Effects of Land Use Data on Dry Deposition in a Regional Photochemical Model for Eastern Texas

ABSTRACT

Land use data are among the inputs used to determine dry deposition velocities for photochemical grid models such as the Comprehensive Air Quality Model with extensions (CAMx) that is currently used for attainment demonstrations and air quality planning by the state of Texas. The sensitivity of dry deposition and O₃ mixing ratios to land use classification was investigated by comparing predictions based on default U.S. Geological Survey (USGS) land use data to predictions based on recently compiled land use data that were collected to improve biogenic emissions estimates. Dry deposition of O₃ decreased throughout much of eastern Texas, especially in urban areas, with the new land use data. Predicted 1-hr averaged O₃ mixing ratios with the new land use data were as much as 11 ppbv greater and 6 ppbv less than predictions based on USGS land use data during the late afternoon. In addition, the area with peak O₃ mixing ratios in excess of 100 ppbv increased significantly in urban areas when deposition velocities were calculated based on the new land use data. Finally, more detailed data on land use within urban areas resulted in peak changes in O₃ mixing ratios of ~2 ppbv. These results indicate the importance of establishing accurate, internally consistent land use data for photochemical modeling in urban areas in Texas. They also indicate the need for field validation of deposition rates in areas experiencing changing land use patterns, such as during urban reforestation programs or residential and commercial development.     

Complementing institutional with localised strategies for climate change adaptation: a South-North comparison

Climate change and disasters pose a serious risk to sustainable development. In the South, local coping strategies are an important element of adaptation to climate and disaster risk. Such strategies have emerged because of the limited assistance provided by urban actors and associated social security and governance systems. In the North, in contrast, local coping strategies are comparatively poorly developed. However, the extent of the changing climatic conditions is also reducing the capacity of Northern institutions to deal with climatic extremes and variability, which emphasises the need for more local-level engagement in the North. This paper analyses the differences in local and institutional responses to climate change and disasters in a Southern and a Northern city (San Salvador, El Salvador, and Manchester, United Kingdom, respectively), and highlights how the lessons learned might be translated into an improved distributed governance system; that is, an 'integrated engagement model', where local and institutionalised responses support rather than hinder each other, as is currently the case.     

A Systemic Approach to Scoping of Factors Influencing More Sustainable Land Use in Herefordshire

Abstract

Defining and putting into practice sustainable land use is a complex, systemic problem. Systems models and techniques were used in a study of Herefordshire to clarify the situation and identify the potential for a more locally focused, learning-based approach to land use. Issues included: (i) uncertainty about the boundary of a ‘system of sustainable Herefordshire land use’; (ii) the complexity of economic flows in the county and the absence of some critical data; (iii) the importance of the Herefordshire landscape to tourism and the role of agriculture as a determinant of the state of that landscape; (iv) weakness of the institutional linkage between tourism and agriculture; (v) the current lack of inclusion of many relevant stakeholders in concerted action. Factors favouring a learning approach included a strong local identity, local food-related developments, and educational initiatives. Barriers to such an approach included questions of power and landholding, government policies, and attitudes and skills within organizations. These findings are considered in relation to the wider debate over approaches to sustainability.     

I-C-SEA Change: A participatory tool for rapid assessment of vulnerability of tropical coastal communities to climate change impacts

We present a synoptic, participatory vulnerability assessment tool to help identify the likely impacts of climate change and human activity in coastal areas and begin discussions among stakeholders on the coping and adaptation measures necessary to minimize these impacts. Vulnerability assessment tools are most needed in the tropical Indo-Pacific, where burgeoning populations and inequitable economic growth place even greater burdens on natural resources and support ecosystems. The Integrated Coastal Sensitivity, Exposure, and Adaptive Capacity for Climate Change (I-C-SEA Change) tool is built around a series of scoring rubrics to guide non-specialists in assigning scores to the sensitivity and adaptive capacity components of vulnerability, particularly for coral reef, seagrass, and mangrove habitats, along with fisheries and coastal integrity. These scores are then weighed against threat or exposure to climate-related impacts such as marine flooding and erosion. The tool provides opportunities for learning by engaging more stakeholders in participatory planning and group decision-making. It also allows for information to be collated and processed during a “town-hall” meeting, facilitating further discussion, data validation, and even interactive scenario building.

Electronic supplementary material

The online version of this article (doi:10.1007/s13280-015-0652-x) contains supplementary material, which is available to authorized users.     

A Laboratory Assessment of an Innovative Technology for the Detection of DNAPLs

A promising new technology for the detection of dense nonaqueous phase liquids, or DNAPLs, is cosolvent injection/extraction. Cosolvents, such as alcohols, are injected into the subsurface and interact with DNAPLs to increase their aqueous solubility, which increases recovery of the chemicals. A laboratory assessment was performed to determine if incorporating this technology with cone penetrometers could provide a useful sampling tool for DNAPL detection. A cone penetrometer was modeled in the laboratory by injecting and extracting small quantities of ethanol and propylene glycol at low concentrations into a homogeneous sand reactor contaminated with a residual saturation of tetrachloroethene (PCE). Experimental test results show that this technology is extremely sensitive to the vertical placement of the sampler, but is capable of enhancing PCE solubility while recovering most of the alcohol injected. Field testing of this technology will provide the next step in determining the feasibility of this technology for DNAPL detection.     

Ecological Integrity Assessment of Lakes Using Fish Communities: An Example from Traunsee Exposed to Intensive Fishing and to Effluents from the Soda Industry

In order to analyse potential influences of soda industryeffluents on the ecological integrity of Traunsee (TS) weinvestigated the fish community of the lake in comparison witha reference lake (Hallstättersee HS) and used a reconstructionfrom the (older) literature concerning the original speciescomposition of Traunsee. Published `Index of Biotic Integrity(IBI)' metrics were considered to be of limited value due tothe relatively low species number in the oligotrophic, Alpinelake. Therefore we included, in addition to speciescomposition, studies on egg distribution, larval fishdensities, life-history parameters (i.e. growth, maturity,fecundity, age and size composition), stress levels and heavymetal content of the dominant whitefish (Coregonuslavaretus), as well as overall fish density and biomass (usinghydroacoustics) to assess the ecological status of the fishcommunity. Two of the original 18 species have disappearedfrom the lake, presumably in connection with the introductionof non-native eel (Anguilla anguilla) and theconstruction of a power plant in the outflow. Silt from grindedlimestone together with highly alkaline pore waters is emittedvia industrial wastewater from Sodaworks and covers part of thelake bottom. We observed that eggs of whitefish were spawnedmainly in the main inflowing river and close to the shore, thusavoiding the silty areas and making the anticipated damage tothe reproductive potential of whitefish neglectable. This wascorroborated by larval surveys done weekly on both lakes fromJanuary to May, which showed halve the density of whitefishlarvae in TS compared to HS. Estimates of potentially spawningfish from hydroacoustic surveys resulted in a ratio of 1(TS) :3 (HS). Analysis of whitefish revealed that they are growingfaster in TS and have higher fecundity leading to somecompensation of lower abundance. High levels of fishing in TSmight have led to this pattern and to depressed yields asindicated by the age composition. Level of oxidative stress andheavy metal content were not discernible from the referencelake. Therefore we concluded that negative impacts on theecological status of the fish community resulted from fisheriesmismanagement and a power plant situated in the outflow of thelake, considered to have damaged spawning places for somespecies, but not from soda industry effluents.     

Predicting streamflow response to fire-induced landcover change: implications of parameter uncertainty in the MIKE SHE model

Fire is a primary agent of landcover transformation in California semi-arid shrubland watersheds, however few studies have examined the impacts of fire and post-fire succession on streamflow dynamics in these basins. While it may seem intuitive that larger fires will have a greater impact on streamflow response than smaller fires in these watersheds, the nature of these relationships has not been determined. The effects of fire size on seasonal and annual streamflow responses were investigated for a medium-sized basin in central California using a modified version of the MIKE SHE model which had been previously calibrated and tested for this watershed using the Generalized Likelihood Uncertainty Estimation methodology. Model simulations were made for two contrasting periods, wet and dry, in order to assess whether fire size effects varied with weather regime. Results indicated that seasonal and annual streamflow response increased nearly linearly with fire size in a given year under both regimes. Annual flow response was generally higher in wetter years for both weather regimes, however a clear trend was confounded by the effect of stand age. These results expand our understanding of the effects of fire size on hydrologic response in chaparral watersheds, but it is important to note that the majority of model predictions were largely indistinguishable from the predictive uncertainty associated with the calibrated model - a key finding that highlights the importance of analyzing hydrologic predictions for altered landcover conditions in the context of model uncertainty. Future work is needed to examine how alternative decisions (e.g., different likelihood measures) may influence GLUE-based MIKE SHE streamflow predictions following different size fires, and how the effect of fire size on streamflow varies with other factors such as fire location.     

Sorption of atmospheric ammonia by soil and perennial grass downwind from two large cattle feedlots

Livestock manure in feedlots releases ammonia (NH3), which can be sorbed by nearby soil and plants. Ammonia sorption by soil and its effects on soil and perennial grass N contents downwind from two large cattle feedlots in Alberta, Canada were investigated from June to October 2002. Atmospheric NH3 sorption was measured weekly by exposing air-dried soil at sampling points downwind along 1700-m transects. The amount of NH3 sorbed by soil was 2.60 to 3.16 kg N ha(-1) wk(-1) near the source, declining to about 0.25 kg N ha(-1) wk(-1) 1700 m downwind, reflecting diminishing atmospheric NH3 concentrations. Ammonia sorption at a control site away from NH3 sources was much lower: 0.085 kg N ha(-1) wk(-1). Based on these rates, about 19% of emitted NH3 is sorbed by soil within 1700 m downwind of feedlots. Field soil and grass samples from the transect lines were analyzed for total N (TN) and KCl-extractable N content (soil only). Nitrate N content in field soil followed a trend similar to that of atmospheric NH3 sorption. Soil TN contents, because of high background levels, showed no clear pattern. The TN content of grass, downwind of the newer feedlot, followed a pattern similar to that of NH3 sorption; downwind of the older feedlot, grass TN was correlated to soil TN. Our results suggest that atmospheric NH3 from livestock operations can contribute N to local soil and vegetation, and may need to be considered when determining fertilizer rates and assessing environmental impact.     

DEBRIS FLOWS THROUGH DIFFERENT FOREST AGE CLASSES IN THE CENTRAL OREGON COAST RANGE1

ABSTRACT: Debris flows in the Pacific Northwest can play a major role in routing sediment and wood stored on hillslopes and in first‐through third‐order channels and delivering it to higher‐order channels. Field surveys following a large regional storm event investigated 53 debris flows in the central Oregon Coast Range to determine relationships among debris flow characteristics and the age class of the surrounding forest. The volume of sediment and wood delivered by debris flows was strongly correlated with runout length. Debris flows that initiated at roads were significantly longer than nonroad related failures, and road related landslides were an order of magnitude larger than nonroad related landslides. Clearcuts and roads tended to have more numerous contributing landslides relative to second growth and mature forests. No statistically significant difference in the average debris flow runout length was detected among the forest age classes, although debris flows initiating in clearcuts and mixed forest and at roads occasionally supported extremely long runout lengths that were outside the range of variability observed in completely forested basins. The size of wood in deposits was not correlated with the size of trees on the adjacent slopes, suggesting that the majority of wood in debris flow deposits was from remobilization of wood previously stored in low order channels.     

Polycyclic aromatic hydrocarbons and hydroxylated metabolites in the muscle tissue of Eurasian perch (Perca fluviatilis) through dietary exposure during a 56-day period

Eurasian perch (Perca fluviatilis) was exposed trophically to phenanthrene, pyrene and benzo[a]pyrene. Accumulation kinetics in the muscle tissue of parent PAHs and hydroxylated metabolites were established for 56 days at 3 levels of exposure (0, 100 and 500 μg/kg BW). Benzo[a]pyrene and 3-hydroxy-benzo[a]pyrene were not detected in the muscles. During exposure, there was an increase in phenanthrene, pyrene and their hydroxylated metabolites in the muscle tissue. Low transfer to muscle tissue was observed at equilibrium for phenanthrene (4.4 ± 0.6% and 2.7 ± 0.8%) and pyrene (1.0 ± 0.2% and 0.33 ± 0.09%), depending on the concentrations in the spiked feed.