Assessing the contribution of natural and anthropogenic processes on sediment dynamics in the Rio Santa (Peru) through sediment fingerprinting

2021 ◽  
Author(s):  
Jessica Kitch ◽  
Caroline Clason ◽  
Sally Rangecroft ◽  
Sergio Morera ◽  
Will Blake
Keyword(s):  
Resource Management ◽  
Soil Erosion ◽  
Water Resource Management ◽  
Agricultural Land ◽  
Sediment Dynamics ◽  
Sediment Fingerprinting ◽  
Sediment Sources ◽  
Transport Pathway ◽  
Distributed Approach ◽  
The Impact

<p>The combination of a changing climate and growing population poses a contemporary challenge for the water-food-energy security nexus in mountain regions, especially in glacier-fed catchments such as the Rio Santa in the Peruvian Andes. Soil erosion due to both natural processes and anthropogenic activities can exacerbate this challenge, with increased levels of sediment in river systems endangering crucial river functions, such as crop irrigation, drinking water, and hydroelectricity. Furthermore, sediment can act as a transport pathway for contaminants, in addition to being a source of contamination itself. Previous studies have suggested that soil erosion related to human activity vastly exceeds the rate of natural soil production in many Andean catchments, where research to date has primarily focused on larger eastern catchments. Smaller western catchments, however, are important for many major Andean cities reliant upon upstream water supplies. It is thus, important to identify sediment sources and better understand sediment dynamics to manage the threats to water supply.</p><p>Sediment fingerprinting approaches are one technique that can contribute to improved understanding of sediment sources and dynamics and the impact of soil erosion in a catchment, and thus contribute to water resource management at the catchment level. Taking a distributed approach along the Rio Santa, this study aims to improve understanding of natural and anthropogenic contributions to sediment production in this Andean system. Key sediment sources explored are glacial sediment potentially enhanced by retreat, agricultural land, forestry operations, land under natural vegetation, and mining. The distributed approach permits quantification of their dynamics throughout the catchment. All source and mixture samples were analysed using Wavelength Dispersive X-ray Fluorescence (WD XRF) to develop geochemical fingerprints and the MixSIAR mixing model was used to apportion sediment sources. While sediment sampling presents a number of challenges when working in remote, mountainous regions such as the Rio Santa catchment, sediment fingerprinting has the potential to help reduce environmental degradation when used to guide local resource management decisions.</p>

Evaluating the effects of tracer selection, source dominance and source number on the accuracy and sensitivity of source apportionment using sediment fingerprinting. 

2021 ◽  
Author(s):  
Simon Vale ◽  
Andrew Swales ◽  
Hugh Smith ◽  
Greg Olsen ◽  
Ben Woodward
Keyword(s):  
Land Cover ◽  
Source Apportionment ◽  
Model Performance ◽  
Common Source ◽  
Native Forest ◽  
Test Model ◽  
Sediment Fingerprinting ◽  
Sediment Sources ◽  
Dominant Source ◽  
The Impact

<p>Sediment fingerprinting is a technique for determining the proportional contributions of sediment from erosion sources delivered to downstream locations. It involves selecting tracers that discriminate sediment sources and determining contributions from those sources using tracers.  These tracers can include geochemical, fallout radionuclides, magnetic properties, and compound specific stable isotope (CSSI) values of plant-derived biotracers that label of soils and sediment.  A range of tracer applications and developments in source un-mixing have been demonstrated in the literature and, while the basis for discriminating sediment sources is reasonably well understood, research has drawn increasing attention to limitations and uncertainties associated with source apportionment. Numerical mixtures provide a way to test model performance using idealized mixtures with known source proportions. Although this approach has been applied previously, it has not been used to test and compare model performance across a range of tracer types with varied source contribution dominance and number of sources.</p><p>We used numerical mixtures to examine the ability of two different tracer sets (geochemical and CSSI), each with two tracer selections, to discriminate sources using a common source dataset. Sources were sampled according to erosion process and land cover in the Aroaro catchment (22 km<sup>2</sup>), New Zealand.  Here we sampled top-soils and sub-soils from pasture (n = 12 sites), harvested pine (12), kanuka scrub (7) and native forest (4) locations. Composite soil samples were collected at 0-2 and 40-50 cm depth increments to represent surface and shallow landslide (subsoil) erosion sources. Stream sediment (11) samples were also collected for initial unmixing.  Here, we focus on using numerical mixtures with geochemical and CSSI tracers for an increasing number of sources (3 to 6) where each individual and pairwise combination of sources were systematically set as the dominant source.  Since mixing models for CSSI tracers produce source contributions based on isotopic proportions (Isotopic%) instead of soil contributions (Soil%), CSSI numerical mixtures were created for Isotopic% and Soil% to assess the impact this correction factor may have on model performance.  In total, over 400 model scenarios were tested.</p><p>Numerical mixture testing indicated that the dominant source can have a significant impact on model performance.  If the dominant source is well discriminated, then the model performs well but accuracy declines significantly as discrimination of the dominant source reduces. This occurs more frequently with an increasing number of sources. The geochemical dataset performed well for erosion-based sources while both tracer sets produced larger apportionment errors for land cover sources. CSSI model performance was generally poorer for Soil% than Isotopic%, indicating high sensitivity to the percent soil organic carbon in each source, especially when there are large differences in organic matter between sources.</p><p> </p>

scholarly journals Analysis of Farmers’ Perception on the Impact of Land Degradation Hazard on Agricultural Land Productivity in Jeldu District in West Shewa Zone, Oromia, Ethiopia

2018 ◽  
Vol 8 (2) ◽  
pp. 20
Author(s):  
Tesfaye Samuel Saguye
Keyword(s):  
Soil Erosion ◽  
Land Management ◽  
Land Degradation ◽  
Management Practices ◽  
Local Community ◽  
Agricultural Land ◽  
Land Productivity ◽  
Community Knowledge ◽  
Process Indicators ◽  
The Impact

Land degradation is increasing in severity and extent in many parts of the world. Success in arresting land degradation entails an improved understanding of its causes, process, indicators and impacts. Various scientific methodologies have been employed to assess land degradation globally. However, the use of local community knowledge in elucidating the causes, process, indicators and effects of land degradation has seen little application by scientists and policy makers. Land degradation may be a physical process, but its underlying causes are firmly rooted in the socio-economic, political and cultural environment in which land users operate. Analyzing the root causes and effects of land degradation from local community knowledge, perception and adapting strategies perspective will provide information that is essential for designing and promoting sustainable land management practices. The main objective of this study was to analyze the perceptions of farmers’ on the impact of land degradation hazard on agricultural land productivity decline associated with soil erosion and fertility loss. The study used a multistage sampling procedure to select sample respondent households. The sample size of the study was 120 household heads and 226 farm plots managed by these farmers. The primary data of the study were collected by using semi-structured Interview, focus group discussions and field observation. Both descriptive statistics and econometric techniques were used for data analysis. Descriptive results show that 57percent of the respondents were perceived the severity and its consequence on agricultural land productivity. The following indicators of soil erosion and fertility loss were generally perceived and observed by farmers’ in the study area: gullies formations, soil accumulation around clumps of vegetation, soil deposits on gentle slopes, exposed roots, muddy water, sedimentation in streams and rivers, change in vegetation species, increased runoff, and reduced rooting depth. The direct human activities which were perceived to be causing land degradation in the study area include: deforestation and clearing of vegetation, overgrazing, steep slope cultivation and continuous cropping. The farmers’ possibility of perceiving the impact of land degradation hazard on agricultural land productivity was primarily determined by institutional, psychological, demographic and by bio-physical factors. Farmers who perceive their land as deteriorating and producing less than desired, tend to adopt improved land management practices. On the other hand, farmers who perceive their land to be fertile tend to have low adoption of conservation practices. In order to overcome this land degradation and its consequent effects, the study recommended a need for the government to enforce effective policies to control and prevent land degradation and these policies should be community inclusive /participatory founded up on indigenous and age-honored knowledge and tradition of farmers' natural resource management as well as introduced scientific practices.

Agricultural land use and N losses to water: the case study of a fluvial park in Northern Italy

2003 ◽  
Vol 47 (7-8) ◽  
pp. 275-282 ◽  
Author(s):  
F. Morari ◽  
E. Lugato ◽  
M. Borin
Keyword(s):  
Water Quality ◽  
Best Management Practices ◽  
Water Resource Management ◽  
Management Practices ◽  
Agricultural Land ◽  
Subsurface Water ◽  
Agricultural Systems ◽  
N Losses ◽  
Positive Effects ◽  
The Impact

An integrated water resource management programme has been under way since 1999 to reduce agricultural water pollution in the River Mincio fluvial park. The experimental part of the programme consisted of: a) a monitoring phase to evaluate the impact of conventional and environmentally sound techniques (Best Management Practices, BMPs) on water quality; this was done on four representative landscape units, where twelve fields were instrumented to monitor the soil, surface and subsurface water quality; b) a modelling phase to extend the results obtained at field scale to the whole territory of the Mincio watershed. For this purpose a GIS developed in the Arc/Info environment was integrated into the CropSyst model. The model had previously been calibrated to test its ability to describe the complexity of the agricultural systems. The first results showed a variable efficiency of the BMPs depending on the interaction between management and pedo-climatic conditions. In general though, the BMPs had positive effects in improving the surface and subsurface water quality. The CropSyst model was able to describe the agricultural systems monitored and its linking with the GIS represented a valuable tool for identifying the vulnerable areas within the watershed.

scholarly journals Dynamics of Water Quality: Impact Assessment Process for Water Resource Management

Processes ◽  
2019 ◽  
Vol 7 (2) ◽  
pp. 102 ◽  
Author(s):  
Ejaz-ul-Hassan Bhatti ◽  
Mudasser Muneer Khan ◽  
Syyed Adnan Raheel Shah ◽  
Syed Safdar Raza ◽  
Muhammad Shoaib ◽  
...  
Keyword(s):  
Water Quality ◽  
Resource Management ◽  
Water Resource ◽  
Water Resource Management ◽  
Assessment Process ◽  
Irrigation Canal ◽  
Quality Of Water ◽  
Irrigation Purpose ◽  
The Impact

Surface water is an important source of water supply for irrigation purpose and in urban areas, sewage water is being disposed of in nearby canals without treatment. A study was conducted to investigate the dynamics of water quality of irrigation canal as a result of this practice. The study ascertained the impact of different salinity parameters, indices and approaches to examine the hazardous effects on quality of canal water. The study analyses the samples collected for various parameters like pH, TDS, EC, Na, Cl, Ca, Mg, K, CO3, HCO3 etc. It helped to decide the restriction on use of water based on FAO-UN guidelines. Investigations were focused on assessment of contaminants affecting the quality of water and having hazardous effects on different stages of irrigation water usage. Wilcox diagram and Doneen’s approach-based analysis helped to identify the class and quality of water. This study shall help to analyze the quality of water and provide support to the decision makers for better water resource management and policy development for irrigation purpose i.e. treatment and distribution of water resource.

scholarly journals The application of a drought reconstruction in water resource management

2015 ◽  
Vol 47 (3) ◽  
pp. 646-659 ◽  
Author(s):  
A. T. Lennard ◽  
N. Macdonald ◽  
S. Clark ◽  
J. M. Hooke
Keyword(s):  
Resource Management ◽  
Water Resource ◽  
Water Resource Management ◽  
Climate Data ◽  
Standardised Precipitation Index ◽  
Current Water ◽  
Water Companies ◽  
Resource Modelling ◽  
Resource Sector ◽  
The Impact

This study uses extended (1880s–2012) rainfall series to examine the implications of historical droughts on water supply yield calculations used in water resource management and drought planning across the English Midlands and Central Wales. UK guidance to water companies is to use climate data from the 1920s to present where possible in modelling to inform water resource management and drought plans; but this period excludes several significant droughts of the late 19th century. This study uses the standardised precipitation index and hydrological modelling (HYSIM and AQUATOR) to investigate the implications of pre-1920s droughts on water resource management. Although drought characterisation identifies two significant droughts in the pre-1920 period, the impact of these events on reservoir storage is less severe than droughts identified in the post-1920 period, indicating that the use of long climate series in water resource modelling is a valuable tool in assessing the robustness of current water resource modelling used in the water resource sector.

scholarly journals Water Resource Management: Moving from Single Risk-Based Management to Resilience to Multiple Stressors

2021 ◽  
Vol 13 (15) ◽  
pp. 8609
Author(s):  
Sarah Bunney ◽  
Elizabeth Lawson ◽  
Sarah Cotterill ◽  
David Butler
Keyword(s):  
Resource Management ◽  
Water Resource ◽  
Water Demand ◽  
Water Resource Management ◽  
Large Scale ◽  
Multiple Stressors ◽  
Meteorological Data ◽  
Average Rainfall ◽  
The Uk ◽  
The Impact

Water resource management in the UK is multifaceted, with a complexity of issues arising from acute and chronic stressors. Below average rainfall in spring 2020 coincided with large-scale changes to domestic water consumption patterns, arising from the first UK-wide COVID-19 lockdown, resulting in increased pressure on nationwide resources. A sector wide survey, semi-structured interviews with sector executives, meteorological data, water resource management plans and market information were used to evaluate the impact of acute and chronic threats on water demand in the UK, and how resilience to both can be increased. The COVID-19 pandemic was a particularly acute threat: water demand increased across the country, it was unpredictable and hard to forecast, and compounding this, below average rainfall resulted in some areas having to tanker in water to ‘top up’ the network. This occurred in regions of the UK that are ‘water stressed’ as well as those that are not. We therefore propose a need to look beyond ‘design droughts’ and ‘dry weather average demand’ to characterise the management and resilience of future water resources. As a sector, we can learn from this acute threat and administer a more integrated approach, combining action on the social value of water, the implementation of water trading and the development of nationwide multi-sectoral resilience plans to better respond to short and long-term disruptors.

The Combined Effect of Vegetation and Soil Erosion in the Water Resource Management

2010 ◽  
Vol 24 (13) ◽  
pp. 3701-3714 ◽  
Author(s):  
Mohsin Jamil Butt ◽  
◽  
Ahmad Waqas ◽  
Rashed Mahmood
Keyword(s):  
Resource Management ◽  
Soil Erosion ◽  
Water Resource ◽  
Water Resource Management ◽  
Combined Effect
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