Community Based Ecological Monitoring in Nova Scotia: Challenges and Opportunities

This article examines community-based ecological monitoring in Nova Scotia, with an emphasis on watershed stewardship groups. It discusses successes to date and future challenges, drawing on examples from the Atlantic Coastal Action Program (ACAP) and other community groups. The barriers to the generation of robust monitoring datasets and effective participation in watershed management are examined. The article concludes with a discussion of issues to be addressed to ensure that community groups can both gather scientifically valid ecological data and have meaningful input into the management of their local natural resources.     

A Fish-Based Index of Biotic Integrity to Assess Intermittent Headwater Streams in Wisconsin, USA

I developed a fish-based index of biotic integrity (IBI) to assess environmental quality in intermittent headwater streams in Wisconsin, USA. Backpack electrofishing and habitat surveys were conducted four times on 102 small (watershed area 1.7–41.5 km²), cool or warmwater (maximum daily mean water temperature ≥22 C), headwater streams in spring and late summer/fall 2000 and 2001. Despite seasonal and annual changes in stream flow and habitat volume, there were few significant temporal trends in fish attributes. Analysis of 36 least-impacted streams indicated that fish were too scarce to calculate an IBI at stations with watershed areas less than 4 km² or at stations with watershed areas from 4–10 km² if stream gradient exceeded 10 m/km (1% slope). For streams with sufficient fish, potential fish attributes (metrics) were not related to watershed size or gradient. Seven metrics distinguished among streams with low, agricultural, and urban human impacts: numbers of native, minnow (Cyprinidae), headwater-specialist, and intolerant (to environmental degradation) species; catches of all fish excluding species tolerant of environmental degradation and of brook stickleback (Culaea inconstans) per 100 m stream length; and percentage of total individuals with deformities, eroded fins, lesions, or tumors. These metrics were used in the final IBI, which ranged from 0 (worst) to 100 (best). The IBI accurately assessed the environmental quality of 16 randomly chosen streams not used in index development. Temporal variation in IBI scores in the absence of changes in environmental quality was not related to season, year, or type of human impact and was similar in magnitude to variation reported for other IBI's.     

典型喀斯特区侵蚀性降雨特征及坡面生物措施水土流失防控效应

降雨类型和生物措施是坡面水土流失的重要影响因素.为研究喀斯特区降雨类型和不同坡面生物措施共同作用下的水土保持效益,以贵州蚂蟥田小流域水土保持监测站2014—2018年5年的径流小区实测数据为基础,分析了112场次的侵蚀性降雨特征,并以降雨量、降雨历时、平均降雨强度为指标对其进行分类.同时,分析了不同侵蚀性降雨类型下6个...     

云南拉市海流域退耕还湿对农户的增收效应

基于云南拉市海流域2005～2016年的农户面板数据,采用双重差分法(DID)并借助PSM-DID、工具变量、安慰剂测试等多种稳健性检验工具,对退耕还湿的增收效应进行实证分析.研究发现,退耕还湿对农户增收具有显著的促进作用,使家庭总收入和人均收入分别提高了39.2％和43.5％,这一结论在进行多项稳健性检验后仍然成立;...     

Nutrients and Heavy Metals in Legacy Sediments: Concentrations,Comparisons with Upland Soils,and Implications for Water Quality

Concentrations of nutrients and heavy metals in streambank legacy sediments are needed to estimate watershed exports and to evaluate against upland inputs. Concentrations of nutrients and heavy metals were determined for legacy sediments in 15 streambanks across northeastern Maryland, southeastern Pennsylvania, and northern Delaware. Samples were collected from multiple bank depths from forested, agricultural, urban, and suburban sites. Analyses were performed for fine (<63 μm) and coarse sediment fractions. Nutrient and heavy metal concentrations were significantly higher in fine than coarse legacy sediments and water extractable nutrient concentrations were significantly greater for fine sediments. Nutrient and heavy metal concentrations were highest in streambank legacy sediments associated with urban land use, but few differences were found with bank depth. Total N (40–3,970 mg/kg) and P (25–1,293 mg/kg) and bioavailable P (0.25–48.8 mg/kg) concentrations for legacy sediments were lower than those for upland soils. This suggests that legacy sediments could serve as sink or source of N and P depending on the redox conditions and stream water nutrient concentrations. However, despite low concentrations, caution should be exercised since streambank erosion and legacy sediment mass loadings could be high, these sediments are in immediate proximity of aquatic ecosystems, and biogeochemical transformations could result in release of the nutrients.     

Assessing Impervious Surface Connectivity and Applications for Watershed Management1

Abstract: Although total impervious area (TIA) is often used as an indicator of urban disturbance, recent studies suggest that the subset of impervious surfaces that route stormwater runoff directly to streams via stormwater pipes, called directly connected impervious area (DCIA), may be a better predictor of stream ecosystem alteration. We evaluated the differences between TIA and DCIA in the Shepherd Creek catchment, a small (1.85‐km²), suburban basin in Cincinnati, Ohio. Imperviousness determinations were calculated based on publicly available geographic information system (GIS) data and parcel‐scale field assessments, and these direct assessments were compared to DCIA calculated from published, empirical relationships. Impervious and semi‐impervious area comprised 13.1% of the catchment area, with 56.3% of the impervious area connected. When summarized by subcatchments (0.26‐1.85 km²), TIA measured in the field (11‐23%) was considerably higher than that calculated from the National Land Cover Data Imperviousness Layer (7‐18%). In contrast, TIA calculated based on aerial photos was similar to TIA calculated from field assessments, thus indicating that photo interpretation may be adequate for catchment‐scale (>25 ha) TIA determinations. While these GIS data sources can be used to calculate TIA, on‐site assessments were necessary to accurately determine DCIA within residential parcels. There was a wide variation in percent connectivity across parcels, and, subsequently, DCIA was not accurately predicted from empirical relationships with TIA. We discuss applications of DCIA data that highlight the importance of parcel‐scale field assessments for managing suburban watersheds.     

Identification of Sediment Sources in Forested Watersheds With Surface Coal Mining Disturbance Using Carbon and Nitrogen Isotopes1

Abstract: Sediments and soils were analyzed using stable carbon and nitrogen isotope ratio mass spectrometry and carbon and nitrogen elemental analyses to evaluate the their ability to indicate land‐use and land management disturbance and pinpoint loading from sediment transport sources in forested watersheds disturbed by surface coal mining. Samples of transported sediment particulate organic matter were collected from four watersheds in the Southern Appalachian forest region of southeastern Kentucky. The four watersheds had different surface coal mining history that were classified as undisturbed, active mining, and reclaimed conditions. Soil samples were analyzed including reclaimed grassland soils, undisturbed forest soils, geogenic organic matter associated with coal fragments in mining spoil, and soil organic matter from un‐mined grassland soils. Statistically significant differences were found for all biogeochemical signatures when comparing transported sediments from undisturbed watersheds and surface coal mining disturbed watersheds, and the results were attributed to differences in erosion sources and the presence of geogenic organic matter. Sediment transport sources in the surface coal mining watersheds were analyzed using Monte Carlo mass balance un‐mixing and it was found that: δ¹⁵N showed the ability to differentiate streambank erosion and surface soil erosion; and δ¹³C showed the ability to differentiate soil organic matter and geogenic organic matter. Results from the analyses suggest that streambank erosion downstream of surface coal mining sites is an especially significant source of sediment in coal mining disturbed watersheds. Further, the results suggest that the sediment transport processes governing streambank erosion loads are taking longer to reach geomorphologic equilibrium in the watershed as compared with the surface erosion processes. The dual‐isotope technique provides a useful method for further investigation of the impact of surface coal mining in the uplands of the watershed upon the geomorphologic state of the channel and the source of organic matter in aquatic systems impacted by surface coal mining.     

Evaluating Pre‐ and Post‐Fire Peak Discharge Predictions across Western U.S. Watersheds

This study reviews five models commonly used in post‐fire hydrologic assessments: the Rowe Countryman and Storey (RCS), United States Geological Survey (USGS) Linear Regression Equations, USDA Windows Technical Release 55 (USDA TR‐55), Wildcat5, and U.S. Army Corps of Engineers (USACE) Hydrologic Modeling System (HEC‐HMS). The models are applied to eight diverse basins in the western United States (U.S.) (Arizona, California, Colorado, Montana, and Washington) affected by wildfires and assessed by input parameters, calibration methods, model constraints, and performance. No one model is versatile enough for application to all study sites. Results show inconsistency between model predictions for events across the sites and less confidence with larger return periods (25‐ and 50‐year events) and post‐fire predictions. The RCS method performs well, but application is limited to southern California. The USGS linear regression model has wider regional application, but performance is less reliable at the large recurrence intervals and post‐fire predictions are reliant on a subjective modifier. Of the three curve number‐based models, Wildcat5 performs best overall without calibration, whereas the calibrated TR‐55 and HEC‐HMS models show significant improvement in pre‐fire predictions. Results from our study provide information and guidance to ultimately improve model selection for post‐fire prediction and encourage uniform parameter acquisition and calibration across the western U.S.     

日本琵琶湖流域污水超深度处理及污泥处置

以日本琵琶湖流域东北部净化中心为例,介绍了日本琵琶湖流域市政污水处理概况,重点阐述了以投加絮凝剂的多段硝化脱氮法为核心生物工艺的"超深度"处理技术和以"焚烧—熔融"为核心工艺的污泥资源化处置技术,为我国市政污水的深度处理和污泥处置提供了技术和发展借鉴。     

Multicriteria Evaluation of Water Resources Sustainability in the Context of Watershed Management1

Kang, Min‐Goo and Gwang‐Man Lee, 2011. Multicriteria Evaluation of Water Resources Sustainability in the Context of Watershed Management. Journal of the American Water Resources Association (JAWRA) 47(4):813‐827. DOI: 10.1111/j.1752‐1688.2011.00559.x Abstract: To evaluate water resources sustainability at the watershed scale within a river basin’s context, the Water Resources Sustainability Evaluation Model is developed. The model employs 4 criteria (economic efficiency, social equity, environmental conservation, and maintenance capacity) and has 16 indicators, integrating them using their relative weights. The model is applied to evaluate the water resources sustainability of watersheds in the Geum River basin, South Korea. A geographic information system is employed to efficiently build a database for the indicators, and the values of the indicators are normalized using the probability distribution functions fitted to the datasets of the indicators. The evaluation results show that, overall, the water resources sustainability of the watersheds in the upper basin is better than other areas due to the good environmental conditions and the dam management policies of South Korea. The analysis of the correlations among the model’s components and the comparison between the results of the model and the Water Poverty Index show that the model can provide reasonable evaluation results for the water resources sustainability of watersheds. Consequently, it is concluded that the model can be an effective tool for evaluating the states of water resource management from the perspective of sustainable development and provide a basis on which to create policies for improving any inadequacies in watersheds.