Land-Use Impacts on the Hydrogeomorphology of Small Watersheds

Royall, Dan

doi:10.1016/b978-0-12-818234-5.00010-9

Cited by 6 publications

(11 citation statements)

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“…Meanwhile, numerous studies have evaluated the impacts of land use change and climate variability on the rate of bank erosion and accretion in some of the world’s deltaic landscapes, such as the Niger Delta region 12 , the Mekong River Delta 13 , 14 , and the Yangtze River Delta 15 . In corroboration, Royall et al 16 and Johnson and Royall 17 observed that urbanisation contributes to the alteration of stream channels’ dynamic equilibrium by modifying their response to hydrological and meteorological variables. The outcome of the stream channel modification increases the frequency and magnitude of flood discharge that ultimately leads to bank erosion, channel incision and aggradation 16 , 17 , whereas rapid changes in land use patterns alter the response of streams and river channels to hydrogeomorphic disturbance regimes 18 , 19 .…”

Section: Introductionmentioning

confidence: 79%

“…In corroboration, Royall et al 16 and Johnson and Royall 17 observed that urbanisation contributes to the alteration of stream channels’ dynamic equilibrium by modifying their response to hydrological and meteorological variables. The outcome of the stream channel modification increases the frequency and magnitude of flood discharge that ultimately leads to bank erosion, channel incision and aggradation 16 , 17 , whereas rapid changes in land use patterns alter the response of streams and river channels to hydrogeomorphic disturbance regimes 18 , 19 . However, there is sparse research to date on the linkages between bank erosion and accretion rates, especially in small, rapidly evolving peri-urban watersheds 67 .…”

Section: Introductionmentioning

confidence: 79%

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An integrated assessment of land use impact, riparian vegetation and lithologic variation on streambank stability in a peri-urban watershed (Nigeria)

Okeke

Uno

Academe

et al. 2022

Sci Rep

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Bank erosion is an important source of sediment and phosphorus to inland fluvial systems and is generally responsible for more than half of the total watershed sediment export. Numerous studies have quantified bank erosion and the spatio-temporal variation of sediment flux in different watersheds. However, there is sparse research to date on the linkages between bank erosion/accretion and sediment export under different land uses, especially in rapidly evolving peri-urban watersheds. This research, therefore, integrated remote sensing techniques and repeated field survey of erosion pin plots to quantify bank erosion and sediment flux in the 80 km2 Nkisi River watershed (NRW), southeast Nigeria, over a three-year period. The impact of land use change on streambank erosion was evaluated by utilising remotely sensed Landsat datasets of 2003, 2010, 2016 and 2019. Geotechnical tests were used to characterise the lithologic properties of the banks, while the Bank Stability and Toe Erosion Model (BSTEM) was used to determine the stability of the banks under various hydrological conditions and mechanical properties of the riparian vegetation. Mean bank recession rates increased from 10.7 cm during the 2017–2018 monitoring period to 17.5 cm for the 2019–2020 monitoring period. The percentage of total watershed export ascribed to bank erosion in the three stream reaches varied from 6.6 to 44.9%. The high rates of bank erosion and accretion within the NRW were attributed to rapid changes in land use, which evolved from grassland and woodland to cropland, built-up and bare land. The BSTEM accurately predicted the high erosion rates of the streambanks and showed that riparian vegetation has a mechanical effect on bank stability. However, the mechanical effect diminishes as the depth to water table rises during high streamflow events.

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Section: Introductionmentioning

confidence: 79%

Section: Introductionmentioning

confidence: 79%

An integrated assessment of land use impact, riparian vegetation and lithologic variation on streambank stability in a peri-urban watershed (Nigeria)

Okeke

Uno

Academe

et al. 2022

Sci Rep

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“…Landscape modifications that decrease infiltration will impose changes to river hydrology (Ghunowa et al, 2021;Ashmore, 2015;Taniguchi & Biggs, 2015;Winter, 2001) with a downstream cascading effect on flow regime (Royall, 2013). Human occupation, landscape manipulation, and the generation of impervious surfaces associated with urbanization have the most profound impact on hydrogeomorphic responses, particularly in smaller watersheds (Pasternack, 2013;Royall, 2013). And a fluvial system's response to human-induced land use change (or its sensitivity to change) will vary, depending on basin attributes (i.e., configuration, geomorphology, and sediment retention) (Royall, 2013).…”

Section: Introductionmentioning

confidence: 99%

“…Human occupation, landscape manipulation, and the generation of impervious surfaces associated with urbanization have the most profound impact on hydrogeomorphic responses, particularly in smaller watersheds (Pasternack, 2013;Royall, 2013). And a fluvial system's response to human-induced land use change (or its sensitivity to change) will vary, depending on basin attributes (i.e., configuration, geomorphology, and sediment retention) (Royall, 2013). For this reason, the spatial heterogeneity across a landscape will likely produce a variation in flood response that may best be captured using an RFFA approach with multi-variate analysis that considers relevant parameterized basin characteristics (i.e., topographic relief, land use, vegetation, and subsurface geology) as a set of explanatory variables to estimate flood discharge (Ahn & Palmer, 2016).…”

Section: Introductionmentioning

confidence: 99%

Modelling flood frequency and magnitude in glacially conditioned settings: land use matters

Tetford¹,

Desloges²

2023

Preprint

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Abstract. A reliable flood frequency analysis (FFA) requires selection of an appropriate statistical distribution to model historic streamflow data and, where streamflow data are not available (ungauged sites), a regression-based regional flood frequency analysis (RFFA) often correlates well with downstream channel discharge to drainage area relations. However, the predictive strength of the accepted RFFA relies on an assumption of homogeneous watershed conditions. For glacially conditioned fluvial systems, inherited glacial landforms, sediments, and variable land use can alter flow paths and modify flow regimes. This study compares a multi-variate RFFA that considers 28 explanatory variables to characterize variable watershed conditions (i.e., surficial geology, climate, topography, and land use) to an accepted power-law relationship between discharge and drainage area. Archived gauge data from southern Ontario, Canada are used to test these ideas. Mathematical goodness-of-fit criteria best estimate flood discharge for a broad range of flood recurrence intervals, i.e., 1.25, 2, 5, 10, 25, 50, and 100 years. The LN, EV1, LP3, and GEV distributions are found most appropriate in 42.5 %, 31.9 %, 21.7 %, and 3.9 % of cases, respectively, suggesting that systematic model selection criterion is required for FFA in heterogeneous landscapes. Multi-variate regression of estimated flood quantiles with backward elimination of explanatory variables using principal component and discriminant analyses reveal that precipitation provides a greater predictive relationship for more frequent flood events, whereas surficial geology demonstrates more predictive ability for high magnitude, less frequent flood events. In this study, all seven flood quantiles identify a statistically significant two-predictor model that incorporates upstream drainage area and the percentage of naturalized landscape with 5 % improvement in predictive power over the commonly used single-variable drainage area model (p < 2.2e−16). An analysis of variance (ANOVA) further supports the two-predictor model indicating a decrease in the sum of squares of residuals and an F statistic (p < 0.001) that demonstrates very strong evidence in favour of the two-predictor model (i.e., drainage area and land use) when estimating flood discharge in this low-relief landscape with pronounced glacial legacy effects and heterogenous land use.

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“…This gap in research is despite our observations that small streams are often the most likely to be impacted by development—perhaps because a lack of research or gauging makes it easier for them to be labelled as intermittent. Furthermore, small watersheds often have heightened connectivity between landscape and stream (Royall, 2021), potential for higher unit stream power (Beschta & Platts, 1986), and/or shorter lag times. Because of their small size, headwater streams experience more direct effects of land use change, which can have significant environmental impacts in individual streams (e.g., Gage et al, 2004) and on the rest of the stream system (e.g., Alexander et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

Seasonal flashiness and high frequency discharge events in headwater streams in the North Carolina Piedmont (United States)

Johnson

Morris

Mase

et al. 2022

Hydrological Processes

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First‐order streams are rarely the focus of research even though they play an important hydrological and ecological role in upland landscapes and may be more susceptible to human impacts than larger streams. We studied 16 first‐order streams in the North Carolina Piedmont to examine relationships between land use, discharge, flashiness and conductivity in the headwaters of the Rocky River and McDowell Creek. Stream gauges were installed on each of the 16 headwater streams to provide constant monitoring of stream depth, temperature and specific conductance. Rating curves were created for each site using models that combined field measured and Manning's calculated discharge. Initial attempts to measure flashiness using the Richards‐Baker Index (RBI) indicated that it is not a good proxy for flashiness in small streams because its use of median daily flows do not capture fluctuations that occur over short time periods. Instead, we developed a new method that focused on the number of days each stream flows above its 99th percentile flow (DMQ99). We also examined individual storm events across multiple seasons. We found that headwater streams in the Piedmont are flashier than more commonly gauged second and third order streams because first‐order streams are more directly connected to the landscape. Streams located in suburban areas tend to be flashier than streams in forested areas as a result of the increase in impervious surfaces and the reduction of evapotranspiration (ET) caused by development. Additionally, we found that all streams become flashier in the winter when ET is lower, suggesting important feedbacks between physical and biological systems. All streams experience periodic extreme conductivity events, indicating significantly impaired ecological conditions. More developed basins generally have higher maximum specific conductance compared with less developed basins although streams have significant natural variability as well. Overall, our results indicate that first‐order streams in the Piedmont are highly impacted by development and that extra caution should be exercised when altering landscapes near small streams.

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Land-Use Impacts on the Hydrogeomorphology of Small Watersheds

Cited by 6 publications

References 205 publications

An integrated assessment of land use impact, riparian vegetation and lithologic variation on streambank stability in a peri-urban watershed (Nigeria)

An integrated assessment of land use impact, riparian vegetation and lithologic variation on streambank stability in a peri-urban watershed (Nigeria)

Modelling flood frequency and magnitude in glacially conditioned settings: land use matters

Seasonal flashiness and high frequency discharge events in headwater streams in the North Carolina Piedmont (United States)

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