scholarly journals Sediment Budgets for Small Salinized Agricultural Catchments in Southwest Australia and Implications for Phosphorus Transport

Water ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 3564
Author(s):  
Robert J. Wasson ◽  
David M. Weaver
Keyword(s):  
Gully Erosion ◽  
Delivery Ratio ◽  
Phosphorus Transport ◽  
Rill Erosion ◽  
Sediment Delivery ◽  
Sediment Storage ◽  
Agricultural Catchments ◽  
Sediment Budgets ◽  
Southwest Australia ◽  
The Impact

Examples of sediment budgets are needed to document the range of budget types and their controls. Sediment budgets for three small agricultural catchments (7.6 to 15.6 km2) in southwestern Australia are dominated by channel and gully erosion, with sheet and rill erosion playing a subordinate role. Erosion was increased by clearing naturally swampy valley floors and hillslopes for agriculture and grazing, and episodic intense rainstorms. The proportion of sediment from channel and gully erosion in the sediment budget appears to be determined by the depth of alluvial fills. Dryland salinization caused by clearing native vegetation has connected hillslopes to channels across narrow floodplains, increasing the Sediment Delivery Ratio (SDR). Yield and SDR are found to be insensitive to major in-catchment changes of vegetation cover after initial clearing, the ratio of sheet and rill erosion/channel and gully erosion, and sediment storage masses. This supports the idea that yield alone is often a poor indicator of the impact of land use and land management change. Riparian vegetation would reduce sediment yield but not phosphorus yield. This study demonstrates the value of mixed methods where field observations and chemical analysis are combined with information from local people.

scholarly journals Catchment Sediment Dynamics and the Role of Deep-Seated Landslide-Dams; Waipaoa Catchment, Raukumara Peninsula, New Zealand

2021 ◽  
Author(s):  
◽  
Richard James Taylor
Keyword(s):  
Sediment Transport ◽  
Large Scale ◽  
Gully Erosion ◽  
Sediment Dynamics ◽  
Storm Events ◽  
14C Dating ◽  
Sediment Delivery ◽  
Ground Shaking ◽  
Landslide Dams ◽  
The Impact

<p>Sediment volumes retained by landslide-dams of the Waipaoa are small at 1.85x10⁶m³ compared to the 24.5km³ (Marden et al., 2008b) of sediment eroded in the landscape since the last glacial maximum. Landslide-dams do however represent a major perturbation to sediment transport, although due to their mainly short life span this disruption is discontinuous representing a pulsing in the transport network. The objective of this study is to investigate the sedimentary dynamics of the Waipaoa catchment by providing insights into the role that deep-seated landslides play and asks the questions: What is the impact on sediment transport imposed by the landslide-dams of the Waipaoa catchment? and; What do the sediments impounded in landslide-dammed lakes tell us about catchment sediment dynamics through time? The Waipaoa River on the East Cape of New Zealand‘s North Island delivers volumes of sediment to the coast which are considered high by global standards. Catchment erosion is controlled by soft marine sediments, combined with a history of tectonic fracturing and frequent intense rain storms. Erosion events are driven by intense cyclonic systems rain storms which deliver ≥200mm/24hr rainfall and induce catchment wide gully erosion as well as shallow surficial landslides. Under current land covers gully erosion provides the dominant source of sediments, with high degrees of slope channel coupling and steep gradient river profiles providing for efficient delivery to the coast. Offshore in the Poverty Bay, sediments delivered by the Waipaoa River show considerable variability over a range of temporal scales. Valley slopes within the Waipaoa catchment are also susceptible to large deep-seated landslide failures, with movement depths greater than 5 metres often on internal structural failure planes. These large slope movements can be produced by both extreme storm events (≥300mm/24hr) which occur on a return periods of 1 in 5 years and seismic ground shaking of 1 in 1000-2000 years. Where these large events block channels and are able to persist for long periods, sediments accumulated upstream to provide a unique record of the catchments sedimentary history. There have been some 1100 historic large scale features which have been identified within the Waipaoa region, with this study selecting seven that have shown evidence of channel blockage. The project aims to provide insights into the age of a sample of deep-seated landslides that have dammed channels to determine how long landslide-dams survive in the landscape and quantify the volumes of sediment they have trapped. Further, the project aims to determine what the spatial and temporal distribution of these blockages has meant to sediment delivery and whether there have been changes in sediment dynamics in their upper catchments over time. The project uses the detailed mapping of the trapped body of sediments, GIS modelling of the palaeo and present landscapes and age control determinations provided by tephra and 14C dating to provide both volumes and rates of sediment delivery.</p>

scholarly journals Land Degradation and Soil Conservation Measures in the Moldavian Plateau, Eastern Romania: A Case Study from the Racova Catchment

Water ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 2877
Author(s):  
Lilian Niacsu ◽  
Ion Ionita ◽  
Claudia Samoila ◽  
Georgel Grigoras ◽  
Ana Maria Blebea-Apostu
Keyword(s):  
Land Degradation ◽  
Soil Conservation ◽  
Field Measurements ◽  
Farming System ◽  
Delivery Ratio ◽  
Sediment Delivery ◽  
Water Storage Capacity ◽  
Conservation Measures ◽  
The Impact ◽  
Soil Conservation Measures

Land degradation by soil erosion, gullying and landslides and reservoir sedimentation is a major environmental threat in the Moldavian Plateau of eastern Romania. The widespread development of these processes in the last two centuries was favored mainly by traditional agriculture focused on ‘up-and-down slope’ farming on small plots. However, soil conservation measures were actively undertaken between 1970 and 1989. More recent legislation (No. 18/1991 Agricultural Real Estate Act) includes two provisions that discourage maintaining and extending soil conservation practices. Hence, the former contour farming system has been abandoned in favor of the traditional, inadequate farming methods. Thus, this paper reviews the impact of land degradation and soil conservation measures in a representative 32,908 ha catchment located in the Central Moldavian Plateau. Based on field measurements, the results show that the estimated mean long-term (1973–2017) sedimentation rate reaches 4.7 cm y−1 in the Puscasi Reservoir at the catchment outlet, resulting in an associated sediment delivery ratio of 0.28. The initial area of the Puscasi Reservoir at normal retention level has decreased by 32% and the water storage capacity has decreased by 39%. Consequently, land degradation remains a serious problem in the study area and effective soil conservation is urgently needed.

Erosion assessment in the desertification site of Gilbues, Brazil

2020 ◽  
Author(s):  
José Carlos de Araújo ◽  
Antonio Álisson Simplício ◽  
Francisco Jairo Pereira ◽  
Carlos Alexandre Gomes Costa
Keyword(s):  
Monitoring Program ◽  
Hydroelectric Power Plant ◽  
High Rate ◽  
Soil Restoration ◽  
Delivery Ratio ◽  
Hydroelectric Power ◽  
Rill Erosion ◽  
Vegetative Cover ◽  
Sediment Delivery ◽  
Check Dams

&lt;p&gt;The Gilbu&amp;#233;s Desertification Site (GDS) is an 8,000-km&amp;#178; area located in the Northeast of Brazil. It comprises large continuous areas with deep (up to 30 m), wide (up to 50 m), and long (up to 6 km) gullies, as well as severe inter-rill erosion. Inside the GDS there is an experimental site, in which almost 100 check dams were constructed a decade ago to assess their feasibility as a soil-restoration initiative. For two years (2018 and 2019) we have monitored a 15-ha watershed that contains 52 check dams so as to estimate the main erosion-related parameters as well as to assess the effectiveness of the check dams. The monitoring program consisted of (i) a climate station; (ii) four hillslopes with pins every m&amp;#178;, measured monthly to quantify gross erosion; (iii) five flights with an accurate unmanned aerial vehicle (UAV) to identify the siltation of the check dams and to parameterize the rainfall-runoff behavior; (iv) 92 soil samples in the hillslopes and inside the check dams; and (v) four infiltration experiments. The results show that (i) the gross erosion is 8 mm.yr&lt;sup&gt;-1&lt;/sup&gt;, or 10&amp;#178; Mg.ha&lt;sup&gt;-1&lt;/sup&gt;.yr&lt;sup&gt;-1&lt;/sup&gt;, a value ten times higher than the region average; (ii) based on the silting of the check dams, the sediment yield averaged 85 Mg.ha&lt;sup&gt;-1&lt;/sup&gt;.yr&lt;sup&gt;-1&lt;/sup&gt;, 20 times higher than the regional mean value, which is partially explained by the small size of the watersheds (10&amp;#178;-10&amp;#179; m&amp;#178;); (iii) the Wischmeier vegetation C factor is 0.9, showing high degree of vegetative-cover degradation; and (iv) the sediment delivery ratio was 0.8, which could be satisfactorily represented by the Maner equation. These results show that, although the GDS corresponds to only 10% of the Boa Esperan&amp;#231;a (5,000 hm&amp;#179;) hydroelectric power plant basin, it may cause 60% of the reservoir silting. The GDS soil has also shown specific properties: 71% of the soil mass has a diameter of ~ 0.1 mm; there is a high rate of open macro-pores when the soil is dry (they close shortly after a moderate rainfall event ~ 40 mm); and it is prone to form gravel-like particles that silt in the reservoir delta (despite its fine diameter). Last, we observed that the check dams &amp;#8211; as they were built &amp;#8211; are not a sustainable solution: after a decade, nearly 10% are spilling due to the high siltation rates, causing dam-wall erosion and instability; and three dams have presented piping, with discharges (0.2 &amp;#8211; 0.7 L.s&lt;sup&gt;-1&lt;/sup&gt;) one thousand times higher than the expected percolation flow through the dams.&lt;/p&gt;

scholarly journals Catchment Sediment Dynamics and the Role of Deep-Seated Landslide-Dams; Waipaoa Catchment, Raukumara Peninsula, New Zealand

2021 ◽  
Author(s):  
◽  
Richard James Taylor
Keyword(s):  
Sediment Transport ◽  
Large Scale ◽  
Gully Erosion ◽  
Sediment Dynamics ◽  
Storm Events ◽  
14C Dating ◽  
Sediment Delivery ◽  
Ground Shaking ◽  
Landslide Dams ◽  
The Impact

<p>Sediment volumes retained by landslide-dams of the Waipaoa are small at 1.85x10⁶m³ compared to the 24.5km³ (Marden et al., 2008b) of sediment eroded in the landscape since the last glacial maximum. Landslide-dams do however represent a major perturbation to sediment transport, although due to their mainly short life span this disruption is discontinuous representing a pulsing in the transport network. The objective of this study is to investigate the sedimentary dynamics of the Waipaoa catchment by providing insights into the role that deep-seated landslides play and asks the questions: What is the impact on sediment transport imposed by the landslide-dams of the Waipaoa catchment? and; What do the sediments impounded in landslide-dammed lakes tell us about catchment sediment dynamics through time? The Waipaoa River on the East Cape of New Zealand‘s North Island delivers volumes of sediment to the coast which are considered high by global standards. Catchment erosion is controlled by soft marine sediments, combined with a history of tectonic fracturing and frequent intense rain storms. Erosion events are driven by intense cyclonic systems rain storms which deliver ≥200mm/24hr rainfall and induce catchment wide gully erosion as well as shallow surficial landslides. Under current land covers gully erosion provides the dominant source of sediments, with high degrees of slope channel coupling and steep gradient river profiles providing for efficient delivery to the coast. Offshore in the Poverty Bay, sediments delivered by the Waipaoa River show considerable variability over a range of temporal scales. Valley slopes within the Waipaoa catchment are also susceptible to large deep-seated landslide failures, with movement depths greater than 5 metres often on internal structural failure planes. These large slope movements can be produced by both extreme storm events (≥300mm/24hr) which occur on a return periods of 1 in 5 years and seismic ground shaking of 1 in 1000-2000 years. Where these large events block channels and are able to persist for long periods, sediments accumulated upstream to provide a unique record of the catchments sedimentary history. There have been some 1100 historic large scale features which have been identified within the Waipaoa region, with this study selecting seven that have shown evidence of channel blockage. The project aims to provide insights into the age of a sample of deep-seated landslides that have dammed channels to determine how long landslide-dams survive in the landscape and quantify the volumes of sediment they have trapped. Further, the project aims to determine what the spatial and temporal distribution of these blockages has meant to sediment delivery and whether there have been changes in sediment dynamics in their upper catchments over time. The project uses the detailed mapping of the trapped body of sediments, GIS modelling of the palaeo and present landscapes and age control determinations provided by tephra and 14C dating to provide both volumes and rates of sediment delivery.</p>

Ephemeral Gully Erosion Advancements within the AnnAGNPS Watershed Simulation Model

2020 ◽  
Author(s):  
Ronald Bingner ◽  
Robert Wells ◽  
Henrique Momm
Keyword(s):  
Conservation Management ◽  
Gully Erosion ◽  
Conservation Practices ◽  
Rill Erosion ◽  
Management Planning ◽  
Channel Erosion ◽  
Ephemeral Gully ◽  
Ephemeral Gullies ◽  
The Impact ◽  
The U.S

&lt;p&gt;Concentrated runoff increases erosion and moves fine sediment and associated agrichemicals from upland areas to stream channels. Ephemeral gully erosion on croplands in the U.S. may contribute more of the sediment delivered to the edge of the field then from sheet and rill erosion. Typically, conservation practices developed for sheet and rill erosion are also expected to treat ephemeral gully erosion, but science and technology are needed to account for the separate benefits and effects of practices on each of the various sediment sources.&lt;/p&gt;&lt;p&gt;Watershed modeling technology has been widely developed to aid in evaluating conservation practices implemented as part of a management plan, but typically lacks the capability to identify how a source, such as sheet and rill erosion, ephemeral gully erosion, or channel erosion, is specifically controlled by a practice or integrated practices. The U.S. Department of Agriculture&amp;#8217;s Annualized Agricultural Non-Point Source pollutant loading model, AnnAGNPS, has been developed to determine the effects of conservation management plans on erosion and provide sediment tracking from all sources within the watershed, including sheet and rill, ephemeral gully, and channel erosion.&amp;#160;&lt;/p&gt;&lt;p&gt;This study describes the ephemeral gully erosion capabilities within the AnnAGNPS model and discusses research needs to further improve these components for integrated conservation management planning. &amp;#160;Conservation management planning by agencies within the U.S. and by international organizations requires a systematic approach when determining the extent of ephemeral gully erosion impacts on a field, watershed, or national basis, and/or to predict recurring or new locations of ephemeral gullies prior to their development.&amp;#160; This technology provides the capability to separate the impact of ephemeral gullies on erosion from other sources and then evaluate the impact of targeted practices to control erosion at the source and subsequent downstream resources.&lt;/p&gt;

KAJIAN EROSI LAHAN DI KAWASAN AIR STRIP RUNWAY 2600 BANDARA DEPATI AMIR (PGK) BERDASARKAN TATA GUNA LAHAN MASTERPLAN ULTIMATE

2019 ◽  
Vol 7 (2) ◽  
pp. 100-111
Author(s):  
Miskar Maini ◽  
Junita Eka Susanti
Keyword(s):  
Sediment Yield ◽  
Soil Loss ◽  
Universal Soil Loss Equation ◽  
Delivery Ratio ◽  
Sediment Delivery Ratio ◽  
Sediment Delivery ◽  
Soil Loss Equation

Standar permintaan engineering pesawat agar desain bangunan infrastruktur di area Air Strip Runway 2600 yang ada dapat mempunyai fungsi lain. Sedangkan kondisi lain sangat menentukan keselamatan karena lahan di sekitar Air Strip Runway 2600 Bandara Depati Amir (PGK) jika tidak ditutupi vegetasi seperti rumput, kondisi lain lahan yang belum ditutupi vegetasi di sekitar Air Strip Runway 2600 berpotensi akan mengalami erosi lahan, kemudian hasil erosi lahan ini akan terbawa oleh aliran air sehingga akan masuk ke saluran drainase yang akan menyebabkan sedimentasi pada saluran drainase tersebut, akhirnya akan berkurang efektifitas kinerja saluran drainase tersebut. Metode yang digunakan untuk memprediksi laju rata-rata erosi di area Air Strip Runway 2600 dengan memperhitungkan faktor erosivitas hujan, erodibilitas tanah, kemiringan lereng atau panjang lereng, pengelolaan tanaman dan konservasi tanah, yang masing masing tata guna lahan tersebut mengacu pada Masterplan Ultimate Bandara Depati Amir (PGK). Perhitungan dilakukan menggunakan persamaan USLE (Universal Soil Loss Equation) yang dikembangkan oleh Wischmeier dan Smith (1965, 1978), kemudian Sediment Delivery Ratio (SDR) dan Sediment Yield.Hasil penelitian ini, prediksi laju erosi permukaan pada area Air Strip Runway 2600 Bandara Depati Amir (PGK) tahun pertama yang mencapai 5,60 mm/tahun atau 100,76 Ton/Ha/tahun, laju erosi tahun kedua mencapai 3,38 mm/tahun atau 60,84 Ton/Ha/tahun dapat diklasifikasikan ke dalam kelas bahaya erosi sedang (kelas III) dan nilai SDR adalah sebesar 56,3%, nilai sediment yield (SR) pada tahun pertama sebesar 5.887,59 Ton/Tahun, pada tahun kedua ketika rumput pada area Air Strip telah tumbuh dengan sempurna terjadi penurunan hasil sediment yield yaitu nilai SR sebesar 3.554,85 Ton/Tahun.

scholarly journals Factors influencing the sediment delivery ratio of the Three Gorges Reservoir

2018 ◽  
Vol 40 ◽  
pp. 03019
Author(s):  
Dayu Wang ◽  
Chunhong Hu ◽  
Chunming Fang ◽  
Jianzhao Guan ◽  
Lei Zhang
Keyword(s):  
Sensitivity Analysis ◽  
Three Gorges Reservoir ◽  
Delivery Ratio ◽  
Three Gorges ◽  
Sediment Delivery Ratio ◽  
Sediment Delivery ◽  
Shape Coefficient ◽  
The Three Gorges Reservoir ◽  
The Three Gorges ◽  
Dam Site

In recent years, the sediment delivery ratio (SDR) of the Three Gorges reservoir (TGR) has noticeably decreased as a result of the increase in water levels at the dam site and the decrease in inflow of fine particles, thereby resulting in increased reservoir siltation. Therefore, it is vital to research the factors that influence the SDR of the TGR. Factors that could have impact on the SDR were studied using TGR monitoring data. The study indicated that the water level at the dam site and inflow and outflow rates could have contributed to the change in the SDR. A sensitivity analysis of the influencing factors was then carried out using a mathematical model to simulate numerous sediment movement scenarios in the TGR. By changing the input conditions of the model, sufficient results were obtained to enable a sensitivity analysis of each factor. The results showed the flood retention time (FRT)—the ratio of reservoir capacity to average outflow discharge—was the principal factor influencing the SDR. The other factors (inflow sediment concentration, inflow sediment coefficient, inflow sediment gradations, and the shape coefficient of the inflow flood shape coefficient), also had an influence on the SDR. However, under different levels of FRT, their degrees of influence on the SDR were not the same..

scholarly journals Solute transport dynamics in small, shallow groundwater-dominated agricultural catchments: insights from a high-frequency, multisolute 10 yr-long monitoring study

2013 ◽  
Vol 17 (4) ◽  
pp. 1379-1391 ◽  
Author(s):  
A. H. Aubert ◽  
C. Gascuel-Odoux ◽  
G. Gruau ◽  
N. Akkal ◽  
M. Faucheux ◽  
...  
Keyword(s):  
High Frequency ◽  
Inorganic Carbon ◽  
Shallow Groundwater ◽  
Data Series ◽  
Wet Season ◽  
Transport Dynamics ◽  
Agricultural Catchments ◽  
Organic And Inorganic Carbon ◽  
The Impact

Abstract. High-frequency, long-term and multisolute measurements are required to assess the impact of human pressures on water quality due to (i) the high temporal and spatial variability of climate and human activity and (ii) the fact that chemical solutes combine short- and long-term dynamics. Such data series are scarce. This study, based on an original and unpublished time series from the Kervidy-Naizin headwater catchment (Brittany, France), aims to determine solute transfer processes and dynamics that characterise this strongly human-impacted catchment. The Kervidy-Naizin catchment is a temperate, intensive agricultural catchment, hydrologically controlled by shallow groundwater. Over 10 yr, five solutes (nitrate, sulphate, chloride, and dissolved organic and inorganic carbon) were monitored daily at the catchment outlet and roughly every four months in the shallow groundwater. The concentrations of all five solutes showed seasonal variations but the patterns of the variations differed from one solute to another. Nitrate and chloride exhibit rather smooth variations. In contrast, sulphate as well as organic and inorganic carbon is dominated by flood flushes. The observed nitrate and chloride patterns are typical of an intensive agricultural catchment hydrologically controlled by shallow groundwater. Nitrate and chloride originating mainly from organic fertilisers accumulated over several years in the shallow groundwater. They are seasonally exported when upland groundwater connects with the stream during the wet season. Conversely, sulphate as well as organic and inorganic carbon patterns are not specific to agricultural catchments. These solutes do not come from fertilisers and do not accumulate in soil or shallow groundwater; instead, they are biogeochemically produced in the catchment. The results allowed development of a generic classification system based on the specific temporal patterns and source locations of each solute. It also considers the stocking period and the dominant process that limits transport to the stream, i.e. the connectivity of the stocking compartment. This mechanistic classification can be applied to any chemical solute to help assess its origin, storage or production location and transfer mechanism in similar catchments.

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