scholarly journals Cohesive Channel Response to Watershed Urbanization: Insights from the Sand River, Aiken SC

Water ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3441
Author(s):  
Jessica Sullivan ◽  
Joshua Grubb ◽  
Ronald Willis ◽  
Derek Boozer ◽  
Brooks Flickinger ◽  
...  

Stream channel degradation is among the most widely documented symptoms of urban stream syndrome arising from watershed urbanization. Nevertheless, our present understanding of space and time scales associated with channel response to urbanization is poorly constrained and largely limited to assessments of non-cohesive systems. The purpose of this study is to assess the evolution of a cohesive, ephemeral river channel in response to watershed urbanization. The assessment of historical images document the stable, pre-urbanized channel conditions from 1870 to 1930. Historical assessments revealed a 131% increase in urbanized watershed area from 1930 to 1992, and a minimal increase in urbanized extent from 1992 to 2012. A 2012 lidar dataset was used to generate the modern long-channel profile, to reconstruct cross-channel profiles observed in 2002, and to estimate the volume flux of sediment removed from the channel from 1930 to 1992, and from 1992 to 2012. The long-channel profile reveals incision of up to 35 m in response to urbanization from 1930 to 1992. Cross-channel profiles reveal incision and widening of 2.5 and 3 m, respectively, from 2002 to 2012. Volume flux estimates indicate erosion rates of 9000 m3/yr during the first 62 years of the study period, and a flux of 4000 m3/yr after installation of stormwater control measures in 1992. Collectively, our findings highlight a cohesive channel that has undergone substantial incision and widening at a rate of ~0.20 m/yr since 1930, and the channel continues to adjust. Hence, we contend that the channel has not yet attained a new equilibrium “shape” at 82 years after peak land use change within the watershed, and that the channel will continue to adjust its shape until this new balance is achieved.

2015 ◽  
Vol 40 (3) ◽  
pp. 480-492 ◽  
Author(s):  
Geoff J. Vietz ◽  
Christopher J. Walsh ◽  
Tim D. Fletcher

The urban stream syndrome is an almost universal physical and ecological response of streams to catchment urbanization. Altered channel geomorphology is a primary symptom that includes channel deepening, widening and instability. While the common approach is to treat the symptoms (e.g. modifying and stabilizing the channel), many stream restoration objectives will not be achieved unless the more vexing problem, treating the cause, is addressed in some way. Research demonstrates that the dominant cause of geomorphic change in streams in urban catchments is an altered flow regime and increase in the volume of stormwater runoff. Thus, managers can choose to treat the symptoms by modifying and controlling the channel to accommodate the altered flow regime, or treat the cause by modifying the flow regime to reduce the impact on channel morphology. In both cases treatments must, at the least, explicitly consider hydrogeomorphology—the science of the linkages between various hydrologic and geomorphic processes—to have a chance of success. This paper provides a review of recent literature (2010 to early 2015) to discuss fluvial hydrogeomorphology in the management of streams subject to urbanization. We suggest that while the dominant approach is focused on combating the symptoms of catchment urbanization (that we refer to as channel reconfiguration), there is increasing interest in approaches that attempt to address the causes by using stormwater control measures at a range of scales in the catchment (e.g. flow-regime management). In many settings in the oft-constrained urban catchment, effective management of stream morphology may require multiple approaches. To conclude, we identify five research areas that could inform urban hydrogeomorphology, one of the most challenging of which is the extent to which the volume of excess urban stormwater runoff can be reduced to mitigate the impact on stream geomorphology.


2016 ◽  
Vol 35 (1) ◽  
pp. 412-420 ◽  
Author(s):  
Derek B. Booth ◽  
Allison H. Roy ◽  
Benjamin Smith ◽  
Krista A. Capps

2018 ◽  
Vol 10 (10) ◽  
pp. 3666 ◽  
Author(s):  
Andrew Erickson ◽  
Vinicius Taguchi ◽  
John Gulliver

The methods for properly executing inspection and maintenance of stormwater control measures are often ambiguous and inconsistently applied. This paper presents specific guidelines for inspecting and maintaining stormwater practices involving media filtration, infiltration, ponds, and permeable pavements because these tend to be widely implemented and often unsatisfactorily maintained. Guidelines and examples are based on recent scientific research and practitioner experience. Of special note are new assessment and maintenance methods, such as testing enhanced filtration media that targets dissolved constituents, maintaining proper vegetation coverage in infiltration practices, assessing phosphorus release from pond sediments, and the development of compressed impermeable regions in permeable pavements and their implications for runoff. Inspection and maintenance examples provided in this paper are drawn from practical examples in Northern Midwest USA, but most of the maintenance recommendations do not depend on regional characteristics, and guidance from around the world has been reviewed and cited herein.


2021 ◽  
pp. 118008
Author(s):  
Vera S. Koutnik ◽  
Jamie Leonard ◽  
Joel B. Glasman ◽  
Jaslyn Brar ◽  
Hatice Ceylan Koydemir ◽  
...  

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