STORM RUNOFF PREDICTION BASED ON A SPATIALLY DISTRIBUTED TRAVEL TIME METHOD UTILIZING REMOTE SENSING AND GIS1

ABSTRACT: In this study, remotely sensed data and geographic information system (GIS) tools were used to estimate storm runoff response for Simms Creek watershed in the Etonia basin in northeast Florida. Land cover information from digital orthophoto quarter quadrangles (DOQQ), and enhanced thematic mapper plus (ETM+) were analyzed for the years 1990, 1995, and 2000. The corresponding infiltration excess runoff response of the study area was estimated using the U.S. Department of Agriculture (USDA), Natural Resources Conservation Service Curve Number (NRCS‐CN) method. A digital elevation model (DEM)/GIS technique was developed to predict stream response to runoff events based on the travel time from each grid cell to the watershed outlet. A comparison of predicted to observed stream response shows that the model predicts the total runoff volume with an efficiency of 0.98, the peak flow rate at an efficiency of 0.85, and the full direct runoff hydrograph with an average efficiency of 0.65. The DEM/GIS travel time model can be used to predict the runoff response of ungaged watersheds and is useful for predicting runoff hydrographs resulting from proposed large scale changes in the land use.     

MAPPING HYDROLOGIC UNITS FOR THE NATIONAL WATERSHED BOUNDARY DATASET1

ABSTRACT: In 2002, Wyoming became the first state to complete development of a statewide 1:24,000‐scale Watershed Boundary Dataset (WBD) under the new Federal Standards for Delineation of Hydrologic Unit Boundaries. The product was developed through the coordinated efforts of numerous state, federal, and local entities both within Wyoming and in neighboring states. Development of a comprehensive, standardized hydrologic unit boundary dataset in a “headwaters” state such as Wyoming poses a number of unique challenges. This paper details the WBD's development in Wyoming, highlighting technical methodology development and interagency coordination strategies. Evolution of the WBD standard is reviewed, addressing inconsistencies between definitions for hydro‐logic units and “true” watershed delineations. While automated methods are improving, manual and semi‐automated techniques continue to serve as valuable approaches to hydrologic unit boundary delineation given the quality of digital terrain models and the multijurisdictional nature of watershed based management. This case study provides insight on future development and maintenance of the WBD within and across other states and regions of the country and on opportunities for linking the WBD to related water resource geospatial data products like the National Hydrography Dataset.     

ESTIMATING THE DEMAND FOR IRRIGATION WATER IN THE CENTRAL VALLEY OF CALIFORNIA1

ABSTRACT: This paper computes estimates of the demand for surface irrigation water directly from disaggregated profit functions for fields in the San Joaquin Valley of California. It finds that treating delivered surface water and pumped ground water as separate, imperfectly substitutable inputs to production matters a great deal. We find substantial ranges of inelastic demand for delivered water, and thresholds across which demand then becomes highly elastic. The results imply that moves toward freer water markets could lead to large quantities reallocated from agriculture to urban uses in the Western U.S., but would require large price increases and would induce extensive ground water mining and major changes in cropping patterns. While these results are dependent on our particular model and simplifying assumptions, evidence exists that they may be robust.     

A Critical Review of Citizens' Juries: How Useful are they in Facilitating Public Participation in the EU Water Framework Directive?

Citizens' juries (CJs) are recommended as one approach that might be used to encourage the active involvement of interested parties in the implementation of the EU Water Framework Directive (WFD). In this light the paper critically reviews the citizens' jury method in the context of water resource management. It examines three strategic challenges of representation, accountability and the role of experts, and issues of scale related to geography, institutions and time. Innovative adaptations of the CJ approach and other deliberative methods are explored as means to address these challenges. The review concludes by arguing that CJs will only be suitable for use in implementation of the WFD if such adaptations are further developed and used to tailor the CJ approach to the particular needs of water resource management in different circumstances.     

Management strategy impacts on ammonia volatilization from swine manure

Ammonia emitted from manure can have detrimental effects on health, environmental quality, and fertilizer value. The objective of this study was to measure the potential for reduction in ammonia volatilization from swine (Sus scrofa domestica) manure by temperature control, stirring, addition of nitrogen binder (Mohave yucca, Yucca schidigera Roezl ex Ortgies) or urease inhibitor [N-(n-butyl) thiophosphoric triamide (NBPT)], segregation of urine from feces, and pH modification. Swine manure [total solids (TS) = 7.6-11.2%, total Kjeldahl nitrogen (TKN) = 3.3-6.2 g/L, ammonium nitrogen NH(+)(4)-N = 1.0-3.3 g/L] was stored for 24, 48, 72, or 96 h in 2-L polyvinyl chloride vessels. The manure was analyzed to determine pre- and post-storage concentrations of TS and volatile solids (VS), TKN, and NH(+)(4)-N. The concentration of accumulated ammonia N in the vessel headspace (HSAN), post-storage, was measured using grab sample tubes. Headspace NH(3) concentrations were reduced 99.3% by segregation of urine from feces (P < 0.0001). Stirring and NBPT (152 microL/L) increased HSAN concentration (119 and 140%, respectively). Headspace NH(3) concentration increased by 2.7 mg/m(3) for every 1 degree C increase in temperature over 35 degrees C. Slurry NH(+)(4)-N concentrations were reduced by segregation (78.3%) and acidification to pH 5.3 (9.4%), and increased with stirring (4.8%) and increasing temperature (0.06 g/L per 1 degree C increase in temperature over 35 degrees C). Temperature control, urine-feces segregation, and acidification of swine manure are strategies with potential to reduce or slow NH(+)(4)-N formation and NH(3) volatilization.     

When context matters: a multilevel analysis of household and neighbourhood crowding on aggression and withdrawal

Studies examining the effects of density and crowding on human social behaviour have produced inconsistent results. This paper argues that among the reasons for these varied findings are: (1) the failure of researchers to examine how the level of density in the wider contextual environment influences the nature of the relationship between household density and social behaviour; (2) the tendency of past studies to overlook the negative consequences of both very low and very high levels of density; and (3) a lack of research investigating whether multiple coping strategies to high-density environments may be invoked by a single individual. Data from the Toronto Mental Health and Stress study are analysed using hierarchical nonlinear modelling to assess the interaction between household and neighbourhood density effects on aggression and withdrawal. The results support the notion that the effects of density on aggressive and withdrawn behaviour are nonlinear in nature and that the impact of household density is conditional on neighbourhood density. The implications of these findings for future research on density are discussed.     

Compost amendment of Cu-Zn minespoil reduces toxic bioavailable heavy metal concentrations and promotes establishment and biomass production of Bromus carinatus (Hook and Arn.)

A series of lab and greenhouse studies were undertaken to understand how Cu and Zn toxicity influences Bromus carinatus (Hook and Arn.) growth, to what degree an organic amendment (yard waste compost) may reduce Cu and Zn bioavailability in Cu-Zn minespoil and promote plant growth in combination with fertilizer, and how the vertical distribution of compost in the minespoil influences rooting depth. Root Cu and Zn toxicity thresholds were determined to be 1 mgL(-1) and 10 mgL(-1) in solution, respectively. The compost amendment had exceptionally high Cu and Zn binding capacities (0.17 and 0.08 g metal g C(-1), for Cu and Zn, respectively) that were attributed to high compost humic and fulvic acid concentrations. Maximum plant biomass was achieved when minespoil was amended with compost and fertilizer in combination. Fertilizer alone had no effect on plant growth. Mixing compost into the minespoil was essential to promote adequate rooting depth.     

Network structure and adaptive capacity in watershed governance

What supports the adaptive capacity of watershed governance? Using document review, interviews, and network diagrams, we analyze how structural attributes of a governance network emerged and co-evolved with changes in biophysical conditions in a case study of a small watershed in northeast Ohio. Results indicate that the network governance structure that emerged evolved to become a hybrid of two different structural forms that diversified stakeholder engagement, generated social capital, improved social learning, and stimulated change in management practices, all of which have enhanced adaptive capacity. A significant challenge to adaptive capacity arises, however, as network governance has come to rely significantly on a centralized organization to broker relationships for information and other resources.     

Phosphorus losses from monitored fields with conservation practices in the Lake Erie Basin,USA

Conservation practices are implemented on farm fields in the USA through Farm Bill programs; however, there is a need for greater verification that these practices provide environmental benefits (e.g., water quality). This study was conducted to assess the impact of Farm Bill eligible conservation practices on soluble P (SP) and total P (TP) losses from four fields that were monitored between 2004 and 2013. No-tillage doubled SP loading compared to rotational tillage (e.g., tilled only before planting corn); however, no-tillage decreased TP loading by 69 % compared to rotational tillage. Similarly, grassed waterways were shown to increase SP loads, but not TP loads. A corn–soybean–wheat–oat rotation reduced SP loads by 85 % and TP loads by 83 % compared to the standard corn–soybean rotation in the region. We can potentially attain TP water quality goals using these Farm Bill practices; however, additional strategies must be employed to meet these goals for SP.