Exploring the potential for using hierarchical sediment fingerprinting as an urban management tool in monitoring changing sediment sources

2020 ◽  
Author(s):  
Rory Walsh ◽  
Carla Ferreira ◽  
William Blake ◽  
Sam Higton ◽  
Antonio Ferreira
Keyword(s):  
Land Use ◽  
Suspended Sediment ◽  
Agricultural Land ◽  
Management Tool ◽  
Sediment Fingerprinting ◽  
Storm Events ◽  
Sediment Sources ◽  
Wet Season ◽  
Stream Network ◽  
Urban Catchments

<p>An ability to identify and quantify changes in sediment sources and erosion within catchments would be of great use for landscape managers and planners. This is particularly the case in peri-urban catchments, which are characterized by complex and dynamically changing land-use mosaics – and where today’s planning decisions may be crucial as regards avoiding or exacerbating erosional, water quality and flooding problems. This study explores the potential for a sediment fingerprinting approach to provide a cost-effective way of assessing changes in sediment sources within a small peri-urban catchment. The study focuses on the Ribeira dos Covões catchment (6.2 km<sup>2</sup>), on the outskirts of Coimbra in central Portugal. The climate is humid Mediterranean and the geology is 56% sandstone, 41% marly limestone and 3% alluvium. Current land-use is 56% woodland, 4% agricultural and 40% urban (mainly residential, but also a recently constructed enterprise park (5%) and major highway (1%)). Recent urbanization has largely occupied former agricultural land. The study adopts a multi-proxy sediment fingerprinting approach, based on geochemical (elemental) characterization of fluvial fine bed-sediment and soil samples, using a Niton x-ray fluorescence elemental analyser. Sampling of fluvial sediment was carried out at 33 sites within the stream network (including all significant tributaries, downstream sites and the catchment outlet). Samples were collected in July 2018 and November 2018 following contrasting ‘late wet season’ and ‘end of dry season’ events. In addition, in July 2018 composite samples of potential sediment sources were collected, including (i) soil surface (0-2cm) samples at 64 representative locations, (ii) 17 samples from eroding channel margin sites, and (iii) 15 samples of road sediment. All samples were sieved to obtain <63µm, 63-125µm, 125-250 µm and 250-2000µm fractions, where the <63µm fraction was taken to represent suspended sediment. The elemental geochemistry of each sample fraction was derived using the XRF analyser. Differences (and similarities) in geochemical signatures between the various tributaries and the various potential sources were assessed using a range of statistical techniques. Bayesian unmixing models were used in a hierarchical (confluence-based) fashion to assess the contributions of different sub-catchments to downstream sites including the catchment outlet. Modelling results were then compared with relative contributions for three previously analysed storm events of 2012-2015, at which time construction activities had been more active. Modelling results for the two 2018 events were also validated by comparing them with independent suspended sediment records collected at five locations on the principal tributaries and at the catchment outlet. Overall, the modelling was successful in indicating and quantifying significant changes in sediment sources through time within the catchment. Reasons as to why sediment fingerprinting was successful in this case are then examined and discussed, in part drawing comparisons with the findings from a parallel sediment fingerprinting study of changing sources in the dynamically changing partly logged rainforest, partly oil palm Brantian catchment in Sabah, Malaysian Borneo. The potential for a simple sediment fingerprinting methodology to be developed for more widespread use by urban/environmental managers and planners is then explored.  </p>

Multi-fractional sediment fingerprinting in monitoring sediment sources in a peri-urban Portuguese catchment

2021 ◽  
Author(s):  
Rory Walsh ◽  
Carla Ferreira ◽  
William Blake ◽  
Sam Higton ◽  
Antonio Ferreira
Keyword(s):  
Particle Size ◽  
Suspended Sediment ◽  
Agricultural Land ◽  
Size Fraction ◽  
Soil Samples ◽  
Sediment Fingerprinting ◽  
Bed Sediment ◽  
Sediment Sources ◽  
Geochemical Composition ◽  
Size Fractions

<p>This paper explores the potential for using multiple particle size fractions in a hierarchical geochemical sediment fingerprinting approach to the assessment of changes in sediment sources through time within a small Mediterranean peri-urban catchment. Conventional  sediment fingerprinting has focussed on the <63µm fraction of fine bed-sediment on the basis that this fraction represents suspended sediment, which in turn is considered dominant over bedload in catchment sediment budgets. In reality, however, coarser sediment than 63µm may form part of suspended sediment and/or occurs as relatively fast-moving fine bedload.  Furthermore, sediment sources vary in their particle size distribution and, as geochemical composition can vary with particle size, it is arguable that sediment fingerprinting studies should consider use of multiple size fractions.</p><p>This study explores this approach using <63µm, 63-125µm, 125-250 µm and 250-2000µm size fractions.  It focuses on the north-south flowing Ribeira dos Covões catchment (6.2 km<sup>2</sup>), on the outskirts of Coimbra in central Portugal. The climate is humid Mediterranean. Catchment geology is 56% sandstone (in the east), 41 % marly limestone (in the west) and 3 % alluvium. Current land-use is 56% woodland, 4 % agricultural and 40% urban (mainly residential, but also including a recently constructed enterprise park (5%) and major highway (1%)). Recent urbanization has largely occupied former agricultural land. </p><p>The study adopts a multi-proxy sediment fingerprinting approach to assessment of changes in sediment sources, based on geochemical (elemental) characterization of the four different size fractions of fluvial bed-sediment and soil samples, using a Niton x-ray fluorescence (XRF) elemental analyser. Sampling of fluvial sediment was carried out at 33 sites within the stream network (including all significant tributaries, downstream sites and the catchment outlet). Samples were collected in July 2018 and November 2018 following contrasting ‘late-wet-season’ and ‘end-of-dry-season’ events. In July 2018, samples of potential sediment sources were collected including: (i) soil surface (0-2cm) samples at 64 locations, (ii) 17 samples from eroding channel margin sites, and (iii) 15 samples of road sediment. All fluvial and soil samples were sieved to obtain the four target size fractions. The elemental geochemistry of each sample fraction at all fluvial and source sites was derived using the XRF analyser.  (These results were added to similar datasets previously obtained on three occasions in 2012-15 in a period of enhanced urban constructional disturbance). Differences (and similarities) in geochemical signatures between the different size fractions at each survey date at and between each tributary and potential source site were assessed using a range of statistical techniques.  Messages arising are discussed. For each size fraction and survey date, Bayesian unmixing models were used in a hierarchical (confluence-based) fashion to assess the contributions of sub-catchments to downstream sites and the catchment outlet. Modelling results for the two 2018 events were validated by comparing them with suspended sediment records collected at five tributary locations and at the catchment outlet.  Although overall, the modelling was successful in indicating and quantifying significant changes in sediment sources through time within the catchment, uncertainties in interpretation of the multiple fractions are identified and discussed. </p>

scholarly journals The Long-Term Effects of Land Use and Climate Changes on the Hydro-Morphology of the Reno River Catchment (Northern Italy)

Water ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1831 ◽  
Author(s):  
Donatella Pavanelli ◽  
Claudio Cavazza ◽  
Stevo Lavrnić ◽  
Attilio Toscano
Keyword(s):  
Land Use ◽  
Suspended Sediment ◽  
Flow Rate ◽  
Sediment Yield ◽  
River Flow ◽  
Agricultural Land ◽  
Single Channel ◽  
Northern Italy ◽  
Lulc Changes ◽  
Suspended Sediment Yield

Anthropogenic activities, and in particular land use/land cover (LULC) changes, have a considerable effect on rivers’ flow rates and their morphologies. A representative example of those changes and resulting impacts on the fluvial environment is the Reno Mountain Basin (RMB), located in Northern Italy. Characterized by forest exploitation and agricultural production until World War II, today the RMB consists predominantly of meadows, forests and uncultivated land, as a result of agricultural land abandonment. This study focuses on the changes of the Reno river’s morphology since the 1950s, with an objective of analyzing the factors that caused and influenced those changes. The factors considered were LULC changes, the Reno river flow rate and suspended sediment yield, and local climate data (precipitation and temperature). It was concluded that LUCL changes caused some important modifications in the riparian corridor, riverbed size, and river flow rate. A 40–80% reduction in the river bed area was observed, vegetation developed in the riparian buffer strips, and the river channel changed from braided to a single channel. The main causes identified are reductions in the river flow rate and suspended sediment yield (−36% and −38%, respectively), while climate change did not have a significant effect.

scholarly journals Agriculture Land Use Change and Demographic Change in Response to Decline Suspended Sediment in Južna Morava River Basin (Serbia)

2021 ◽  
Vol 13 (6) ◽  
pp. 3130
Author(s):  
Sanja Manojlović ◽  
Mikica Sibinović ◽  
Tanja Srejić ◽  
Abosa Hadud ◽  
Ibrahim Sabri
Keyword(s):  
Land Use ◽  
Sediment Transport ◽  
Land Use Change ◽  
Suspended Sediment ◽  
Human Activities ◽  
Rural Population ◽  
Agricultural Land ◽  
Sediment Load ◽  
Morava River ◽  
Morava River Basin

This study expounds the dynamic relationships among agricultural land-use change, rural population migration, and sediment transport. The variability of suspended sediment load was detected by Mann–Kendall and Pettitt tests. From 1961 to 2007, the annual trend in suspended sediment concentration and sediment load demonstrated significant reduction (α = 0.001), with decreasing rates of 0.0144 g/L/y and 84.7 t/y, respectively. An abrupt change-point was detected in 1984 for the sediment load (p = 0.0001). The double-mass curve method and regression analysis of sediment load versus precipitation were used to quantify the effects of climate change and human activities on sediment load variations. The changes in sediment load were predominantly impacted by human activities (89%), while precipitation explained 11% of the reduction in suspended sediment. An important land-use change recorded in the Južna Morava river basin comprised the abandonment of agricultural lands due to depopulation processes, as well as economic and social changes, which was followed by significant impacts on soil erosion and sediment transport. Land abandonment was most pronounced in marginal mountain or semi-mountainous areas, where agriculture was until recent decades traditional or semi-traditional. The results of the correlation matrix were significant at the p < 0.05 level, demonstrating that the decrease of rural population, agricultural land, and arable land were directly related to the decline of suspended sediment. High correlation coefficients were found between anthropogenic indicators and sediment parameters, ranging from 0.94 to 0.97.

scholarly journals Plants or bacteria? 130 years of mixed imprints in Lake Baldegg sediments (Switzerland), as revealed by compound-specific isotope analysis (CSIA) and biomarker analysis

2018 ◽  
Author(s):  
Marlène Lavrieux ◽  
Axel Birkholz ◽  
Katrin Meusburger ◽  
Guido L. B. Wiesenberg ◽  
Adrian Gilli ◽  
...  
Keyword(s):  
Land Use ◽  
Lake Sediment ◽  
Agricultural Land ◽  
Isotope Analysis ◽  
Bacterial Biomass ◽  
Land Uses ◽  
Sediment Sources ◽  
Pentacyclic Triterpenoids ◽  
Compound Specific Isotope Analysis ◽  
Biomarker Analysis

Abstract. Soil erosion and associated sediment transfer are among the major causes of aquatic ecosystem and surface water quality impairment. Through land-use and agricultural practices, human activities modify the soil erosive risk and the catchment connectivity, becoming a key factor of sediment dynamics. Hence, restoration and management plans of water bodies can only be efficient if the sediment sources and the proportion attributable to different land-uses are identified. To this aim, we applied two approaches, namely compound-specific isotope analysis (CSIA) of long-chain fatty acids (FA) and triterpenoid biomarker analysis, to the eutrophic Lake Baldegg and its agriculturally used catchment (Switzerland). Soils reflecting the five main land-uses of the catchment (arable lands, temporary and permanent grasslands, mixed forests, orchards) were subjected to CSIA. The compound-specific stable isotope δ13C signatures clearly discriminate between grasslands (permanent and temporary) and forests. Signatures of agricultural land and orchards fall in-between. The soil signal was then compared to the isotopic signature of a lake sediment sequence covering ca. 130 years (before 1885 to 2009). Most of the lake sediment samples lie out of the source soils polygon, most likely as a result of carbon exchanges with highly depleted material related to methanotrophic bacterial activity. The recent lake samples falling into the soil polygon indicate an important contribution of the forests, which can be explained by (1) the location of the forests on steep slopes, resulting in a higher connectivity of the forests to the lake, and (2) potential direct inputs of trees and shrubs growing along the rivers feeding the lake and around the lake. Despite the strong bacterial overprint on the isotopic signal, land-use and catchment history are clearly reflected in the CSIA results, with isotopic shifts being consistent with catchment, land-use and eutrophication history. While present in the soils, the investigated highly specific biomarkers were not detected in the lake sediment. Two trimethyltetrahydrochrysenes (TTHCs), natural diagenetic products of pentacyclic triterpenoids, were found in the lake sediments. Their origin is attributed to the in-situ microbial degradation of some of the triterpenoids. While the need to apportion sediment sources is especially crucial in eutrophic systems, our study stresses the importance of using caution with CSIA and triterpenoid biomarkers in such environments, where the presence of methanotrophic bacterial biomass might overprint original isotopic signals.

Influence of climate,geology and humans on spatial and temporal nutrient geochemistry in the subtropical Richmond River catchment, Australia

2001 ◽  
Vol 52 (2) ◽  
pp. 235 ◽  
Author(s):  
Lester J. McKee ◽  
Bradley D. Eyre ◽  
Shahadat Hossain ◽  
Peter R. Pepperell
Keyword(s):  
Water Quality ◽  
Land Use ◽  
Agricultural Land ◽  
Anthropogenic Impacts ◽  
Inorganic Nitrogen ◽  
Point Sources ◽  
Nutrient Concentrations ◽  
Wet Season ◽  
Nitrogen And Phosphorus ◽  
River Catchment

Water quality was monitored on a spatial and temporal basis in the subtropical Richmond River catchment over two years. Nutrient concentrations varied seasonally in a complex manner with highest concentrations (maximum =3110 µg N L – 1 and 572 µg P L –1 ) associated with floods. However, median (444 µg N L – 1 and 55 µg P L – 1 ) concentrations were relatively low compared with other parts of the world. The forms of nitrogen and phosphorus in streams varied seasonally, with greater proportions of inorganic nitrogen and phosphorus during the wet season. Minimum nutrient concentrations were found 2—3 months after flood discharge. With the onset of the dry season, concentration increases were attributed to point sources and low river discharge. There were statistically significant relationships between geology and water quality and nutrient concentrations increased downstream and were significantly related to population density and dairy farming. In spite of varying geology and naturally higher phosphorus in soils and rocks in parts of the catchment, anthropogenic impacts had the greatest effects on water quality in the Richmond River catchment. Rainfall quality also appeared to be related both spatially and seasonally to human activity. Although the responses of the subtropical Richmond River catchment to changes in land use are similar to those of temperate systems of North America and Europe, the seasonal patterns appear to be more complex and perhaps typical of subtropical catchments dominated by agricultural land use.

Improving spatial representation of erosion sources using Sediment Fingerprinting with terrain data and sediment budget modelling

2020 ◽  
Author(s):  
Simon Vale ◽  
Hugh Smith
Keyword(s):  
Suspended Sediment ◽  
Source Apportionment ◽  
End Users ◽  
Sediment Budget ◽  
Storm Event ◽  
Sediment Source ◽  
Sediment Fingerprinting ◽  
Sediment Sources ◽  
Geochemical Tracers ◽  
Source Contributions

&lt;p&gt;Sediment fingerprinting quantifies proportional contributions of catchment sediment sources to downstream sediment mixtures and deposits. While the sediment fingerprinting technique is well established it is still challenged by the coarse spatial resolution of sediment source discrimination which hinders understanding of catchment sediment dynamics and limits its usefulness for land management where finer resolution spatial information is required.&lt;/p&gt;&lt;p&gt;Here, two conventional sediment fingerprinting datasets from New Zealand are used to show how spatial modelling of source loads can improve 1) the usefulness of sediment fingerprinting approaches and 2) visualization of results for end-users by combining source apportionment with terrain information and sediment budget modelling. The two case studies involve unmixing sediment source contributions to 1) overbank deposits within the Oroua River catchment, where six sediment sources (Mountain Range, Mudstone, Hill Subsurface, Hill Surface, Unconsolidated Sandstone, and Channel Bank) across two size fractions (&lt;63 &amp;#181;m and 125&amp;#8211;300 &amp;#181;m) were characterized using bulk geochemical and radionuclide tracers and 2) suspended sediment in the Manawatu catchment, where a similar six sources were characterized using bulk geochemical tracers to determine changes in source contributions to hourly suspended sediment samples during a 53hr storm event.&lt;/p&gt;&lt;p&gt;The proportional source contributions for each case study are applied to modelled sediment loads and spatially distributed using terrain information for rock type, slope and channel network extent to produce specific sediment yield maps for both catchments and spatial visualization of sediment generation during the Manawatu catchment storm event. Integrating sediment fingerprinting results with spatial datasets and modelling can enhance interpretation of source apportionment results and improve the utility of this information for end-users focused on the spatial targeting of erosion sources for mitigation to reduce downstream sediment impacts.&amp;#160; &amp;#160;&lt;/p&gt;

scholarly journals Using sustainability indicators in agricultural land use analysis: an example from Costa Rica

1995 ◽  
Vol 43 (1) ◽  
pp. 61-82 ◽  
Author(s):  
D.M. Jansen ◽  
J.J. Stoorvogel ◽  
R.A. Schipper
Keyword(s):  
Land Use ◽  
Costa Rica ◽  
Agricultural Land ◽  
Programming Model ◽  
Sustainability Indicators ◽  
Geographical Information ◽  
Management Tool ◽  
Agricultural Land Use ◽  
Sustainability Concept ◽  
Quantitative Indicators

A methodology to analyse land use is applied to the Neguev settlement in the Atlantic Zone of Costa Rica. The methodology comprises a linear programming model, a geographical information system, and a customized data management tool. While options for land use are described at the field level, the methodology allows for analysis of land use at the field, the farm and the regional level. The various steps involved in making the sustainability concept operational are described. Selection and quantification of the sustainability indicators require some assumptions, affecting the period for which the analysis can assumed to be valid. The possibility of using nutrient balances and biocide indices as quantitative indicators of sustainability of agricultural land use systems is argued and demonstrated for the Neguev settlement. Some limitations and advantages of the methodology are discussed.

scholarly journals Influence of agricultural land-use and pesticides on benthic macroinvertebrate assemblages in an agricultural river basin in southeast Brazil

2012 ◽  
Vol 72 (3) ◽  
pp. 437-443 ◽  
Author(s):  
M Egler ◽  
DF. Buss ◽  
JC. Moreira ◽  
DF. Baptista
Keyword(s):  
Land Use ◽  
Agricultural Land ◽  
Intensive Agriculture ◽  
Benthic Macroinvertebrate ◽  
Land Uses ◽  
Wet Season ◽  
Macroinvertebrate Assemblages ◽  
Lower Complexity ◽  
Agricultural Areas ◽  
Macroinvertebrate Fauna

Land-use alterations and pesticide run-offs are among the main causes for impairment in agricultural areas. We evaluated the influence of different land-uses (forest, pasture and intensive agriculture) on the water quality and on benthic macroinvertebrate assemblages on three occasions: in the dry season, wet season and at the end of the wet season. Macroinvertebrates responded to this gradient of impairment: agricultural sites had significantly lower richness numbers than forested and pasture sites, and all major invertebrate groups were significantly affected. Most taxa found in forested sites were found in pasture sites, but often with lower densities. In this case, the loss of habitats due to sedimentation and the lower complexity of substrates seem to be the disruptive force for the macroinvertebrate fauna.

scholarly journals Impact of Land-Use Changes on Spatiotemporal Suspended Sediment Dynamics within a Peri-Urban Catchment

Water ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 665 ◽  
Author(s):  
C.S.S. Ferreira ◽  
R.P.D. Walsh ◽  
Z. Kalantari ◽  
A.J.D. Ferreira
Keyword(s):  
Land Use ◽  
Suspended Sediment ◽  
Urban Area ◽  
Land Use Changes ◽  
Suspended Sediments ◽  
Sediment Dynamics ◽  
Storm Event ◽  
Rainfall Condition ◽  
Urban Catchments ◽  
The Impact

Understanding sediment dynamics in peri-urban catchments constitutes a research challenge because of the spatiotemporal complexity and variability of land-uses involved. This study investigates differences in the concentration of total sediments (TSC) and suspended sediments (SSC) in the small peri-urban Mediterranean Ribeira dos Covões catchment (40% urban area) in central Portugal. Suspended sediment responses at the catchment outlet (E) and in three upstream sub-catchments, during periods of urbanization (2011–2013) and stabilizing land-use (2017–2018) are compared for storm-event datasets encompassing similar ranges of rainstorm sizes and antecedent rainfall condition. The Quinta sub-catchment, with the lowest urban area (22%) but subject to major construction activities affecting 17% of its area, led to highest TSC and SSC during urbanization (attaining 4320 mg/L and 4184 mg/L, respectively), and a median reduction of 38% and 69%, respectively, during stabilization. Espírito Santo sub-catchment, with highest urban area (49%) and minor construction activities, displayed similar median TSC in both periods (258–240 mg/L) but highest SSC reduction (76%), highlighting the impact of the anthropogenic disturbance mainly on fine-particle sediments and a good connectivity with the stream. Porto Bordalo sub-catchment, with 39% urban area and subject to the construction of a four-line road covering 1.5% of its area, showed the lowest TSC and SSC concentrations and the lowest median reductions in both periods (31% and 64%, correspondingly), mainly because of the impact of an unplanned retention basin established with soil from the construction site. Overall, median TSC and SSC reduced 14% and 59% at E, from urbanization to stabilization. Information about sediment dynamics should guide stakeholders in establishing strategies to reduce sediment loads and mitigate the impacts on urban aquatic ecosystems.

scholarly journals Declining suspended sediment in United States rivers and streams: Linking sediment trends to changes in land use/cover, hydrology and climate

2019 ◽  
Author(s):  
Jennifer C. Murphy
Keyword(s):  
United States ◽  
Land Use ◽  
Suspended Sediment ◽  
Land Management ◽  
Agricultural Land ◽  
Sediment Runoff ◽  
Systematic Change ◽  
Mixed Use ◽  
Main Driver ◽  
Streamflow Regime

Abstract. Between 1992 and 2012, concentrations of annual mean suspended sediment decreased at over half (58 %) of the 137 stream sites assessed across the contiguous United States (US). Increases occurred at 17 % of the sites and the direction of change was uncertain at the remaining 25 %. Sediment trends were characterized using the Weighted Regressions on Time, Discharge, and Season model, and decreases in sediment ranged from −95 % to −8.5 % of the 1992 concentration. To explore potential drivers of these changes, the sediment trends were (1) parsed into two broad contributors of change, changes in land management versus changes in the streamflow regime, and (2) grouped by land use of the watershed and correlated to concurrent changes in land use/cover, hydrology and climate and static/long-term watershed characteristics. At 83 % of the sites, changes in land management (captured by changes in the concentration–streamflow relationship over time) contributed more to the change in the sediment trend than changes in the streamflow regime alone (i.e. any systematic change in the magnitude, frequency or timing of flows). However, at > 60 % of the sites, changes in the streamflow regime contributed at least a 5 % change in sediment and at 10 sites changes in the streamflow regime contributed over half the change in sediment, indicating that at many sites changes in streamflow were not the main driver of changes in sediment but was often an important supporting factor. Correlations between sediment trends and concurrent changes in land use/cover, hydrology and climate were often stronger at sites draining watersheds with more homogenous, human-related land uses (i.e. agricultural and urban lands) compared to mixed-use or undeveloped lands. At many sites, decreases in sediment occurred despite small to moderate increases in the amount of urban or agricultural land in the watershed, suggesting conservation efforts to reduce sediment runoff to streams may be successful, up to a point, even as lands are converted to urban and agricultural uses.

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