3rd Order Streams Research Articles

Watershed prioritization of Kailali district through morphometric parameters and landuse/landcover datasets using GIS

Watershed prioritization is considered an important tool for soil and watershed management. This study focuses on the watershed prioritization of the Kailali district in terms of soil erosion, considering morphometric parameters and land use/landcover (LULC) datasets using GIS. ALOS DEM of 30 m resolution was used to delineate sub-watersheds and calculate linear, areal, and relief morphometric parameters. Similarly, Esri LULC 2021 (Sentinel-2 imagery at 10 m resolution) was used to calculate LULC parameters. An integrated approach of Principal Component Analysis (PCA) and Weighted Sum Analysis (WSA) was used for prioritization. PCA was used to reduce selected parameters, calculate the correlation matrix, and define the significant parameters. WSA was used to define weightage value, and Compound Value (CV) was calculated for the ranking of sub-watersheds. 22 sub-watersheds with at least 3rd order stream and 15 parameters were selected for prioritization. PCA integrated with WSA was found to be effective for prioritization. The findings showed that about 61.58% of the watershed area is in the high-priority category, suggesting those areas are at a higher risk of erosion. Therefore, different land rehabilitation programs and bioengineering techniques should be focused on the sub-watershed of high-priority categories followed by medium and low-priority categories to control further soil erosion. The adopted methodology of prioritization can also be performed for multi-hazard mapping.

Flow alterations in rivers due to unconventional oil and gas development in the Ohio River basin

Unconventional oil and gas (UOG) exploration and development in the Ohio River basin has been a controversial issue for the past decade. The process of extracting gas and oil from shale formations utilizes significant amounts of water with little to no recycling in the region. The environmental risks to date have largely focused on air and water quality, with some attention paid to noise pollution. This study examines the risk for excessive water withdrawals and potential for negative impacts of low streamflow, which have largely not been addressed, as basin-wide studies have indicated that UOG will not significantly alter flow at large scales. The smallest watersheds, however, are often not monitored and therefore no historical record of flow is present. Using modelled estimates of historic flow, the impacts of UOG-related water withdrawals in HUC12 watersheds (approximately 1st to 3rd order streams) across the eastern Ohio River basin were estimated. Modelling of the effect of well operations showed that >10 % and >20 % reductions in streamflow occurred at least episodically in 53 % and 42 % of the HUC12 watersheds analyzed, respectively, amounting to 8.8 % and 2.4 % of active days. Although such severe reductions were usually infrequent in a particular stream, they could have lasting negative impacts on the stream biota. These flow reductions have the potential to affect downstream users, including regionally-endangered species. The legal framework surrounding water withdrawal permitting should have a substantial impact on flow reduction, but a lack of sufficient monitoring and clear reporting of water withdrawal sources hinders effective monitoring and protection of stream and riparian habitats.

Morphometric Analysis by Using Remote Sensing & QGIS Approach to Evaluate the Aquifer Response of Two Sub Watersheds of Coastal Kerala

Global increase in demand of water resources stepped up due to climate change and increase in population, stimulates an efficient development, management and conservation of water resources by quantifying the available water within the catchment to bridge the gap between its demand and availability. Initiated at a watershed scale, it is important to quantitatively evaluate the geomorphological parameters, since all the hydrologic and geomorphic processes may be accounted and balanced within a watershed. This study presents an excellent morphometric characterization of Payppara and Tikovil sub watersheds of Meenachil basin, in the state of Kerala, India, evaluated using SRTM DEM at 30m×30m spatial resolution as input to QGIS. The important linear morphometric aspects like stream order, length of stream segments, bifurcation ratio, Rho coefficient, the areal morphometric aspects like form factor, drainage density, stream frequency, elongation ratio, length of overland flow and relief aspects like ruggedness number, watershed relief were calculated for a comprehensive understanding of the geomorphic characteristics of the watershed. The general terrain of Tikovil was found to be steep but it was relatively mild for Payppara. The gravity flow paths traced by few 4th order, 3rd order and 2nd order stream segments of Payppara were identified as potential groundwater recharge zones. The derived morphometric characteristics benefits a better understanding of the formation of erosive and permeable surface flow paths in response to precipitation, the principal input to the hydrological budget.

Unravelling the spatiotemporal variation of pCO2 in low order streams: Linkages to land use and stream order

Headwater streams make the majority of cumulative stream length in a river basin, carbon dioxide (CO2) emission from headwater (low order) streams is thus an essential component. Anthropogenic activities in headwater areas such as land use change and land use practices can strongly modify terrestrial carbon and nutrient input, which could affect the level of partial pressure of dissolved carbon dioxide (pCO2) and CO2 degassing from streams. However, there are large uncertainties in estimates due to the lack of data in subtropical rivers of rapidly developing rural regions. The spatiotemporal variation and driving factors of the pCO2 and CO2 degassing from low-order streams remain to be explored. In this study, we assess multi-spatial scale effects of land use on pCO2 dynamics in seven headwater tributary rivers in Central China during 2016, 2017 and 2018 in rainy and dry seasons. Our results reveal that the stream pCO2 level consistently increases as the stream order increases from 1 to 3 under apparent seasonal variations. Riverine pCO2 is positively related to the percentage of urban land and cropland surrounding the river segments, but is negatively related to the percentage of forest land. The stream pCO2 is more closely correlated with the 1000 and 2000 m diameters of circular buffers at upstream sampling sites than the circular buffers with 100 and 500 m diameters. There exist significant relationships of pCO2 with the concentrations of TN, TP, DO, and DOC in the low-order streams. The partial redundancy analysis quantifies the relative importance of anthropogenic land uses, natural factors and water chemical variables in mediating stream pCO2, showing that influences of anthropogenic land uses (urban and cropland) on pCO2 decrease, with a percentage role of 34%, 14%, and 4% in the 1st-, 2nd- and 3rd-order streams, respectively. The impact of nutrients on pCO2, however, increases as the stream order increases. Urban influence on stream pCO2 also decreases as stream order increases. Our study highlights the effect of land use/land cover types and stream order on riverine pCO2 and provides new insight into estimating CO2 emission in headwater streams. Future studies are needed on the linkage between riverine CO2 degassing and stream orders under changing land use conditions.

Plant species richness in riparian forests: Comparison to other forest ecosystems, longitudinal patterns, role of rare species and topographic factors

This study aimed to analyze plant species richness in riparian forests at both local and regional scales across several watersheds in the Sudetes (Poland, Central Europe). Specifically, species richness in riparian forest was compared to other forest types in the same region. It was also hypothesized that due to high complexity and dynamics, riparian forests share a higher number of rare species. In addition, the longitudinal pattern of species richness was analyzed at both local and regional scales. Finally, the effect of topography on species richness in riparian forests in spring areas and along rivers of various sizes was analyzed.Riparian forests have significantly higher alpha diversity than beech and ravine forests, but oak forests showed a similar level of diversity. However, a comparison of accumulation curves showed, that riparian forests are the most species-rich at a regional scale. All forest types had a similar share of rare species. Eight uniform groups of rare species were distinguished in riparian forests and reflected the riparian complexity and dynamics.The number of plant species per plot was highest in spring areas and decreased from headwaters to lower reaches. The estimated total number of species showed a similar pattern; however, the highest number was estimated for riverine forests along 3rd order streams and therefore suggest a unimodal pattern of gamma diversity along a longitudinal (upstream–downstream) gradient. The effect of topographic variables on species richness differed depending on the position in the river network.

Geomorphic Analysis, Morphometric-based Prioritization and Tectonic Implications in Chite Lui River, Northeast India

Abstract River morphometry is a useful approach in basin analysis which helps to interprets fluvially originated landforms. The aim of the present work is to evaluate the morphometric and morphotectonic parameters along with prioritization for soil erosion and water availability in Chite Lui watershed. Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) is a useful approach to find out soil erosion and ground water potential zone with an aim to achieve successful management of a watershed. It helps to examine the susceptibility zone in watershed. The present paper documents the delineation of 14 sub-watersheds in Chite Lui River at 3rd order stream. Its prioritization has been performed using several morphometric parameters namely drainage density, elongation ratio and many other parameters using Analytical Hierarchical Process (AHP). Sub-watersheds are ranked from 1-14 based on soil erosion and groundwater potential zones. The Chite Lui watershed is a fifth order drainage basin with a total area of 52.7 km2. The tectonic parameters of the watershed as the asymmetry value is 34%, indicates the structural control over the area either by uplift or tilting. The hypsometric integral value is 0.5 and the valley width height ratio is 0.05 which also suggest tectonic activity in the area. Sinuosity related many parameters along with geomorphic indices like stream power index (SPI), stream gradient index (SL) and topographic wetness index (TWI) were also calculated to suggest the watershed health. The present paper shows that the morphometric analysis is highly relevant and efficient in delineating susceptibility zones.

Spatial Groundwater Modelling of Micro Watersheds – A case study at Junewani watershed, Hingna Taluk, Nagpur, Maharashtra

A model is a simplified representation of the complex natural world. The groundwater model provides a quantitative framework for synthesizing field information and for conceptualizing hydrogeological purposes. The present study aims to utilize remotely sensed data, Geographical Information System (GIS), and limited flow modeling to identify the groundwater recharge management practices carried out in the Junewani watershed of the Nagpur district. In this study, Modflow-NWT, in conjunction with spatial analyses, is used for modeling Groundwater flow in Junewani Watershed located at 78.90°E and 21.03°N in Nagpur District, Maharashtra. Since minimal data on flow parameters are available and aquifer systems are also heterogeneous, water level data observed from dug wells has also been used to generate the groundwater flow directions. The study area consists of 1st, 2nd and 3rd order streams and is covered with Black cotton soil and Vesicular Basalt underneath. Watershed boundary conditions, elevation details, drainage patterns, layer properties, permeability values, average rainfall, etc. are given as input for the model. The initial input data has been procured from GSDA Nagpur and through field observations. This study discusses the micro watershed groundwater modeling carried out mainly in a spatial environment supported by results of limited flow modelling, but the results and insights from this study will help in better understanding the GW flow regime after the recharge decisions were taken and the recharge practices were operated. It has been observed that recharge practices in surface dams and desilting have been beneficial at some places, while groundwater has decreased at other places. Thus it helps in decision making regarding the development of GW recharge and utilization.

Spatial and temporal variation of the diet of the flag tetra Hyphessobrycon heterorhabdus (Characiformes: Characidae) in streams of the Eastern Amazon

ABSTRACT Spatial and temporal variations in streams promote large fluctuations of resource availability, thus affecting the diet of fishes. We evaluated the effects of hydrological periods and stream order within periods on the diet of the flag tetra Hyphessobrycon heterorhabdus. We analyzed 160 stomachs in eight streams ranging from 1st to 3rd order between dry and flood period. Sampled streams belonged to a well-preserved area in the Eastern Amazon. The flag tetra is omnivorous, with a tendency towards insectivory. During the dry period, the species exhibited a higher amount of autochthonous than allochthonous items. Fish consumed more allochthonous items in 1st and 2nd order streams in the dry period and in 1st and 3rd order streams in the flood period. These results reflect the interactions between temporal and longitudinal factors on resource availability and its influence on fish diet. This pattern is probably dependent on the extensive riparian vegetation as a direct and indirect source of food for stream fish.

Developing quantifiable approaches for delineating suitable options for irrigating fallow areas during dry season-a case study from Eastern India.

Harvesting surface runoff during monsoon season for further utilization in crop production during the post-monsoon season is now becoming an effective solution to mitigate water scarcity problems. In this study, multi-criteria analysis-analytic hierarchy process (MCA-AHP)-based approach was envisaged for rainwater harvesting (RWH) zoning for a case study area, i.e., two districts of Odisha state situated in Eastern India. In spite of having a large irrigation network in the study area, major portion of these two densely populated and agriculture dominated districts remains fallow during dry seasons. Suitable locations for RWH structures such as farm pond, check dam, and percolation tanks were identified through Boolean conditions. RWH potential map was generated using different thematic layers namely land use/land cover (LU/LC), geomorphology, slope, stream density, soil type, and surface runoff. AHP-based MCA technique was used to integrate these thematic layers by assigning weights to the thematic layers and ranks to the individual theme features on 1-9 AHP Saaty's scale, considering their relative importance on RWH potential of the study area. The Natural Resources Conservation Service-Curve Number method was used to derive surface runoff using Climate Hazards Group Infra-Red Precipitation with Station rainfall data, satellite-derived LU/LC and FAO soil maps. In comparison to single cropped areas in 48% of the total study area, only 4% area was under double and triple cropped areas during 2016-2017. Moderate runoff was observed in > 50% of the study area dominated by agricultural landscape. Nearly 40%, 25.11%, and 32.45% of the study area indicated very high, high, and moderate RWH potentials, respectively. Particularly, very high RWH potential is observed in the eastern and central portion of the study area. The use of appropriate RWH structures in less irrigated areas will facilitate multiple cropping and will substitute the use of sub-surface water harvesting practices. In these two districts, 73 check dams and 153 percolation tanks are prescribed along the 2nd- and 3rd-order streams. In coarser textured soil, nearly 306km2 and 608km2 areas are identified as moderate and highly suitable zones for percolation tank construction on ground, while in fine soil, around 786km2 area is identified as suitable for farm pond construction. Majority of the suitable zones for percolation tanks is found in Jajpur district, while suitability for adoption of farm pond and check dam is more in Bhadrak district. It is expected that implementation of the prescribed RWH structures can mitigate the threats of flood, drought, soil erosion, and enhance the soil moisture and cropping intensity significantly. The use of GIS platform with the spatial layers and the methodology adopted can be updated and replicated in larger regions in a shorter time. The spatially explicit maps are offering insights to different themes, providing useful information to the water resource managers, and may improve the decision-making process.

Qurain AL-Thamad Valley Hydrological Aspects Extraction Using Remote Sensing and GIS Techniques

In the arid to semi-arid lands the extracted hydrological features are essential ones, since their effect on water projects managing, agricultural projects administrating, and animals grazing, so that this research is considered to be vital research because the climate of Qurain AL-Thamad basin is arid climate and basin region inhabited by many tribes who works in agricultural and grazing fields. The illustration of hydrological features using morphometric analyses is optimum since the quantization issue of basin factors, in the past this would be difficult using classical procedures (i.e. using paper topographic maps and planmeter). Recently as in this work modern procedures has been used (i.e. satellite imagery DEM as ancillary image and Arc GIS 10.5 as geo-measuring and spatio-analyzing program).
 The pattern of Qurain AL-Thamad basin's drainage network shows dendritic configuration in low orders streams and parallel configuration in the high order streams. The spatial analysis using GIS environment categorize basin's shape parameters into three categories: firstly one is the linear parameters with streams divided into 1st order streams with (611.587 km) length, 2nd order streams with (384.015 km) length, 3rd order streams with (181.868 km) length, and 4th order streams with (103.674 km) length. Bifurcation ratios were calculated, Rb1 is (2.046), Rb2 is (1.869), and Rb3 is (1.624), with (1.852) Rb mean value. Secondly categorize deals with areal parameters; The longitudinal drainage density was (0.259 km??), the drainage frequency was (0.035 stream /km²), Drainage Texture value was (0.338 stream / km ), the elongation ratio was (0.483), the circularity ratio value was (0.244), the form factor was (0.183) , and the relief ratio was (0.447). according to these quantitative results the flood hazard in the basin main stream is absent, basin soil is high permeable and region rainfall rate is very low, there is significant differences in region geological structures solidity, land steepness and relief ratio are low valued yielding a few water erosion power, sediment yield, and runoff flood peak in the basin water catchment area.

Predilection of sustainable recharge structures using morphometric parameters and decision making model in the Vaniyar sub basin, South India

The morphometric parameters are depicting the hydrological reaction through geographic information systems (GIS) and geospatial techniques used for water conservation. In this area, drainage system shows a dendritic pattern occasion where the most outrageous number of streams found in the primary request and the stream arrange extended by receding in stream number. The preference criteria were chosen in the pappiredipatti watershed compared to other watersheds in the sub basin based on slope condition, rainfall, and weathered zone thickness. The highest mean bifurcation ratio is 4.9 at yercaud watershed whereas the lowest mean bifurcation ration is 1.8 in kadattur watersheds. The mean bifurcation proportion was 3.125 which demonstrate that the discharge design is influenced by auxiliary aggravations. The Elongation ratio lowest in 0.53 at kadattur and highest at KRW is 0.8, form factor esteems were 0.67 and 0.1.92 which specify stretched state of the bowl having a compliment high point of the stream for longer spans. Flowing streams of the prolonged basin are less demanding to oversee for accommodating to deciding the impact of the catchment territory on hydrological valuation. In the pappiredipatti watershed was chosen preference criteria of recharge structures, number of structures 8, 12, and 30 of check dams were built on 1st, 2nd, 3rd order stream individually. Two permeation lakes were developed nearer to 3rd order stream. Artificial recharge structures in 1st order are lower than in 2nd order, according to the morphometric investigation, the 2nd and 3rd order stream are described by high penetrable, high infiltration limit and low help, which is conducive for the recharge. The accompanying observations made while settling on the sort and plan of maintainability structures for the proper location.

Frequency ratio modelling using geospatial data to predict Kimberlite Clan of rock emplacement zones in Dharwar Craton, India

Kimberlite clan of rocks (KCR) comprising of mantle derived ultrabasic rocks such as Kimberlite and related Lamproites and Lamprophyres,are the primary source of diamond. Locating the KCR is first step in the diamond exploration, which is highly challenging in the field due to (i) very small spatial extent of KCR pipes (ii) high susceptibility of KCR to weathering and alteration on exposure to atmosphere, owing to their ultrabasic composition. Predictive statistical models using the geospatial data are often used to minimize the search and the present work attempts to apply the Frequency Ratio (FR) based predictive model in GIS to prepare KCR potential zone maps based on the relationship between the already explored KCR locations and the factors that favour their emplacement. Wajrakarur Kimberlite Field (WKF) in the Dharawar Craton of India, with more than 30 explored kimberlite pipes is selected as the study area. Geospatial technology has been used to generate thematic maps such as known KCR pipe locations, lineament density, lineament buffer zone, lineament intersection buffer zone, drainage anomaly buffer zone, geomorphology, and classified image showing distribution of mineral such as clay, iron oxide and calcrete, which are surface expression of KCR emplacement from various sources. Landsat 8 OLI satellite data, ASTER DEM were used in preparing the geomorphology, lineament map, and band ratio based mineral classified map. The thematic maps were converted to raster grid of 10 sq. m. FR values for each unit in each thematic map were obtained by correlating the spatial relationship between thematic map and the 25 locations of the 33 “known” KCR locations in WKF used for FR modelling. Cumulative FR value were obtained by carrying out overlay analysis of the thematic maps, which are classified into five classes by Natural Breaking method as (i)Very Low Favourable (VLF), (ii) Low Favourable (LF), (iii)Moderate favourable (MF), (iv)High Favourable (HF), and (v)Very High Favourable (VHF). The model was validated by ground verification at random sites and statistical method. During the ground visit, we observed KCR-like lithology’s at four new sites that have calcrete exposure at limited spatial extent and also some pieces of ultrabasic rocks similar to the explored sites. To ascertain their chemical composition of the samples were plotted in the MgO-K2O-Al2O3 ternary diagram. All the four samples fall in the Kimberlite/Lamproite field confirming them to be KCR. The FR predictive model was also validated statistically. Total 13 locations, including 8 site out of 33 known KCR locations, one newly discovered pipe by GSI and the four locations discovered during this study were used for the validation. Statistical validation shows that 84% of model accuracy is achieved. The study reveals that Lineament Intersection, and circular drainage anomaly in 3rd order streams, lineament density are significant themes in predicting KCR emplacement zones. The study demonstrates the utility of statistical based model such as FR model in predicting the location of KCR emplacement, even with statistically insignificant distribution of KCRs and can be applied elsewhere in the world to locate the KCRs. In the process, we report discovery of four new KCR pipes in the WKF.

Using maximum entropy modeling to predict suitable habitat locations for the Cutshin Crayfish (Cambarus taylori)

The Cutshin Crayfish (Cambarus taylori) is a recently described species which is endemic to the Middle Fork of the Kentucky River basin. The Middle Fork of the Kentucky River lies within the anthracite coal fields of Eastern Kentucky, and thus a conservation assessment of C. taylori is warranted. The goal of this study was to predict suitable habitat locations for C. taylori through use of maximum entropy modeling (MaxEnt). The Middle Fork of the Kentucky River’s crayfish fauna was surveyed during the summer of 2014. The occurrence data from this study coupled with landscape scale environmental variables—such as stream order and land use data—was used to create the model. The mean area under the receiver operating characteristic curve (AUC) value was 0.898, showing the model had high predictive accuracy. The model indicated high probability of occurrence in streams at the southern end of the basin, and a low probability of occurrence at the northern end of the basin. Stream order and stream sinuosity had the highest contribution to the model showing that C. taylori prefers 3rd and 4th order streams with low sinuosity. Although the AUC value showed high predictive accuracy for the model, predicted sites will need to be ground validated to confirm the model’s predictive accuracy.

Habitat requirements of two common aquatic snakes, Regina septemvittata and Nerodia sipedon sipedon

Regina septemvittata (Queen Snakes)and Nerodia sipedon sipedon (Common Watersnake) are semi-aquatic colubrid snakes that utilize streams for their primary source of prey. Both species are currently listed by the International Union for Conservation of Nature as stable. The goal of this study was to determine which specific habitat aspects affect the presence or absence of R. septemvittata and N. sipedon sipedon. Snakes were collected in the summer and fall of 2017 from August to October in North Fork of Short Creek, a 3rd order stream located just south of West Liberty, WV. Using the Ohio QHEI form to quantify stream quality and program PRESENCE to generate Logistic Regression Models, stream sub-habitat types were compared with occurrence data. Resulting models revealed which specific sub-habitat types were associated with positive occurrence. Univariate models selected for riparian zone determined by the width and predominant cover present with an AIC weight of 0.499. Multivariate models selected riparian zone with an AIC of 0.372 and riparian plus total stream health with AIC of 0.185. Our preliminary data indicates that snake presence is related to both riparian zone and water quality. This suggests that sufficient cover quality and stream health are required to maintain populations of Regina septemvittata and Nerodia sipedon sipedon.

Background values of gold, potentially toxic elements and emerging high-tech critical elements in surface water collected in a remote northern European environment

A geochemical surfacewater survey, focused on 2nd and 3rd order streams, was carried out in the Oppdal/Berkåk area in Norway. Stream water was collected at 168 sample sites, covering a 1500-km 2 survey area. Electrical conductivity, pH, alkalinity and temperature were recorded in the field. Electrical conductivity and pH were also determined once more in the laboratory. The cations Br, Cl, F, NO 2 , NO 3 , PO 4 and SO 4 were determined by ion-chromatography (IC) on unacidified, laboratory filtered samples. Inductively coupled plasma quadrupole mass spectrometry (ICP-QMS) was used to analyse field filtered and acidified samples for 63 elements. In addition, inductively coupled plasma atomic emission spectrometry (ICP-AES) was used to determine 27 elements. One aim of the survey was to test whether today's ICP-QMS analyses are sensitive enough to directly use surface water efficiently for gold prospecting. The two known gold occurrences in the area are marked by low level Au anomalies in stream water (0.006 µg/l). These values are just above the detection limit of 0.001 µg/l and it must be concluded that today's detection limits are still not low enough to use stream water for routine Au (and In) prospecting. The anions as determined by IC were most problematic in terms of number of samples below detection limit. Increased anthropogenic activities in the lowlands are marked by slightly enhanced NO 3 values in the streams. An As, Mo, Sb, V anomaly marks the main skiing area near Oppdal but is probably geogenic. In general surface water geochemistry of, for example, Ca, Ce, Cu, K, La, Rb, SO 4 and Sr reflects the geology of the area well. Methodological tests indicate that it should be sufficient to take unfiltered samples in the field and to filter and acidify these in the evening at home base. The dataset provides a good overview of background concentrations and variation of almost 70 chemical elements in stream water from a remote northern European survey area. Supplementary material: Table S1 showing the analytical program, isotopes measured and detection limits, Table S2 with analytical results of the international reference materials used for quality control and Fig. S1 with geochemical maps for all elements are available at: https://doi.org/10.6084/m9.figshare.c.4012885

Trophic dynamics of macroinvertebrate communities of a subtropical river in China

This study was the first attempt to resolve both spatial and temporal patterns of macroinvertebrate trophic dynamics in a Chinese subtropical river continuum, the Shengli River, from 1st to 4th order. Gut content analysis was adopted to assess the trophic basis and consumption rates of communities. Furthermore, annual energy flow food webs were constructed. Trophic basis analyses showed that 34–79% of the diet of macrozoobenthos in the Shengli River and its tributaries was amorphous detritus. Leaf litter was the second most important food source, followed by animal material. Filamentous algae, diatoms, and fungi served only as subsidies, contributing no more than 5% to total consumption. The macroinvertebrates in 1st and 3rd order streams appeared to show seasonal consumption patterns of different food types, while the communities in 2nd and 4th order streams had the same diet composition throughout the year. Total consumption rates of the communities increased from 1st to 3rd order streams, and declined in 4th order streams. The energy flow food web of 1st order streams was simpler than those of higher‐order streams. With increasing stream order, the food webs increased in complexity until 3rd order, and became simpler again in 4th order streams.

Effects of cypress knee roughness on flow resistance and discharge estimates of the Turkey Creek watershed

Abstract Effects of cypress knee roughness on flow resistance and discharge estimates of the Turkey Creek watershed. In this study effects of cypress knees as vegetation resistance factor on Turkey Creek watershed discharge calculation were analyzed. The Turkey Creek watershed is a 3rd order stream system draining an approximate area of 5,240 ha. It is located at 33°08' N latitude and 79°47' W longitude, approximately 60 km north-west of City of Charleston in South Carolina (USA). Turkey Creek (WS 78) is typical of other watersheds in the south Atlantic coastal plain. In the case of Turkey Creek watershed, one of the main channels and riparian floodplain vegetation contains cypress trees. Cypress trees live in moist or swampy regions along the Atlantic coastal plain. The cypress trees are characterized by the unique root system called knees that appear just above the water line, up to 1.2 m above water surface. This study is conducted to examine the effects of roughness of cypress knee as related to its shape (diameter and height) on discharge estimates of the Turkey Creek watershed. Hydraulic characteristics of the cypress knees were determined by field inventory in selected cross-section along the main stream channel. The Pasche method was used to calculate the total Darcy–Weisbach friction factor in discharge capacity calculation of the study watershed. The results of this study show that the effect of vegetation shape in the Pasche approach is significant. If the variability of vegetation stem diameter is taken into consideration in the calculations, an increase by 10–32% in the values of friction coefficients occurs.

Landscape context and the biophysical response of rivers to dam removal in the United States.

Dams have been a fundamental part of the U.S. national agenda over the past two hundred years. Recently, however, dam removal has emerged as a strategy for addressing aging, obsolete infrastructure and more than 1,100 dams have been removed since the 1970s. However, only 130 of these removals had any ecological or geomorphic assessments, and fewer than half of those included before- and after-removal (BAR) studies. In addition, this growing, but limited collection of dam-removal studies is limited to distinct landscape settings. We conducted a meta-analysis to compare the landscape context of existing and removed dams and assessed the biophysical responses to dam removal for 63 BAR studies. The highest concentration of removed dams was in the Northeast and Upper Midwest, and most have been removed from 3rd and 4th order streams, in low-elevation (< 500 m) and low-slope (< 5%) watersheds that have small to moderate upstream watershed areas (10–1000 km2) with a low risk of habitat degradation. Many of the BAR-studied removals also have these characteristics, suggesting that our understanding of responses to dam removals is based on a limited range of landscape settings, which limits predictive capacity in other environmental settings. Biophysical responses to dam removal varied by landscape cluster, indicating that landscape features are likely to affect biophysical responses to dam removal. However, biophysical data were not equally distributed across variables or clusters, making it difficult to determine which landscape features have the strongest effect on dam-removal response. To address the inconsistencies across dam-removal studies, we provide suggestions for prioritizing and standardizing data collection associated with dam removal activities.

Estimate the geomorphological parameters of the Arang watershed in Chhattisgarh region

This study was conducted for the Arang watershed of the Chhattisgarh, India. Several geomorphological parameters of the watershed were determined using standard procedure. The Arang is 3 rd order watershed and comprises of 10 villages. Predominant soil of the watershed is clay loam. The watershed receives an average annual rainfall of 1400 mm, out of which the monsoon season (June to October) contributes more than 85 per cent rainfall. The number of 1 st , 2 nd and 3 rd Order were found to be 20, 4, 1, respectively. The different geomorphometric parameters of watershed were determined and result showed that total length of stream segments were 26.14, 9.37, 8.56 km, respectively. Area of sub-basin for 1st, 2nd and 3rd order streams and of different order streams were to be 32.35, 43.94, and 54.50 km 2 , respectively, for 1 st , 2 nd and 3 rd order streams. The mean bifurcation ratio for the watershed was found to be 4.64. The length ratio, circularity ratio and elongation ratio for the Arang watershed were determined and found to be 2.724, 0.9148 and 0.973, respectively. The hypsometric integral of the watershed was calculated to be 0.998 km. The drainage density, length of over land flow and constant of channel maintenance of the watershed were found to be 0.808 km/km 2 , 0.618 km and 1.237 km, respectively. The main channel slope of the watershed was 0.005 whereas compactness co-efficient of the watershed was 1.093. The stream frequency, basin shape factor, form factor, and ruggedness number of the watershed were 0.458 km 2 , 2.578, 0.387, 0701 and 0.016, respectively. The values of relative relief and relative ratio of the watershed was found to be 1.452×10 -3 and 1.687×10 -3 , respectively. The weighted average slope of the entire watershed was found to be 1.5 per cent. This parameter which indicates that topography of watershed is flat.

Densities and Population Sizes of Clinch DaceChrosomussp. cf.sayloriin the Upper Clinch River Basin in Virginia

Estimates of abundance and density for the imperiled Clinch Dace (Chrosomus sp. cf. saylori) are needed across its range to indicate where populations exist and estimate their long-term viability. We generated estimates of population extent, measured in km of potentially occupied habitat, based on 206 site visits from four fish surveys since 1999 within the Clinch Dace's putative range. Next, we used mark–recapture surveys to estimate Clinch Dace densities in five occupied streams. A linear regression model generated from these data was used to transform single-pass count data into estimated abundance with 90% prediction intervals (PI) for Clinch Dace in sampled reaches. We combined estimates of individual population sizes to estimate global abundance. Finally, we examined the correlation between habitat variables and Clinch Dace abundance in occupied streams. Clinch Dace populations at low densities potentially occupy 31.5 km of the approximately 351 km of 2nd- and 3rd-order streams in northern Russell a...