scholarly journals The Cumulative Effects of Forest Disturbance and Climate Variability on Streamflow in the Deadman River Watershed

Forests ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 196 ◽  
Author(s):  
Krysta Giles-Hansen ◽  
Qiang Li ◽  
Xiaohua Wei
Keyword(s):  
Climate Variability ◽  
Forest Cover ◽  
Forest Disturbance ◽  
Climatic Variability ◽  
High Flow ◽  
The Body ◽  
Cumulative Effects ◽  
Low Flow ◽  
Mean Flow ◽  
River Watershed

Climatic variability and cumulative forest cover change are the two dominant factors affecting hydrological variability in forested watersheds. Separating the relative effects of each factor on streamflow is gaining increasing attention. This study adds to the body of literature by quantifying the relative contributions of those two drivers to the changes in annual mean flow, low flow, and high flow in a large forested snow dominated watershed, the Deadman River watershed (878 km2) in the Southern Interior of British Columbia, Canada. Over the study period of 1962 to 2012, the cumulative effects of forest disturbance significantly affected the annual mean streamflow. The effects became statistically significant in 1989 at the cumulative forest disturbance level of 12.4% of the watershed area. The modified double mass curve and sensitivity-based methods consistently revealed that forest disturbance and climate variability both increased annual mean streamflow during the disturbance period (1989–2012), with an average increment of 14 mm and 6 mm, respectively. The paired-year approach was used to further investigate the relative contributions to low and high flows. Our analysis showed that low and high flow increased significantly by 19% and 58%, respectively over the disturbance period (p < 0.05). We conclude that forest disturbance and climate variability have significantly increased annual mean flow, low flow and high flow over the last 50 years in a cumulative and additive manner in the Deadman River watershed.

scholarly journals The effects of cumulative forest disturbance on streamflow in a large watershed in the central interior of British Columbia, Canada

2012 ◽  
Vol 16 (7) ◽  
pp. 2021-2034 ◽  
Author(s):  
M. Zhang ◽  
X. Wei
Keyword(s):  
British Columbia ◽  
Large Scale ◽  
Forest Disturbance ◽  
Climatic Variability ◽  
Natural Disturbance ◽  
Low Flow ◽  
Mean Flow ◽  
Salvage Logging ◽  
Positive Effects ◽  
Creek Watershed

Abstract. The Baker Creek watershed (1570 km2), situated in the central interior of British Columbia, Canada, has been severely disturbed by both logging and natural disturbance, particularly by a recent large-scale mountain pine beetle (MPB) infestation (up to 2009, 70.2% of the watershed area had been attacked by MPB) and subsequent salvage logging. The concept of equivalent clear-cut area (ECA) was used to indicate the magnitude of forest disturbance, with consideration of hydrological recovery following various types of disturbance (wildfire, logging and MPB infestation), cumulated over space and time in the watershed. The cumulative ECA peaked at 62.2% in 2009. A combined approach of statistical analysis (i.e. time series analysis) and graphic method (modified double mass curve) was employed to evaluate the impacts of forest disturbance on hydrology. Our results showed that severe forest disturbance significantly increased annual mean flow. The average increment in annual mean flow caused by forest disturbance was 48.4 mm yr−1, while the average decrease in annual mean flow caused by climatic variability during the same disturbance period was 35.5 mm yr−1. The opposite changes in directions and magnitudes clearly suggest an offsetting effect between forest disturbance and climatic variability, with the absolute influential strength of forest disturbance (57.7%) overriding that from climate variability (42.3%). Forest disturbance also produced significant positive effects on low flow and dry season (fall and winter) mean flow. Implications of our findings for future forest and water resources management are discussed in the context of long-term watershed sustainability.

scholarly journals The cumulative effects of forest disturbance on streamflow in a large watershed in the central interior of British Columbia, Canada

2012 ◽  
Vol 9 (3) ◽  
pp. 2855-2895 ◽  
Author(s):  
M. Zhang ◽  
X. Wei
Keyword(s):  
British Columbia ◽  
Large Scale ◽  
Mountain Pine Beetle ◽  
Forest Disturbance ◽  
Climatic Variability ◽  
Natural Disturbance ◽  
Low Flow ◽  
Mean Flow ◽  
Salvage Logging ◽  
Creek Watershed

Abstract. The Baker Creek watershed (1570 km2) situated in the central interior of British Columbia, Canada has been severely disturbed by both human-being logging and natural disturbance, particularly by a recent large-scale mountain pine beetle (MPB) infestation (up to 2009, 70.2% of the watershed area was attacked by MPB) and subsequent salvage logging. The concept of equivalent clear-cut area (ECA) was used to indicate the magnitude of forest disturbance with consideration of hydrological recovery following various types of disturbances (wildfire, logging and MPB infestation) cumulated over space and time in the studied watershed. The cumulative ECA was up to 62.2% in 2009. A combined approach of statistical analysis (time series analysis) with modified double mass curve was employed to evaluate the impacts of forest disturbance on hydrology. Our results showed that severe forest disturbance significantly increased annual mean flow. The average increment in annual mean flow caused by forest disturbance was 48.4 mm yr−1, while the average decrease in annual mean flow caused by climatic variability during the same disturbance period was −35.5 mm yr−1. The opposite change directions and magnitudes clearly suggest offsetting effect between forest disturbance and climatic variability, with the absolute influential strength of forest disturbance (57.7%) overriding that from climate variability (42.3%). Forest disturbances also produced significant positive effect on low flow and dry season (fall and winter) mean flow. Implications of our findings for future forest and water resources management are discussed in the context of long-term watershed sustainability.

The cumulative effects of forest disturbance and climate variability on streamflow components in a large forest-dominated watershed

2018 ◽  
Vol 557 ◽  
pp. 448-459 ◽  
Author(s):  
Qiang Li ◽  
Xiaohua Wei ◽  
Mingfang Zhang ◽  
Wenfei Liu ◽  
Krysta Giles-Hansen ◽  
...  
Keyword(s):  
Climate Variability ◽  
Forest Disturbance ◽  
Cumulative Effects

scholarly journals Multiple Venous Malformations with Phleboliths: Radiological-Pathological Correlation

2013 ◽  
Vol 3 ◽  
pp. 13 ◽  
Author(s):  
Venkateswara Rao Chava ◽  
Ashwini Naveen Shankar ◽  
Naveen Shankar Vemanna ◽  
Sudheer Kumar Cholleti
Keyword(s):  
Head And Neck ◽  
Clinical Symptoms ◽  
Vascular Malformations ◽  
High Flow ◽  
The Body ◽  
Low Flow ◽  
Venous Malformations ◽  
Congenital Lesions ◽  
The Face ◽  
Histopathologic Findings

Vascular malformations are congenital lesions that are present at birth and do not regress. However, they often present later in life. They are subdivided into two categories: (1) slow- or low-flow and (2) fast- or high-flow malformations. Low-flow malformations contain combinations of capillary, venous, and lymphatic components. Venous malformations can occur anywhere in the body, but are most frequently seen in the head and neck (40%). These lesions present in a variety of ways, from a vague blue patch to a soft blue mass, which may be single isolated or may occur in multiple areas. Treatment depends on the type of lesion, the location, degree of involvement, and the clinical symptoms. Here we are report the imaging and histopathologic findings in a patient with multiple venous malformations affecting the left side of the face and trunk.

Nationwide hydrological statistics for Sweden with high resolution using the hydrological model S-HYPE

2013 ◽  
Vol 45 (3) ◽  
pp. 349-356 ◽  
Author(s):  
Marie Bergstrand ◽  
Sara-Sofia Asp ◽  
Göran Lindström
Keyword(s):  
Hydrological Model ◽  
Gumbel Distribution ◽  
Cost Effective ◽  
High Flow ◽  
Low Flow ◽  
Small Scale ◽  
Mean Flow ◽  
Low Flows ◽  
Kolmogorov Smirnov ◽  
Regulation Strategies

A first version of nationally covering hydrological statistics for Sweden based on the S-HYPE hydrological model for the period 1961–2010 is described. A key feature of the proposed method is that observed data are used as input wherever such data are available, and the model is used for interpolation in between stations. Short observation records are automatically extended by the use of the model. High flow statistics typically differed by about ±10% from observations. The corresponding number for low flow was about ±30%. High flow peaks were usually simulated slightly too low whereas low flows were too high. In a relative sense low flows were more uncertain than high flows. The mean flow was relatively certain. The annual maximum values were fitted to a Gumbel distribution, by the method of moments, for each subbasin. Flood statistics were then calculated up to a return period of 50 years. According to a Kolmogorov–Smirnov test, less than 1% of the fitted distributions were rejected. Most rejections occurred in regulated systems, due to difficulties in simulating regulation strategies, but also due to uncertainties in the precipitation input in the mountainous region. Results at small scale are very uncertain. The proposed method is a cost-effective way of calculating hydrological statistics with high spatial resolution.

scholarly journals Climate change and its impacts on river discharge in two climate regions in China

2015 ◽  
Vol 12 (7) ◽  
pp. 7099-7126
Author(s):  
H. Xu ◽  
Y. Luo
Keyword(s):  
Climate Change ◽  
River Discharge ◽  
Climate Change Impacts ◽  
High Flow ◽  
Assessment Tools ◽  
Low Flow ◽  
Climate Projections ◽  
Seasonal Temperature ◽  
Mean Flow ◽  
Pronounced Increase

Abstract. Understanding the heterogeneity of climate change and its impacts on annual and seasonal discharge, and the difference between mean flow and extreme flow in different climate regions is of utmost importance to successful water management. To quantify the spatial and temporal heterogeneity of climate change impacts on hydrological processes, this study simulated river discharge in the River Huangfuchuan in semi-arid northern China and the River Xiangxi in humid southern China. We assessed the uncertainty in projected discharge for three time periods (2020s, 2050s and 2080s) using seven equally weighted GCMs for the SRES A1B scenario. Climate projections that were applied to semi-distributed hydrological models Soil Water Assessment Tools (SWAT) in both catchments showed trends toward warmer and wetter conditions, particularly for the River Huangfuchuan. Results based on seven GCMs' projections indicated −1.1 to 8.6 and 0.3 to 7.0 °C changes in seasonal temperature and −29 to 139 and −32 to 85 % changes in seasonal precipitation in River Huangfuchuan and River Xiangxi, respectively. The largest increases in temperature and precipitation in both catchments were projected in the spring and winter seasons. The main projected hydrologic impact was a more pronounced increase in annual discharge in the River Huangfuchuan than in the River Xiangxi. Most of the GCMs projected increased discharge in all seasons, especially in spring, although the magnitude of these increases varied between GCMs. Peak flows was projected to appear earlier than usual in River Huangfuchuan and later than usual in River Xiangxi. While the GCMs were fairly consistent in projecting increased extreme flows in both catchments, the increases were of varying magnitude compared to mean flows. For River Huangfuchuan in the 2080s, median flow changed from −2 to 304 %, compared to a −1 to 145 % change in high flow (Q05 exceedence threshold). For River Xiangxi, low flow (Q95 exceedence threshold) changed from −1 to 77 % and high flow changed from −1 to 62 %, while mean flow changed from −4 to 23 %. The uncertainty analysis provided an improved understanding of future hydrologic behavior in the watershed. Furthermore, this study indicated that the uncertainty constrained by GCMs was critical and should always be considered in analysis of climate change impacts and adaptation.

scholarly journals Effects of land use change on discharge of the Paraíba do Sul river

2021 ◽  
Vol 42 ◽  
pp. e53
Author(s):  
Caluan Rodrigues Capozzoli ◽  
Andrea De Oliveira Cardoso
Keyword(s):  
Land Use ◽  
Water Availability ◽  
Forest Cover ◽  
High Flow ◽  
Metropolitan Region ◽  
Low Flow ◽  
Annual Maximum ◽  
Daily Streamflow ◽  
Very High ◽  
Paraíba Do Sul River

The Paraíba do Sul river basin is located in the southeast region of Brazil and across São Paulo, Rio de Janeiro and Minas Gerais states. In addition to the urban and rural population in the basin, Paraíba do Sul River supplies about twelve million people in the Metropolitan Region of Rio de Janeiro, the third-largest metropolitan region in South America. Land-use in the basin is predominantly dairy farming, where inadequate soil management has affected the quality and quantity of water in the basin. In this work, a distributed hydrological model was performed to assess different surface coverage scenarios considering increments of forest cover along to the basin watercourses. The scenarios were compared with the current condition of the basin in terms of annual mean streamflow, annual maximum daily streamflow, and frequency of occurrence of very high and very low flow extremes. The simulations indicate a reduction in the annual mean streamflow rate due to the increase of the cover forest; reduction of annual maximum daily streamflow due to the increase in forest cover. Extreme frequency analysis indicates that increasing forest cover promotes a decrease in very high flow events and an increase in very low flow events during the rainy months of the basin (October to March), however, in the dry months (especially in August) the occurrence of very high flow events increases while very low flow events decrease. These results indicate that although on average and during the rainy season forest cover negatively affects surface water availability in the driest months, when water resources are scarcer, increased forest cover is beneficial for water availability in the basin.

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