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Summary: Alpine meadows in the upper catchments of the Yangtze River, China provide critical amounts of water to maintain regional water resources, but little is known about the hydrological processes in these alpine ecosystems. In this paper, we analyzed the sources of precipitation in an alpine meadow using the deuterium excess in rain, fog, soil water, shallow groundwater and stream water. Rain and fog in the alpine meadow had high deuterium excess, 35‰ and 38‰ compared to 10‰ of precipitation brought by monsoon at lower elevation. These high values suggested that a large part of rain at the alpine meadow derived from secondarily evaporated water and that fog derived from the evaporated water produced shortly after rain events. However, averaged evaporation rate calculated by an isotopic mass balance model of soil water was only 0.26mm/d, about 3.6% of the rainfall and 7.57‰ of the average deuterium excess value of rain. The contribution from evaporated water to precipitation in the alpine meadow therefore had to be mainly from sub-alpine vegetations in the region. This eco-hydrological relation between sub-alpine and alpine ecosystems can partly explain the high water yield of the alpine meadow and should be considered for regional resource management. [Copyright &y& Elsevier]

It has been observed that the distance between the outlets of transverse basins in orogens is typically half of the distance between the main divide and the range front irrespective of mountain range size or erosional controls. Although it has been suggested that this relationship is the inherent expression of Hack's law, and/or possibly a function of range widening, there are cases of notable deviations from the typical half-width average spacing. Moreover, it has not been demonstrated that this general relationship is also true for basins in morphologically similar nonorogenic settings, or for those that do not extend to the main drainage divide. These issues are explored by investigating the relationship between basin outlet spacing and the 2-dimensional geometric properties of drainage basins (basin length, main valley length and basin area) in order to assess whether the basin outlet spacing-range width ratio is a universal characteristic of fluvial systems. We examined basins spanning two orders of magnitude in area along the southern flank of the Himalayas and the coastal zone of southeast Africa. We found that the spacing between basin outlets ( Los) for major transverse basins that drain the main divide (range-scale basins) is approximately half of the basin length ( Lb) for all basins, irrespective of size, in southeast Africa. In the Himalayas, while this ratio was observed for eastern Himalayan basins (a region where the maximum elevations coincided with the main drainage divide), it was only observed in basins shorter than ∼30 km in the western and central Himalayas. Our analysis indicates that basin outlet spacing is consistent with Hack's law, apparently because the increase in basin width (represented by outlet spacing) with basin area occurs at a rate similar to the increase in main stream length ( Lv) with basin area. It is suggested that most river systems tend towards an approximately diamond-shaped packing arrangement, and this applies both to the nonorogenic setting of southeast Africa as well as most orogenic settings. However, in the western Himalayas shortening associated with localised rock uplift appears to have occurred at length scales smaller than most the basins examined. As a result rivers in basins longer than ∼30 km have been unable to erode in a direction normal to the range front at a sufficiently high rate to sustain this form and have been forced into an alternative, and possibly unstable, packing arrangement. [ABSTRACT FROM AUTHOR]

Summary: Predicting groundwater supply for an entire watershed in mountainous terrain required an approach that considered a wide range in data availability between valley bottom and headwater areas, large change in elevation, and steep topography. The methodology utilized the MIKE-SHE numerical code to simulate overland flow, actual evapotranspiration and recharge for data-rich areas, and a simpler, seasonal water budget for data-limited areas. Recharge estimates were combined to form spatially variable recharge boundary conditions for a larger-scale groundwater flow model of the entire mountainous watershed. Research focused on the BX Creek watershed, located in the north Okanagan Basin in British Columbia, one of Canada’s fastest growing and most water-limited regions. Groundwater recharge was found to vary from 0 to 20mm/yr at lower elevations, and from 20 to 50mm/yr at higher elevations. Simulation of the whole flow system illustrated that 58% of the groundwater flux from upland areas occurs through a relatively narrow alluvial fan aquifer that extends to the valley bottom, and the remaining recharge is nearly equally divided between groundwater flow through the mountain block (20%) and direct recharge (22%). Geochemical data from domestic water wells within the watershed suggest that water in the alluvial aquifer and bedrock are generally similar (i.e., common origin); however, stable isotope data indicate that groundwater in the alluvial aquifer may be derived from snowmelt recharge at a different time and elevation than snowmelt recharge to the bedrock. The combination of modelling results and complimentary geochemical and isotopic analyses of surface water and groundwater, provide an adequate first-order approximation of groundwater flow in the watershed. [Copyright &y& Elsevier]

• The maximum contribution ratio of snowmelt water to runoff was 59.8% higher than inland mountainous areas in Erdaobaihe River Watershed. • The response of water supply to climate change in semi-humid areas was very significant. • Snowmelt waterwill affect the balance of local water resources under the scenarios of global warming. Snow is an important form of water storage which profoundly affects the hydrological processes in alpine watersheds, especially the runoff during snowmelt period. As the strong impact of climate change, the concern about snowmelt water to runoff in alpine watersheds is dramatically growing. However, the studies are mainly focused on arid and semi-arid areas, the research on semi-humid regions sensitive to the climate change need to be strengthened. In this study, for evaluating the contribution of snowmelt water to runoff in snowmelt period, we calculated the stable isotope values (δD, δ18O and d -excess) of different water bodies including river, snow, rain, groundwater, and snowmelt water in the Erdaobaihe River watershed of Changbai Mountains area. The results indicated that the δ18O values of snowmelt water showed an increasing trend with increasing temperature, while the d-excess values of snowmelt water showed a decreasing trend. During the snowmelt period, the snow cover ratio varied from 20.31% to 0.02%. The contribution ratio of snowmelt water to runoff was from 14.4% to 59.8% with average of 42.60% and the total contribution discharge was about 36.56 × 106 m3, which was higher than inland mountainous areas as different elevation and climate. As the stable water source of river, the groundwater contributed 19.2–61.6% with average of 43.88%. The snowmelt water plays an important role in regional water balance. Owing to climate change, the snowfall period in Changbai Mountains was gradually shortening and extreme snowfall events were increasing. The results will provide evidence for further hydrological studies and help to plan future water management strategies in the alpine watershed. [ABSTRACT FROM AUTHOR]

The article presents the findings from a study that compares the alpine watershed characteristics in the Canadian Rocky Mountains based on data obtained from three digital elevation models (DEMs). The terrain topological information resources are the archived public access Terrain Resource Information Management (TRIM), stereo aerial photography DEM and airborne light detection and ranging (LiDAR). These three DEMs showed similar findings in terms of alpine basin attributes, however, significant differences were also found in the context of application uses and other finer scales.

The article offers information on the correlations between hydrological processes at the hillslope scale and observations of the reaction of watersheds following rainfall. It examines the efficiency of a parsimonious model of catchments processes, as well as field observations on the Panola Mountain Research Watershed (PMRW) Georgia, in the United States. It is observed that the relationship between recession analysis discharge and hydrological processes is consistent with a linear reservoir for the hillslope. It is revealed that a model with parallel reservoirs efficiently provides examination for both hillslope reaction to rainfall and non-linear recession behavior.

Most mountain catchments worldwide are exploited for hydropower production causing significant alterations of their natural regime. Hydrological and water resources modelling in these catchments is challenging because the alterations of natural streamflow caused by hydropower production are often significant, while capturing their variability in space and time requires critical data concerning the hydraulic infrastructures and their operational schedules. These data are difficult to acquire, thereby hindering the possibility to correctly simulate the complex interaction between the natural hydrological cycle and water uses. To overcome these limitations we propose a framework that relies solely on publicly available data which provides accurate simulation of both streamflow and hydropower production. The proposed framework is illustrated by means of the HYPERstreamHS hydrological model applied to the Adige catchment, a large watershed of the south-eastern Alpine region whose streamflow is strongly impacted by 39 large hydropower systems, 22 of which connected to storage reservoirs, with an overall mean annual production that accounts for about 14% of the total Italian hydropower production. We analyzed the impact on modelled hydropower production of commonly adopted simplifications in the production schedule as well as of the hydropower systems, which are often characterized by a complex infrastructure with several interlinked derivations and conveyance intakes. Our simulations highlight how an accurate topological representation of hydraulic infrastructures is crucial to correctly represent water transfers, more important than capturing the operational schedules when reservoir oscillations are a small fraction of the total head. On the contrary, scheduling is important for systems in which reservoir oscillations account for a significant portion of the total head. Furthermore, we show that simplifications motivated by difficulties in data collection combine in a non-linear manner with an overall impact difficult to assess. We propose this framework for accurate modelling of hydropower production at regional and national scales, particularly in studies dealing with the projection of climate change and competing uses on water resources and renewable energy. [ABSTRACT FROM AUTHOR]

• An extended monthly Budyko model was developed by incorporating TWS from GRACE. • The performance of the extended Budyko model was improved compared to the original Budyko model. • The contributors of intra-annual streamflow variability are mainly P (50%), TWSC (11%) and their combined action (-21%). • The regulation of intra-annual TWS on streamflow was analyzed. Streamflow from forested mountain watersheds is critical to aquatic ecosystems and social development in watersheds. However, understanding the intra-annual variability of streamflow is limited by the lack of observation of terrestrial water storage (TWS) in large-scale watersheds. This study developed a monthly Budyko framework incorporating TWS from the Gravity Recovery and Climate Experiment (GRACE). The extended Budyko framework was applied using four classic Budyko equations in the Qinba Mountains. The results showed that the extended Budyko framework could competently represent the relationship between monthly water supply and demand, with better performance than the original Budyko framework. Based on the extended Budyko framework, this study further quantified the contributors of streamflow variability using the variance decomposition method. The dominant contributor to intra-annual streamflow variability was precipitation (50%), followed by TWS (11%) and their covariance (-21%) in this region. Specifically, precipitation played a dominant role on streamflow variability in summer and autumn, while evapotranspiration and TWS significantly impacted streamflow in spring and winter, respectively. Furthermore, the hydrologic effects of rainfall intensity and vegetation were investigated to explain streamflow variability. As the rainfall intensity decreases, more precipitation is partitioned into evapotranspiration and TWS, while the increase of rainfall intensity leads to the partitioning of precipitation into streamflow. Similarly, monthly vegetation promotes the partitioning of precipitation into TWS, while inhibiting the partitioning of precipitation into streamflow. The opposite effect of vegetation on streamflow and TWS is weakened due to the neglect of TWS at an annual timescale, which may lead to an overestimation of the effect of annual vegetation on streamflow. The results have implications for improving the performance of the Budyko framework to reveal the relationship between monthly water supply and demand and understanding streamflow variability at an intra-annual timescale. [ABSTRACT FROM AUTHOR]

• SWR was examined in soils derived from different sediments in an alpine watershed. • SWR is controlled by SOC for aeolian sediments and by PSD for fluvial sediments. • SOC enhances plant-available water capacity for sandy soils but not for silty soils. • The mattic surface soil horizon has a high functionality in storing water and SOC. Soil's hydrological and ecological functions depend largely on soil water retention, which is affected by both structural and compositional soil properties. Studies have shown that alpine soils derived from sediments with different origins in the northeast Qinghai-Tibetan Plateau differ significantly in terms of particle size distribution, bulk density and soil organic carbon content. However, the variation pattern and its drivers of soil water retention in this region remain unclear. In this study, soil water retention characteristics (saturated soil water capacity, field capacity, wilting point and plant available water capacity) from different geomorphic settings (i.e., hillslopes, alluvial fans and floodplains) of an alpine catchment in the western part of the Qilian Mountains were analyzed in relation to sediment types and soil properties. Results show that soil water retention varies significantly with sediment types. Soils with an aeolian origin have a higher capacity to retain water compared with soils developed on fluvial sediments. Variations in soil water retention are mainly controlled by particle size distribution for fluvial sediments and by soil organic carbon content for aeolian sediments. The accumulation of soil organic carbon enhances plant available water capacity for sandy fluvial sediments but not for silty fluvial and aeolian sediments. The critical eco-hydrological functions of the mattic surface soil horizon in relation to water retention, runoff regulation and erosion control were highlighted for the alpine ecosystems. By deciphering sedimentological and pedological controls of soil water retention, this study improves the understanding of the evolution and functioning of alpine soils, which has further implications for other sedimentary ecosystems. [ABSTRACT FROM AUTHOR]

The watershed-scale distribution and loss of potentially toxic elements (PTEs) through soil erosion from slope lands to a watershed has not yet been systematically studied, especially in small mountain watersheds with high geological background PTEs in Southwest China. In this study, the spatial distribution, loss intensities and ecological risks of 12 PTEs were investigated in 101 soil samples from four types of land use in a typical watershed, Guizhou Province. Moreover, in order to avoid over- or underestimation of the contamination level in such specific geologies with significant variability in natural PTE distribution, the local background values (local BVs) were calculated by statistical methods. The dry arable land had the highest loss intensity of PTEs and was the largest contributor of PTEs (more than 80%) in the watershed, even though it covers a much smaller area compared to the forest land. The loss of Cd, As, Sb, and Hg from slope arable lands into the watershed leads to a relatively high potential ecological risk. The study suggested that both PTEs content with different types of land-uses and intensities of soil loss are of great importance for PTEs' risk assessment in the small watershed within a high geological background region. Furthermore, in order to reduce the loss of PTEs in soil, the management of agricultural activities in arable land, especially the slope arable land, is necessary. [ABSTRACT FROM AUTHOR]

The Soil and Water Assessment Tool (SWAT) has been applied successfully in temperate environments but little is known about its performance in the snow-dominated, forested, mountainous watersheds that provide much of the water supply in western North America. To address this knowledge gap, we configured SWAT to simulate the streamflow of Tenderfoot Creek (TCSWAT). Located in central Montana, TCSWAT represents a high-elevation watershed with ∼85% coniferous forest cover where more than 70% of the annual precipitation falls as snow, and runoff comes primarily from spring snowmelt. Model calibration using four years of measured daily streamflow, temperature, and precipitation data resulted in a relative error (RE) of 2% for annual water yield estimates, and mean paired deviations (Dv) of 36 and 31% and Nash-Sutcliffe (NS) efficiencies of 0.90 and 0.86 for monthly and daily streamflow, respectively. Model validation was conducted using an additional four years of data and the performance was similar to the calibration period, with RE of 4% for annual water yields, Dv of 43% and 32%, and NS efficiencies of 0.90 and 0.76 for monthly and daily streamflow, respectively. An objective, regression-based model invalidation procedure also indicated that the model was validated for the overall simulation period. Seasonally, SWAT performed well during the spring and early summer snowmelt runoff period, but was a poor predictor of late summer and winter base flow. The calibrated model was most sensitive to snowmelt parameters, followed in decreasing order of influence by the surface runoff lag, ground water, soil, and SCS Curve Number parameter sets. Model sensitivity to the surface runoff lag parameter reflected the influence of frozen soils on runoff processes. Results indicated that SWAT can provide reasonable predictions of annual, monthly, and daily streamflow from forested montane watersheds, but further model refinements could improve representation of snowmelt runoff processes and performance during the base flow period in this environment. [ABSTRACT FROM AUTHOR]

Soil sampling is an integral component of fertility evaluation and nutrient recommendation for efficient use of nutrients in crop production. Little attention has been devoted to evaluating methodology for sampling watersheds under dryland agriculture. A stratified random sampling methodology for sampling the Appayapally watershed in Mahabubnagar district of Andhra Pradesh state in the semi-arid tropical region of India was adopted and evaluated. The watershed has an area of about 500 ha, with gentle sloping lands (<1% slope), and 217 farmers own land in the watershed. The soils are Alfisols. A total of 114 soil samples were collected from the top 15-cm layer to represent the entire watershed. Each sample was a composite of 7-8 cores, randomly collected from the area represented by a crop and group of farmers. The soil samples were air dried, ground, and analyzed for pH, electrical conductivity (EC), organic carbon (C), total nitrogen (N), and extractable phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), sodium (Na), sulfur (S), zinc (Zn), manganese (Mn), iron (Fe), copper (Cu), and boron (B). Statistical analysis of the results on soil fertility parameters showed that the mean- or median-based results of soil tests performed in the study did not differ significantly when the sample set size varied from 5 to 114 (100% of the population). Our results indicate that farmers' fields in the Appayapally watershed are uniform in the chemical fertility parameters studied, and even a small sample set size can represent the whole population. However, such a sampling strategy may be applicable only to watersheds that are very gently sloping and where fertilizer use is very low, resulting in an overall low fertility in the whole watershed. [ABSTRACT FROM AUTHOR]

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The article presents a study which investigates the application of the precipitation runoff evapotranspiration hydrological response unit model (PREVAH) to the glacierized Alpine Upper Salzach basin in Austria. The model aims to guide water management strategies, and low flow forecasting studies. By comparing simulated outlet discharge, likewise the soil moisture reserve and phreatic surface level through observations, model results were validated. An explanation of important terms which were used in the study including glacier melt, and glacier balance is presented. Details on the method by which the model was applied, and the simulation results are also discussed.

The article focuses on the application of the Alpine 3D model to the Goldbergkees basin in Austria for glacier mass balance, and glacier runoff studies. Alpine 3D is a distributed model for land surface-atmosphere interaction. The objective of the study is to enable a detailed evaluation of the model that provides model performance statistics and make the model originally designed for snow science. The strengths and weaknesses of the model, likewise its applicability to glaciological problems, and glacier hydrology are also explored.

The article focuses on the snowmelt runoff in a waterless mountain watershed in Tarim Basin, China. It explores the degree-day factor (DDF) of snowmelt runoff model (SRM) which varies on the basis of shortwave solar radiation and snow reflective power. It presents the model efficiency and efficiency values of snowmelt runoff for calibration year and two validation years, respectively. It indicates that the sensitivity of the model to lapse rate and snow albedo parameterization are important for the success of the simulation and the work out of watershed.

The article presents a study which focuses on the assessment of future runoff from highly glacierized alpine drainage basins. The galcierized alpine catchments are assessed by the use of glacio-hydrological model for the period 2007-2100. It discusses that scenarios for the seasonal change in temperature and precipitation derived from climate models. It is also inferred that glacier surface mass balance and runoff are calculated in daily time steps using a temperature index melt and accumulation models. Information regarding the calibration and validation of the model using a distributed temperature index melt and accumulation model is also discussed.

In large mountainous catchments, shallow unconfined alluvial aquifers play an important role in conveying subsurface runoff to the foreland. Their relatively small extent poses a serious problem for ground water flow models on the river basin scale. River basin scale models describing the entire water cycle are necessary in integrated water resources management and to study the impact of global climate change on ground water resources. Integrated regional-scale models must use a coarse, fixed discretization to keep computational demands low and to facilitate model coupling. This can lead to discrepancies between model discretization and the geometrical properties of natural systems. Here, an approach to overcome this discrepancy is discussed using the example of the German-Austrian Upper Danube catchment, where a coarse ground water flow model was developed using MODFLOW. The method developed uses a modified concept from a hydrological catchment drainage analysis in order to adapt the aquifer geometry such that it respects the numerical requirements of the chosen discretization, that is, the width and the thickness of cells as well as gradients and connectivity of the catchment. In order to show the efficiency of the developed method, it was tested and compared to a finely discretized ground water model of the Ammer subcatchment. The results of the analysis prove the applicability of the new approach and contribute to the idea of using physically based ground water models in large catchments. [ABSTRACT FROM AUTHOR]

Lakes are dynamic processors of nutrients and may hold an active role in modifying the water chemistry of stream systems. In this study, we examine the influence of lakes and an important terrestrial component-forest cover-on the nutrient levels of stream water in 11 Rocky Mountain (Idaho) watersheds. Water samples were collected from the inflow and outflow of lakes with varying amounts of upstream lakes and forested area during spring runoff-and summer base flow. During base flow, mean total nitrogen concentrations at the inflow of final lakes were significantly related to relative upstream lake area, increasing from 34 to 103 μg N L-1 as upstream lake cover in the watersheds increased from 0% to 4%. Forest cover was not significantly correlated with total nitrogen concentrations exported from the watersheds. However, similar to other studies, inflow nitrate concentrations were negatively correlated with relative forest cover. At the scale of individual lakes, dissolved organic carbon and dissolved organic nitrogen increased, and nitrate was significantly reduced from inflows to outflows. The results indicate a potentially critical role of mountain lakes in governing nitrogen flux downstream, and suggest the role of lakes as nitrogen sinks or sources may reverse between spring runoff and summer base flow. [ABSTRACT FROM AUTHOR]

Alluvial fans are continuously being developed for residential, industrial, commercial, and agricultural uses in southern California. Development and alteration of alluvial fans need to consider the possibility of mud and debris flows from upstream mountain watersheds affected by fires. Accurate prediction of sediment yield (or hyper-concentrated sediment yield) is essential for the design, operation, and maintenance of debris basins to safeguard properly the general populace. This paper presents a model for the prediction of sediment yields that result from a combination of fire and subsequent storm events. The watersheds used in this analysis are located in the foothills of the San Gabriel Mountains in southern California. A multiple regression analysis is first utilized to establish a fundamental statistical relationship for sediment yield as a function of relief ratio, drainage area, maximum 1-h rainfall intensity and fire factor using 45 years of data (1938-1983). In addition, a method for multi-sequence sediment yield prediction under fire conditions was developed and calibrated using 17 years of sediment yield, fire, and precipitation data for the period 1984-2000. After calibration, this model was verified by applying it to provide a prediction of the sediment yields for the 2001-2002 fire events in southern California. The findings indicate a strong correlation between the estimated and measured sediment yields. The proposed method for sequence sediment yield prediction following fire events can be a useful tool to schedule cleanout operations for debris basins and to develop an emergency response strategy for the southern California region where plentiful sediment supplies exist and frequent fires occur. [ABSTRACT FROM AUTHOR]

The article presents an analysis of the factors that control rates and extent of soil erosion processes in a representative catchment of the Northern Ethiopian Highlands. It examines the evolution of geomorphic process rates at different time periods and develops a sediment budget for the catchment. According to the study, deforestation and the introduction of permanent agriculture brought environmental changes in the area, thereby, increasing the intensity of most of the erosion processes. Moreover, it was found that rockfall from cliffs and rock fragment transport on debris slopes under rangeland are important geomorphic processes in the study location.

Abstract: When a field or a small watershed is repeatedly surveyed for soil water content, locations can often be identified where soil water contents are either consistently larger or consistently less than the study area average. This phenomenon has been called temporal stability, time stability, temporal persistence, or rank stability in spatial patterns of soil water contents. Temporal stability is of considerable interest in terms of facilitating upscaling of observed soil water contents to obtain average values across the observation area, improving soil water monitoring strategies, and correcting the monitoring results for missing data. The objective of this work was to contribute to the existing knowledge base on temporal stability in soil water patterns using frequent multi-depth measurements with Multisensor Capacitance Probes (MCPs) installed in a coarse-texture soil under multi-year corn production. Water contents at 10, 30, 50, and 80 cm depths were measured every 10 min for 20 months of continuous observation from May 2001 to December 2002. The MCPs revealed temporal stability in soil water content patterns. Temporal stability was found to increase with depth. The statistical hypothesis could not be rejected (P <0.0001) that data collected each 10 min, each 2 h, each day, and each week had the same temporal stability. The locations that were best for estimating the average water contents were different for different depths. The best three locations for the whole observation period were the same as the best locations for a month of observations in about 60% of the cases. Temporal stability for a specific location and depth could serve as a good predictor of the utility of this location for estimating the area-average soil water content for that depth. Temporal stability could be efficiently used to correct area-average water contents for missing data. Soil water contents can be upscaled and efficiently monitored using the temporal stability of soil water content patterns. [Copyright &y& Elsevier]

Alpine regions are particularly affected by seasonal variations in water demand and water availability. Especially the winter period is critical from an operational point of view, as being characterised by high water demands due to tourism and low water availability due to the temporal storage of precipitation as snow and ice. The clear definition of summer and winter periods is thus an essential prerequisite for water resource management in alpine regions. This paper presents a GIS-based multi criteria method to determine the winter season. A snow cover duration dataset serves as basis for this analysis. Different water demand stakeholders, the alpine hydrology and the present day water supply infrastructure are taken into account. Technical snow-making and (winter) tourism were identified as the two major seasonal water demand stakeholders in the study area, which is the Kitzbueheler region in the Austrian Alps. Based upon different geographical datasets winter was defined as the period from December to March, and summer as the period from April to November. By determining potential regional water balance deficits or surpluses in the present day situation and in future, important management decisions such as water storage and allocation can be made and transposed to the local level. [ABSTRACT FROM AUTHOR]

Coalbed methane (CBM) development raises serious environmental concerns. In response, concerted efforts have been made to collect chemistry, salinity, and sodicity data on CBM produced water. However, little information on changes of stream water quality resulting from directly and/or indirectly received CBM produced water is available in the literature. The objective of this study was to examine changes instream water quality, particularly sodicity and salinity, due to CBM development in the Powder River watershed, which is located in the Rocky Mountain Region and traverses the states of Wyoming and Montana. To this end, a retrospective analysis of water quality trends and patterns was conducted using data collected from as early as 1946 up to and including 2002 at four U.S. Geological Survey gauging stations along the Powder River. Trend analysis was conducted using linear regression and Seasonal Kendall tests, whereas, Tukey's test for multiple comparisons was used to detect changes in the spatial pattern. The results indicated that the CBM development adversely affected the water quality in the Powder River. First, the development elevated the stream sodicity, as indicated by a significant increase trend of the sodium adsorption ratio. Second, the development tended to shrink the water quality differences among the three downstream stations but to widen the differences between these stations and the farthest upstream station. In contrast, the development had only a minor influence on stream salinity, as indicated by that the stream electrical conductivity exhibited either no trend or a marginally significant positive trend. Hence, the CBM development is likely an important factor that can be managed to lower the stream sodicity. The management may need to take into account that the effects of the CBM development were different from one location to another along the Powder River. [ABSTRACT FROM AUTHOR]

This study used measured diurnal surface-water cycles to estimate daily evapotranspiration (ET) and seepage for a seasonally flooded sinkhole wetland. Diurnal surface-water cycles were classified into five categories based on the relationship between the surface-water body and the surrounding ground-water system (i.e., recharge/discharge). Only one class of diurnal cycles was found to be suitable for application of this method. This subset of diurnal cycles was used to estimate ET and seepage and the relative importance of each transfer process to the overall water budget. The method has limited utility for wetlands with erratic hydrologic regimes (e.g., wetlands in urban environments). This is due to violation of the critical assumption that the inflow/outflow rate remains constant throughout the day. For application to surface-water systems, the method is typically applied with an assumed specific yield of 1.0. This assumption was found to be invalid for application to surface-water systems with a noncylindrical pond geometry. An overestimation of ET by as much as 60% was found to occur under conditions of low pond stage and high water loss. The results demonstrate the high ET rates that can occur in isolated wetlands due to contrasting roughness and moisture conditions (oasis and clothesline effects). Estimated ET rates ranged from 4.1 to 18.7 mm/day during the growing season. Despite these large ET rates, seepage (recharge) was found to be the dominant water loss mechanism for the wetland. [ABSTRACT FROM AUTHOR]

The article discusses the use of radionuclide techniques to determine the floodplain sedimentation rates in an alpine watershed. It explores the vertical profiles of the activities which are measured on floodplain sediment cores and upland soil cores along the Soda Buttle Creek and the Yellowstone River to determine the floodplain sedimentation rates. It also discusses the position of mine tailings from a 1950 impoundment failure which is used as a stratigraphic marker to estimate the sedimentation rates and to make comparisons with rates provided by radionuclide-based methods.

Knowledge on processes of charcoal transportation is crucial for fire reconstruction based on sedimentary charcoal. Charcoal is susceptible to long-distance transport by water. A lake basin with a large and long catchment area is likely to accumulate charcoal from many fires, not only those produced by fires nearby the lakeshore. Here we test the potential of charcoal transportation by analysing sedimentary charcoal accumulated in an underground lake within a karstic massif. Fires cannot spread around the lake, nor within the karstic massif. Organic materials, including charred particles, are generated several kilometres from the lake on the karstic plateau above. The pattern of sedimentary charcoal shows that the underground lake records continuously produced charcoal by wild fires or human-made biomass burning (slash-and-burn, charcoal kilns) over centuries and millennia, but also stored charcoal from eroded soils. Although the charcoal series shows a certain high variability signal, fire frequency reconstruction cannot be performed owing to chronological uncertainties. The charcoal accumulation corresponds to a more or less regular background input. Such background input is empirically well described in palaeo-fire reconstruction, but was never experimentally displayed. This study provides evidence that the pattern (surface, length, slope, etc.) of catchment areas is crucial for interpreting sedimentary charcoal series. Large catchment areas draining long rivers are not suitable for high-resolution and spatially precise fire reconstructions. [ABSTRACT FROM AUTHOR]

The modelling of complex, dynamic and uncertain socioenvironmental systems requires close collaboration between research disciplines and stakeholders at all levels, for if such models are representations of aspects of reality, how can it be possible to build them without inputs from people who interact with the systems in reality? This paper reflects on findings of case study research involving stakeholders in knowledge creation through conceptual and formal model building to support upland water catchment management. The uncertainty, multiple scales and conflicting understandings of stakeholders inherent in natural resource management necessitate a strong focus on participatory processes in integrated modelling. This leads to the recognition that problems and solutions should be identified by the stakeholders themselves, emphasising the intersection and complementarity of lay and expert knowledge. Stakeholders in this context comprise varied groups such as land managers (e.g. grouse moor managers and sheep farmers), water companies and water users, tourists, residents, policy-makers and researchers. Models are used at multiple stages to help formulate problems, create and compare conceptual understanding, and explore implications. This requires the involvement of stakeholders early in the problem formulation and research process to help answer the 'right' questions and provide 'relevant' outputs. This poses a number of interesting new challenges for the organisation of research. In contrast to traditional approaches of matching model components to expertise in the research team, modelling expertise must adapt to answer the questions and priorities that emerge from stakeholder engagement. [ABSTRACT FROM AUTHOR]

This article describes the development of a calibrated hydrologic model for the Blue River watershed (867 km2) in Summit County, Colorado. This watershed provides drinking water to over a third of Colorado's population. However, more research on model calibration and development for small mountain watersheds is needed. This work required integration of subsurface and surface hydrology using GIS data, and included aspects unique to mountain watersheds such as snow hydrology, high ground-water gradients, and large differences in climate between the headwaters and outlet. Given the importance of this particular watershed as a major urban drinking-water source, the rapid development occurring in small mountain watersheds, and the importance of Rocky Mountain water in the arid and semiarid West, it is useful to describe calibrated watershed modeling efforts in this watershed. The model used was Soil and Water Assessment Tool (SWAT). An accurate model of the hydrologic cycle required incorporation of mountain hydrology-specific processes. Snowmelt and snow formation parameters, as well as several ground-water parameters, were the most important calibration factors. Comparison of simulated and observed streamflow hydrographs at two U.S. Geological Survey gaging stations resulted in good fits to average monthly values (0.71 Nash-Sutcliffe coefficient). With this capability, future assessments of point-source and nonpoint-source pollutant transport are possible. [ABSTRACT FROM AUTHOR]

Many government agencies and other organizations sample natural alpine and subalpine surface waters using varying protocols for sample storage and filtration. Simplification of protocols would be beneficial if it could be shown that sample quality is unaffected. In this study, samples collected from low ionic strength waters in alpine and subalpine lake inlets and outlets in the western United States were used to evaluate (1) effects of refrigerated storage time on the chemistry of unfiltered samples, and (2) differences in sample filtration protocols. No analytes exhibited significant changes when stored less than 48 h. Six analytes (pH, sodium, ammonium, potassium, chloride, sulfate) exhibited statistically significant (but small) changes when storage time exceeded 48 h. Two analytes (calcium, nitrate) were significantly higher when samples were field filtered than when filtered in the laboratory, but the differences were also small. For waters similar to those in this test, unfiltered refrigerated samples may be stored up to 48 h without compromising sample quality. The small differences between field and lab filtration do not justify the expense, training, and contamination risk of field filtration. [ABSTRACT FROM AUTHOR]

Instream processing may substantially alter nutrient export from forested watersheds. This study tested how instream uptake of N and P were affected by successional differences in the accumulation of large wood and debris dams in a 66-year chronosequence formed by five watersheds within the Hubbard Brook Experimental Forest (HBEF), NH. Nutrient enrichment releases in summer 1998 were used to measure the uptake velocities of phosphate, nitrate and ammonium for five streams within HBEF, and results indicated that uptake of PO43- was closely associated with forest age. In 2004, we quantified volume and abundance of large wood in each stream to test whether large wood abundance could be linked to nitrate uptake as well as phosphate. The volume of instream wood increased with forest age, at an apparent rate of 0.03 m³ (100 m)-1 per year for these early to mid-successional forests (r² = 0.95); however, debris dam frequency did not. Instead, debris dam frequency, when controlled for stream size, followed a U-shaped distribution, with high dam frequency in very young forests, low frequency in forests around 20-30 years of age and increasing dam frequency again as forests matured. Phosphate uptake velocity increased strongly with both forest age and large wood volume (r² = 0.99; p < 0.001 in both cases); however, nitrate and ammonium uptake were not related to either factor. We attribute the positive relationship between phosphate uptake velocity and forest age/large wood volume to increased abiotic adsorption of phosphate by the inorganic sediments retained by wood. Nitrogen uptake in these streams is primarily biologically driven and did not vary predictably with these structural features of channels. We expect wood abundance to increase in HBEF streams as the forest matures, with a subsequent increase in stream phosphate uptake capacity. [ABSTRACT FROM AUTHOR]

We compared seven small (2-6 km2) upland watersheds located in two land-use categories (logged and unlogged) in the Adirondack Park (New York). Watersheds were considered logged if the lands were managed for timber harvesting, while unlogged watersheds have not been logged for at least 85 years. Riparian litter species composition and biomass were estimated for each stream. In-stream leaves were also sampled to assess invertebrate community assemblages and leaf species composition. Leaf material in logged catchments was composed mainly of litter that decomposes more quickly and is thus of higher quality to the invertebrate consumer (i.e., Acer spp., Populus tremuloides and Fraxinus americana). Leaves in unlogged catchments contained a higher abundance of invertebrates and detritivorous insects throughout the year. The results suggest that alterations to the invertebrate community related to land-use may result in differing energy processing rates in logged Adirondack watersheds. [ABSTRACT FROM AUTHOR]

Summary: A distributed energy-balance model was developed for simulating snowpack evolution and melt in rugged terrain. The model, which was applied to a 43-km2 watershed in the Tobacco Root Mountains, Montana, USA, used measured ambient data from nearby weather stations to drive energy-balance calculations and to constrain the model of Liston and Sturm [Liston, G.E., Sturm, M., 1998. A snow-transport model for complex terrain. Journal of Glaciology 44 (148), 498–516] for calculating the initial snowpack thickness. Simulated initial snow-water equivalent ranged between 1cm and 385cm w.e. (water equivalent) with high values concentrated on east-facing slopes below tall summits. An interpreted satellite image of the snowcover distribution on May 6, 1998, closely matched the simulated distribution with the greatest discrepancy occurring in the floor of the main trunk valley. Model simulations indicated that snowmelt commenced early in the melt season, but rapid meltout of snow cover did not occur until after the average energy balance of the entire watershed became positive about 45 days into the melt season. Meltout was fastest in the lower part of the watershed where warmer temperatures and tree cover enhanced the energy income of the underlying snow. An interpreted satellite image of the snowcover distribution on July 9, 1998 compared favorably with the simulated distribution, and melt curves for modeled canopy-covered cells mimicked the trends measured at nearby snow pillow stations. By the end of the simulation period (August 3), 28% of the watershed remained snow covered, most of which was concentrated in the highest parts of the watershed where initially thick accumulations had been shaded by surrounding summits. The results of this study provide further demonstration of the critical role that topography plays in the timing and magnitude of snowmelt from high mountain watersheds. [Copyright &y& Elsevier]

In mountain watersheds, the increased demand for clean water resources has led to an increased need for an understanding of ground water flow in alpine settings. In Prospect Gulch, located in southwestern Colorado, understanding the ground water flow system is an important first step in addressing metal loads from acid-mine drainage and acid-rock drainage in an area with historical mining. Ground water flow modeling with sensitivity analyses are presented as a general tool to guide future field data collection, which is applicable to any ground water study, including mountain watersheds. For a series of conceptual models, the observation and sensitivity capabilities of MODFLOW-2000 are used to determine composite scaled sensitivities, dimensionless scaled sensitivities, and 1% scaled sensitivity maps of hydraulic head. These sensitivities determine the most important input parameter(s) along with the location of observation data that are most useful for future model calibration. The results are generally independent of the conceptual model and indicate recharge in a high-elevation recharge zone as the most important parameter, followed by the hydraulic conductivities in all layers and recharge in the next lower-elevation zone. The most important observation data in determining these parameters are hydraulic heads at high elevations, with a depth of less than 100 m being adequate. Evaluation of a possible geologic structure with a different hydraulic conductivity than the surrounding bedrock indicates that ground water discharge to individual stream reaches has the potential to identify some of these structures. Results of these sensitivity analyses can be used to prioritize data collection in an effort to reduce time and money spend by collecting the most relevant model calibration data. [ABSTRACT FROM AUTHOR]

Abstract: The morphology of step-pools and cascades reflect the geological and climatic factors affecting channels in mountain watersheds. This study uses longitudinal and cross-section surveys to describe a headwater stream in the Boston Mountains of the Ozarks Plateau region in Arkansas and develop morphological relationships for comparisons with other regions. In the Bowers Hollow Creek watershed (3.5 km2), located within the boundaries of the Upper Buffalo Wilderness Area, step height and wavelength relationships are generally similar to those reported from other regions. Step-pool reaches were widely distributed in a discontinuous manner throughout the watershed. Average values of the sampled reaches are: reach slopes, 0.105 m/m; width, 6.10 m; crest particle sizes, 440 mm; step heights, 0.87 m; and step wavelengths, 6.62 m. The mean step steepness for the watershed was 0.13, whereas the mean length of a reach step to height ratio was 9:1. A comparison of morphological definitions found that the values of step height and steepness can vary by >30% according to how step parameters are defined. Step height is particularly sensitive; thus, comparison of step height-based relationships from published data requires great care. [Copyright &y& Elsevier]

Keywords: Mountain lakes; Global change; Nutrients; Temperature EN Mountain lakes Global change Nutrients Temperature 1 2 2 06/10/20 20200701 NES 200701 Lakes within mountain landscapes integrate and reflect both their landscape position and environmental stressors. This barrage of change is altering mountain watersheds and aquatic ecosystems in many ways; the papers in this topical collection describe variety of environmental changes in mountain environments and subsequent influences on their lake ecosystems. Mesocosm experiments conducted by Preston et al. ([15]) explored the effects of rising temperature on alpine lake zooplankton response. [Extracted from the article]

Norman E. "Jake" Peters had a long and distinguished career with the US Geological Survey (USGS), from 1980 until he retired in 2010 in order to, as he put it, "get some papers out and save the project money." Jake and company then applied age-dating tracer techniques to evaluate the relative contributions of hillslope and riparian water to streamflow (Burns et al., [1]; Peters et al., [5]; Van Meerveld et al., 2015). From his USGS/Panola base, Jake took his science on the road. [Extracted from the article]

The Bhagirathi River, a proglacial melt water stream of the Gangotri Glacier, is the principal source of the Ganges river system. The upper part of the basin lies in the high altitude region of the Garhwal Himalayas and is extensively covered by glaciers. We provide hydro-meteorological insight into a severe storm that produced unusual high rains in June 2000 in the uppermost part of the Bhagirathi River. This storm was concentrated upstream of Gangotri town and triggered landslides/rockslides at several locations between the glacier snout and Gangotri town. One of the major rockslides blocked the Bhagirathi River at Bhujbas, about 3 km downstream of the Gangotri Glacier snout, creating an artificial lake at this location. High stream flow in the river, generated by rapid runoff response from mountain slopes along with melt runoff from the glacier, quickly increased the level of water stored in the artificial lake. Daily rainfall in this region rarely exceeds 10 mm, while total rainfall during this 6-day storm was 131.5 mm. This unusual rain event occurred during the tourist season in June, consequently trapping a large number of tourists and vendors in this area. Sudden release of stored water generated floods that created havoc downstream of the artificially created lake. This paper presents the hydrological and meteorological information related to such an unusual and devastating event observed in the high altitude region of the Himalayas. [ABSTRACT FROM AUTHOR]

Hydrological budgets and flow pathways have been quantified for a small upland catchment (1.76 km²) in the northeast of Scotland. Water balance calculations for four subcatchments identified spatial variability within the catchment, with an estimated runoff enhancement of up to 25% for the upper western area, compared with the rest of the catchment. Data from spatial hydrochemical sampling, over a range of flow conditions, were used to identify the principal hillslope runoff mechanisms within the catchment. A hydrochemical mixing analysis revealed that runoff emerging from springs in various locations of the hillslope accounted for a significant proportion of flow in the streams, even during storm events. A hydrological model of the catchment was calibrated using the calculated stream flows for four locations, together with results from the mixing analysis for different time points. The calibrated model was used to predict the temporal variability in contributions to stream flow from the hillslope springs and soil water flows. The overall split ranged from 57% : 43% spring water: soil water in the upper eastern subcatchment, to 76% 24% in the upper western subcatchment. [ABSTRACT FROM AUTHOR]

The spatial representativeness of gauging stations was investigated in two low-mountainous river basins near the city of Trier, southwest Germany. Longitudinal profiles during low and high flow conditions were sampled in order to identify sources of solutes and to characterize the alteration of flood wave properties during its travel downstream. Numerous hydrographs and chemographs of natural flood events were analysed in detail. Additionally, artificial flood events were investigated to study in-channel transport processes. During dry weather conditions the gauging station was only representative for a short river segment upstream, owing to discharge and solute concentrations of sources contiguous to the measurement site. During artificial flood events the kinematic wave velocity was considerably faster than the movement of water body and solutes, refuting the idea of a simple mixing process of individual runoff components. Depending on hydrological boundary conditions, the wave at a specific gauge could be entirely composed of old in-channel water, which notably reduces the spatial representativeness of a sampling site. Natural flood events were characterized by a superimposition of local overland flow, riparian water and the kinematic wave process comprising the downstream conveyance of solutes. Summer floods in particular were marked by a chronological occurrence of distinct individual runoff components originating only from a few contributing areas adjacent to the stream and gauge. Thus, the representativeness of a gauge for processes in the whole basin depends on the distance of the nearest significant source to the station. The consequence of our study is that the assumptions of mixing models are not satisfied in river basins larger than 3 km². [ABSTRACT FROM AUTHOR]

River discharges vary strongly through time and space, and quantifying this variability is fundamental to understanding and modelling river processes. The river basin is increasingly being used as the unit for natural resource planning and management; to facilitate this, basin-scale models of material supply and transport are being developed. For many basin-scale planning activities, detailed rainfall-runoff modelling is neither necessary nor tractable, and models that capture spatial patterns of material supply and transport averaged over decades are sufficient. Nevertheless, the data to describe the spatial variability of river discharge across large basins for use in such models are often limited, and hence models to predict river discharge at the basin scale are required. We describe models for predicting mean annual flow and a non-dimensional measure of daily flow variability for every river reach within a drainage network. The models use sparse river gauging data, modelled grid surfaces of mean annual rainfall and mean annual potential evapotranspiration, and a network accumulation algorithm. We demonstrate the parameterization and application of the models using data for the Murrumbidgee basin, in southeast Australia, and describe the use of these predictions in modelling sediment transport through the river network. The regionalizations described contain less uncertainty, and are more sensitive to observed spatial variations in runoff, than regionalizations based on catchment area and rainfall alone. [ABSTRACT FROM AUTHOR]

This study presents a new method of detecting individual treetops from lidar data and applies marker-controlled watershed segmentation into isolating individual trees in savanna woodland. The treetops were detected by searching local maxima in a canopy maxima model (CMM) with variable window sizes. Different from previous methods, the variable windows sizes were determined by the lower-limit of the prediction intervals of the regression curve between crown size and tree height. The canopy maxima model was created to reduce the commission errors of treetop detection. Treetops were also detected based on the fact that they are typically located around the center of crowns. The tree delineation accuracy was evaluated by a five-fold, cross-validation method. Results showed that the absolute accuracy of tree isolation was 64.1 percent, which was much higher than the accuracy of the method, which only searched local maxima within window sizes determined by the regression curve (37.0 percent). [ABSTRACT FROM AUTHOR]

Agricultural watersheds in the upper Midwest are the major source of nutrients to the Mississippi River and Gulf of Mexico, but temporal patterns in nutrient export and the role of hydrology in controlling export remain unclear. Here we report on NO3--N, dissolved reactive phosphorus (DRP), and total P export from three watersheds in Illinois during the past 8–12 years. Our program of intensive, long-term monitoring allowed us to assess how nutrient export was distributed across the range of discharge that occurred at each site and to examine mechanistic differences between NO3--N and DRP export from the watersheds. Last, we used simple simulations to evaluate how nutrient load reductions might affect NO3--N and P export to the Mississippi River from the Illinois watersheds. Artificial drainage through under-field tiles was the primary mechanism for NO3--N export from the watersheds. Tile drainage and overland flow contributed to DRP export, whereas export of particulate P was almost exclusively from overland flow. The analyses revealed that nearly all nutrient export occurred when discharge was ≥ median discharge, and extreme discharges (≥ 90th percentile) were responsible for >50% of the NO3--N export and >80% of the P export. Additionally, the export occurred annually during a period beginning in mid-January and continuing through June. These patterns characterized all sites, which spanned a 4-fold range in watershed area. The simulations showed that reducing in-stream nutrient loads by as much as 50% during periods of low discharge would not affect annual nutrient export from the watersheds. [ABSTRACT FROM AUTHOR]

The area of the Western Route Project for South-to-North Water Transfer (WRP) in China, located in the upper reaches of the Yangtze River and the marginal area of the Qinghai-Tibet Plateau, has sufficient water resources that transfers could be considered. However, potential transfers are limited due to a fragile eco-environment. The eco-environmental water demand is the key constraint for determining the available quantity of water that could be transferred in view of the existing water demand for local social and economic development. Considering the effect on the eco-environment, this study investigates the available quantity of transferable water in the WRP for the dual purpose of protecting the local eco-environment and decreasing the crisis of water resources in the western areas by considering the water demand for river channel eco-environment downstream of the dams as the main constraint. In order to estimate the eco-environmental water demand, the low runoff and Tennant methods are studied. According to the results of risk analysis, the proposed schemes for water transfer have high reliability and low risk The risk will be further reduced !f in the future reservoirs are operated jointly. [ABSTRACT FROM AUTHOR]

The article examines the headwater ecosystem delivered by certain types of land use in the U.S. The researchers focused on nitrogen enrichment in a Rocky Mountain watershed undergoing rapid expansion of population and residential development. There study sites were located along the headwaters of the Blue River to Lake Dillon, a major source of drinking water for Denver, Colorado. It is stated that the biotic capacity of headwater ecosystems to assimilate increase in inorganic nitrogen from residential development may be insufficient to prevent nitrogen enrichment over multiple aquatic ecosystems downstream.

Abstract: This paper summarizes a project that analyzed previous research undertaken in the upper San Pedro basin of Arizona (USA) and Sonora (México). Various groups had undertaken the previous research over the past decade. A literature review and an e-mail survey resulted in a list of 10 lessons for watershed planning research as well as suggested watershed planning strategies. [Copyright &y& Elsevier]

An ecohydrological-erosion model for semi-arid mountain catchment has been developed and integrated with rainfall-runoff model for estimating upland delivery rates of sediments resulted from individual storm at the outlet of Wadi Surdud catchment (2370 km2), Tihama, Yemen. The degradation of soil resources in the mountainous areas of Yemen is evident due to long-term and intensive human impacts on those vulnerable ecological environments of the indigenous terraces. If current trends continue, Yemen may permanently lose a significant portion of its productive land to soil erosion due to lack of preservation of indigenous soil and water conservation systems. This area has been degraded into nearly desert-like condition. Yet, geological and even historic data indicate that the natural ecological environments should be much better than it appears. To restore the ecological environment, we need to know its potentials. The erosion and sedimentation processes of the upland watersheds have to be assessed by means which do not rely on historical storm flow data. Methods that depend on available or measurable representative data were developed for a deterministic approach of the erosion process. This study takes advantage of physically based methods and Geographic Information Systems (GIS) and uses the Digital Elevation Model (DEM) and observed meteorological and hydrological data to model the runoff and sediment yield in an attempt to assess the potential natural ecological environments. Our results show that the effective Curve Number (CN) and soil detachability are the factors that determine the potential natural ecological environments. In this paper the study of runoff and sediment delivery is based on one stream gauging station and 10 rainfall gauging stations. Discharge was calculated for the period from July, 15, 1998 to October, 10, 1998 which resulted from 10 rainfall storms. A comparison of observed and predicted sediment yield shows a good agreement with a coefficient of determination of 0.85. [ABSTRACT FROM AUTHOR]

On 12 August 1997, the lower part of Diadem Glacier in the southern Coast Mountains of British Columbia fell into Queen Bess Lake and produced a train of large waves. The waves overtopped the broad end moraine at the east end of the lake and ?ooded the valley of the west fork of Nostetuko River. The displacement waves also incised the out?ow channel across the moraine. Stratigraphic and sedimentologic evidence supports the conclusion that the ?ood had two phases, one related to wave overtopping and a second to breach formation. Empirical equations were used to calculate the peak discharge of the ?ood at various points along the west fork of the Nostetuko valley and to describe the attenuation of the ?ood wave. The velocity of the ?ood was also calculated to determine the time it took for the ?ood to reach the main fork of Nostetuko River. The highest peak discharges were achieved in the upper reach of the valley during the displacement phase of the ?ood. Peak discharge declined rapidly just below the moraine dam, with little change thereafter for approximately 7 km. Empirical formulae and boulder measurements indicate a rise in peak discharge in the lower part of the west fork valley. We suggest that ?ow in the upper part of the valley records the passage of two separate ?ood peaks and that the rise in discharge in the lower part of the valley is due to amalgamation of the wave and breach peaks. Hydraulic ponding in con?ned reaches of the valley extended the duration of the ?ood. In addition, erosion of vegetation and sediment in the channel and valley sides may also have exerted an in?uence on the duration and nature of ?ooding. Sediments were deposited both upstream and downstream of channel constrictions and on a large fan extending out into the trunk Nostetuko River valley. This study extends our understanding of the variety and complexity of outburst ?oods from naturally dammed lakes. It also shows that simple empirical and other models for estimating peak discharges of outburst ?oods are likely to yield erroneous results. Copyright 2005 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Although the large variations in nitrate export from forested watersheds have been attributed to a variety of natural and disturbance-related factors, baseflow nitrate concentrations in 49 mid-Appalachian forested watersheds were most strongly related to differences in bedrock geology. Within the mid-Appalachian region of Pennsylvania, Maryland and West Virginia, watersheds dominated by Pottsville and Allegheny sandstone (PVA), Catskill, Chemung, and Pocono shale and sandstone (CCP), and Mauch Chunk shale and Greenbrier limestone (MCG), respectively, exhibited significantly different low, intermediate, and high mean stream nitrate concentrations. Soil pH, soil percent N concentration (%N), soil C:N mass ratio, soil exchangeable Ca, watershed slope, and the occurrence of white ash (Fraxinus americanaL.), sugar maple (Acer saccharumMarsh.), and eastern hemlock (Tsuga canadensisL.) were related significantly to bedrock geology type as well as stream nitrate levels. Other factors such as past land disturbances (fire and agriculture) and stand age (old-growth) typically were associated with only one bedrock geology type. However, within a bedrock geology type, past agriculture and the presence of old-growth forest may be important in explaining stream nitrate concentrations on an individual watershed basis. The basal area of black locust (Robinia pseudoacaciaL.), a species that enhances soil nitrogen levelsvianitrogen fixation, showed a moderate positive correlation with stream nitrate concentrations. Bedrock geology explained the most variation in winter (49%) and summer (32%) stream nitrate concentrations. Bedrock geology may have been a better predictor of stream nitrate concentrations than soil chemistry, because the geologic variation was better assessed at the regional scale of this study compared to soil chemistry, which varies at the micro-scale due to topographic, vegetation, microbial, and climatic influences. Results of this study suggest that bedrock geology is an important factor to consider when assessing forest nitrogen dynamics at a broad landscape scale. [ABSTRACT FROM AUTHOR]

Describes the aquatic biology of Atna watercourse and evaluates the usefulness of the various parameters for environmental monitoring program. Importance of natural variation in ecosystem parameters; Parameters utilized to determine the ecological status of the ecosystem; Diversity of variation in both terrestrial and aquatic ecosystem components of Atna watershed.