biogeophysical data. We apply the Water Balance Model - a coarse-scale process-based hydrological model - to assess the impact of land cover changes on runoff. We quantified these impacts of forest conversion on biodiversity and hydrology for two scenarios: historical forest conversion and the potential future conversion of the most threatened remaining tropical forests. A worst-case scenario of complete conversion of the most threatened of the remaining forested areas would mean the loss of another 3 million km2 of tropical forests. Increased annual yield from the conversion of threatened tropical forests would be less than 5% of contemporary yield in aggregate. However, about 100 million people - 80 million of them in floodplains - would experience increases of greater than 25% in annual water flows. This might be associated with commensurate increases in peak flows, though further analysis would be necessary to gauge the impact on flooding. We highlight basins in Southeast Asia, southern China, and Latin America that warrant further study. more...