The Soil Conservation Service (SCS) Curve Number (CN) method is a widely used model developed by the Natural Resources Conservation Service (NRCS) that estimates the surface runoff generated from a land area using factors such as land cover, soil type, and precipitation depth. However, this empirical model was developed over 60 years ago with limited data; thus, NRCS proposed revising the method with support of an ASCE-ASABE task group. The proposed revisions include updating the initial abstraction estimation in the CN equation and modifying the curve number for all land use and soil hydrologic group combinations. The proposed revisions are expected to improve the hydrologic response estimation, especially for smaller precipitation events. Since surface runoff is the driving force that transports sediment, nutrients, and other chemicals in natural systems, this study aims to understand how predicted ecohydrological indicators vary between the original and the proposed revised versions of the SCS Curve Number method using the Soil and Water Assessment Tool (SWAT). Additionally, a small case study site was selected to understand how the revisions alter design storm runoff analysis. The Spring Creek watershed, located in central Pennsylvania, was selected as the study watershed for the SWAT simulation since it contains a mixture of forested, agricultural, and urban land covers. Results from the simulation study indicate a 5-13% increase in annual runoff predictions with the revised equation compared to the original equation. Though most average monthly runoff depths increased by 8-25% using the revised equation, winter months generally simulated runoff depths that were 1-5% lower than the original equation. Average daily nutrient loadings in the streamflow at the watershed outlet increased by 9-16% and 3-10% for nitrate and mineral phosphorus loadings, respectively. When using the revised equation, the average daily erosion and sediment loading in the streamflow was consistently within 1% of the original equation. The SWAT simulation results suggest that current agricultural and urban best management practices (BMPs) will experience higher runoff volumes on a yearly time scale, while the small-scale case study results suggest that urban BMPs can be designed to be smaller in size if rural lands are urbanized. More detailed evaluations of the proposed SCS curve number method are required on water quality simulations, stormwater management, and BMP designs.

Agricultural Best Management Practices (BMPs) have been employed for years as erosion reduction measures on cultivated lands. The ability to model the effects of BMPs at the watershed scale using a standardized process-based method provides watershed managers with an important decision making tool for addressing large-scale water quality concerns. This study uses a process-based BMP simulation method with the Soil and Water Assessment Tool (SWAT) to evaluate five BMPs including grassed waterways, channel stabilization structures, strip crops, cover crops and vegetative filter strips on almond orchards in northern California, USA. The sediment reduction rate of the five BMPs was compared to a base case where no BMPs were applied to the watershed and analyzed for several precipitation scenarios to compare BMP effectiveness. In-channel BMPs which included grassed waterways and channel stabilization structures, reduced sediment load at the watershed outlet by 8% to 14%, respectively, depending on the annual precipitation scenario. Grassed waterways consistently outperformed channel stabilization structures, reducing sediment load by an additional 2% to 5% compared to channel stabilization structures. Upland BMPs including strip crops, cover crops and vegetative filter strips reduced sediment yield by 15 to 100% for the various precipitation scenarios. For years with median and above median precipitation, strip crops were most effective, reducing sediment yield by 63% in both cases, whereas cover crops only reduced sediment yield by 54% and 15%, respectively. For the below median precipitation year, the cover crop reduced sediment yield from fields completely (100%), whereas strip crops and vegetative filter strips only reduced sediment load by 64% and 59%, respectively. For all BMPs, a positive correlation between sediment load/yield and increasing precipitation amount and intensity was observed. The methods presented in this study are easily applicable to watershed scale studies of other basins and for other water quality concerns, such as the fate and transport of agricultural pesticides and nutrients.

This book gathers the latest advances, innovations, and applications in the field of innovative biosystems engineering for sustainable agriculture, forestry and food production. Focusing on the challenges of implementing sustainability in various contexts in the fields of biosystems engineering, it shows how the research has addressed the sustainable use of renewable and non-renewable resources. It also presents possible solutions to help achieve sustainable production. The Mid-Term Conference of the Italian Association of Agricultural Engineering (AIIA) is part of a series of conferences, seminars and meetings that the AIIA organizes, together with other public and private stakeholders, to promote the creation and dissemination of new knowledge in the sector. The contributions included in the book were selected by means of a rigorous peer-review process, and offer an extensive and multidisciplinary overview of interesting solutions in the field of innovative biosystems engineering for sustainable agriculture.

This proceedings volume contains papers and extended abstracts presented at the International Conference on Sustainable Watershed Management (SuWaMa 2014). The Conference was the second in a series of Sustainable Watershed Management Conferences. The objective of the Conference Series was to present and discuss advanced environmental models and contemporary decision support tools for the sustainable use and development of watersheds. Contributions cover the following topics: sound watershed management practices (case studies and examples from various countries including lessons learned from implementation of both successful and deficient management scenarios), decision support tools (such as monitoring, GIS, ecological economics, cost/benefit analysis and decision making models), integrated environmental model applications for management (including watershed, air-shed, coastal, and living resource models), trans-boundary environmental issues (air pollution, climate change, coastal oceans at regional, continental, and global scales) and global watershed sustainability. This multidisciplinary volume will benefit natural and social scientists, engineers, managers and other professionals as well as stakeholders with an interest in water resources and their management.

The latest book in the popular series demonstrates state-of-the-art methods, models, and techniques for water quality management. This book includes a CD-ROM that collects hundreds of hard-to-find literature citations from the gray literature.

This book presents recent lessons learned in the context of research and development for various dryland ecosystems, focusing on water resources management, land and vegetation cover degradation and remediation, and socioeconomic aspects, as well as integrated approaches to ensuring water and land security in view of the current and predicted climate change. As water and land are the essential bases of food production, the management of these natural resources is becoming a cornerstone for the development of dryland populations. The book gathers the peer-reviewed, revised versions of the most outstanding papers on these topics presented at the ILDAC2015 Conference in Djerba, Tunisia.