Case Study Of Catchment Research Articles

Prioritizing dam removal and stream restoration using critical habitat patch threshold for brown trout (Salmo trutta L.): a catchment case study from Sweden

ABSTRACTCatchments form an important terrestrial-aquatic habitat complex for biodiversity conservation and human well-being. Riparian and stream components are debated about how much habitat need to be maintained or restored in rivers subject to habitat degradation and fragmentation. Using brown trout as a focal species we tested the hypothesis that presence of suitable habitat in lotic stream sections can be predicted using habitat modelling. We modelled brown trout habitat at the catchment scale in terms of quality, size, juxtaposition of stream segments using digital elevation data, and presence of dams. The habitat models were validated against presence-absence data for local brown trout populations. A self-reproducing brown trout population was defined as having three year-classes. We identified the required minimum length (270 m) of a lotic stream section hosting a local brown trout population, corresponding to 3500 m2. Adjacent areas of lotic stream habitat between dams had a significant positive effect on brown trout presence. The abundance of brown trout was significantly positively correlated to habitat quality, and negatively to hydropower water regulation. Critical habitat loss thresholds can be used for gap analysis regarding selection of dams to be removed and where restoration measures will be most effective in a catchment.

Modelling the impact of rural land use scenarios on water management: a FREEWAT approach to the Bakumivka catchment case study, Ukraine

The Bakumivka River’s catchment, Ukraine serves as a case study to the application of FREEWAT to the ground and surface water management. The main objective of the study is to find out the optimal spatial distribution of the water supplied to the farms by modifying the land cover pattern of the catchment. An integrated numerical model was developed to provide quantitative estimates of the water budget components. The model includes four model layers, representing the main hydrostratigraphic units, different types of boundary conditions assigned along the area’s boundaries, major components of the water balance introduced through source and sink layers. It was implemented through the FREEWAT software. Three water management scenarios were developed in order to compare different spatial patterns of land cover and distribution of water within the Bakumivka River’s basin. The scenarios represent continuum from market oriented pattern to environmentally sounding pattern of land cover. The objective of the modeling exercise is to obtain mass balances and maps representing three scenarios of water management. Each map shows distribution of the areas where the water balance is optimal, insufficient (dry) or excessive (wet) for vegetation (land cover) of particular type.The simulation shows that changing spatial land cover pattern is an effective measure to reduce water supply to the farms, however it does not prevent water logging in the areas adjacent to the flood plains and drying on summer stress periods in lands of sandyloam soils. Irrigation should be excluded in the areas with sandy and sandyloam soils. The flood plain with peat bogs despite the high water head in spring and late summer stress periods should be irrigated to prevent peat fires. The intrusion of eco-corridors to the land cover pattern in the catchment is positive from ecological perspective, but could prevent drainage causing water logging in the arable lands.

A hydraulic invariance‐based methodology for the implementation of storm‐water release restrictions in urban land use master plans

AbstractA hydraulic invariance (HI)‐based methodology was developed as a tool to support implementation of storm flow control measures into land use master plans (LUMPs) for urban catchments. The methodology is based on the use of simple hydrologic analysis to compare predevelopment and postdevelopment catchment flow release scenarios. Differently from previous literature examples, for which the parcel scale is usually considered for the analysis, HI was pursued assuming the LUMP areas of transformation as the basic units for assigning storm water control measures in the form of flow release restrictions. The methodology was applied to a case study catchment in the southern part of the City of Catania (Italy), for which the LUMP re‐design has been recently proposed. Simulations were run based on the use of the EPA‐Storm Water Management Model and allowed deriving flow release restrictions in order to achieve HI at the subcatchment level for design events of different return period.

Use of a scenario-neutral approach to identify the key hydro-meteorological attributes that impact runoff from a natural catchment

Scenario-neutral approaches are being used increasingly for assessing the potential impact of climate change on water resource systems, as these approaches allow the performance of these systems to be evaluated independently of climate change projections. However, practical implementations of these approaches are still scarce, with a key limitation being the difficulty of generating a range of plausible future time series of hydro-meteorological data. In this study we apply a recently developed inverse stochastic generation approach to support the scenario-neutral analysis, and thus identify the key hydro-meteorological variables to which the system is most sensitive. The stochastic generator simulates synthetic hydro-meteorological time series that represent plausible future changes in (1) the average, extremes and seasonal patterns of rainfall; and (2) the average values of temperature (Ta), relative humidity (RH) and wind speed (uz) as variables that drive PET. These hydro-meteorological time series are then fed through a conceptual rainfall-runoff model to simulate the potential changes in runoff as a function of changes in the hydro-meteorological variables, and runoff sensitivity is assessed with both correlation and Sobol’ sensitivity analyses. The method was applied to a case study catchment in South Australia, and the results showed that the most important hydro-meteorological attributes for runoff were winter rainfall followed by the annual average rainfall, while the PET-related meteorological variables had comparatively little impact. The high importance of winter rainfall can be related to the winter-dominated nature of both the rainfall and runoff regimes in this catchment. The approach illustrated in this study can greatly enhance our understanding of the key hydro-meteorological attributes and processes that are likely to drive catchment runoff under a changing climate, thus enabling the design of tailored climate impact assessments to specific water resource systems.

Aquatic eutrophication indicators in LCA: Methodological challenges illustrated using a case study in New Zealand

ObjectiveThe objective of this work was to determine the effects and implications of generic and site-specific aquatic eutrophication potential indicators in the Life Cycle Assessment (LCA) of livestock farm systems using a New Zealand (NZ) lake catchment case study. MethodAverage dairy and sheep & beef farm systems in the Lake Taupo catchment were studied. Emissions of nitrogen (N) and phosphorus (P) to waterways, and ammonia and nitrogen oxides to air from these farms were calculated using the site-specific OVERSEER® nutrient budget model. These emissions data were then used to calculate the increase in nutrients in water bodies and aquatic Eutrophication indicators with a range of Life Cycle Impact Assessment (LCIA) methods. ResultsEutrophication indicator results varied considerably depending on the environmental mechanisms modelled by the LCIA method for the fate of N and P, accentuated by different choices for the inventory modelling. Using default emission factors instead of site-specific ones overestimated eutrophication impact results. The most recent methods are not only spatially-explicit and applicable beyond Europe, but they also account for more environmental mechanisms for the fate of the nutrients, giving relatively lower calculated impact results. However, the appropriate scale and spatial resolution is still a crucial question to address for these methods since they greatly affect results. Regarding eutrophication damage assessment, when the actual background nutrient concentration is very low, the end-point assessment method for freshwater eutrophication is not applicable. In this case, LCA fails to account for a high standard of water quality that is in a near-pristine state, but deteriorating. ConclusionsThe inventory of nutrient flows at a farm scale and fate factors modelled at a catchment scale should be site-specific. Freshwater eutrophication indicators should be based on a site-specific (and globally-valid) LCIA model rather than a generic one. Currently-accepted freshwater eutrophication indicators focus only on P, thus capturing only part of the problem for freshwater bodies that are co-limited by N and P (in terms of algal growth) such as Lake Taupo in NZ. Lake Taupo water quality concerns and regulations are not focused on P, but solely on N due to increasing N levels over time. Conclusions from this study are valid beyond NZ and beyond agricultural systems. Future work needs to investigate coupling N and P fate modelling based on the most recent globally-valid and spatially-explicit LCIA methods.

Remote sensing upscaling of interception loss from isolated oaks: Sardon catchment case study, Spain

Tree interception loss from two Mediterranean oak species, Quercus ilex (Q.i.) and Quercus pyrenaica (Q.p.), was estimated during 2-year period (1 October 2011 to 30 September 2013) in sparsely vegetated Sardon catchment (∼80km2, Spain) by: i) rainfall, throughfall and stemflow measurements; ii) Gash model temporal extrapolation; and iii) remote-sensing spatial upscaling. The annual, measured tree interception losses (Im) of Q.i. and Q.p. in the first year were 51% and 16% of P (335mm) and in the second, 46% and 10% of P (672mm), respectively. The revised Gash analytical model of rainfall interception loss, extrapolated well the Im temporal variability of Q.i. and Q.p., provided the throughfall-based, and not Pennman-Monteith-based, average wet canopy evaporation rates were used. Finally, a novel method of spatial upscaling of a tree-based interception loss into plot- and catchment-scale, using per-species, reference tree interception loss and object-attributes derived from satellite imagery, was proposed. The interception losses from Q.i. and Q.p. were upscaled first into two homogeneous plots (1-ha each and both with ∼20% canopy cover), one with Q.i. and the other with Q.p. oaks and then into the entire Sardon catchment with ∼7% canopy cover. The obtained annual-mean, plot interception losses were 9.5% of P in evergreen Q.i. and 2.5% of P in deciduous Q.p. plot. The annual-mean catchment interception loss was 1.4% of P. The proposed upscaling method is expected to improve catchment water balances, replacing common arbitrary or literature based tree interception loss estimates.

Evaluating multifunctionality and adaptive capacity of mountain forest management alternatives under climate change in the Eastern Alps

Future provisioning of ecosystem services (ES) from mountain forests is uncertain due to potential impacts of climate change. For a case study catchment in the Eastern Alps in Austria we analysed how management and climate change may affect the provisioning of four ES (timber production, carbon sequestration, biodiversity and bird habitat quality, and protection against gravitational hazards). We used the PICUS forest ecosystem model to project seven management alternatives that differed with regard to cutting pattern size (SLIT, PATCH, STRIP) and two harvesting intensity levels (in terms of return interval) under historic climate and five transient climate change scenarios over 100 years. In addition no management and sanitary management were simulated. In total twelve indicators were linked to model output to quantify ES provisioning. Results under historic climate showed increased volume and carbon stocks in low-intensity management, while high-intensity management decreased stocks. Bird habitat quality was maintained only by low-intensity management using SLIT and PATCH cuts. In particular rockfall protection decreased strongly under the STRIP cut scenario. Improved tree growth in warming scenarios was counterbalanced by increasing damage from bark beetle disturbances. Canopy openings and increased deadwood supply from disturbances partly fostered bird habitat quality in no-management alternatives. Overall none of the management alternatives performed best for all ES. PATCH and SLIT regimes at (currently practiced) low intensity appeared as compromise to achieve multifunctionality at small scale. As involved trade-offs among ES can be substantial, partial segregation with priority on specific services in designated zones is recommended.

Changes in the location and function of small water bodies in the upper Sanna River catchment—case study (SE Poland)

The article summarises the results of analyses of temporal and spatial changes in the location of small water bodies in the upper Sanna River catchment between the fifteenth and twenty-first centuries. The investigations were conducted on historical sources and cartographic data using GIS tools and inventory files. Natural (location of springs, groundwater depth, geomorphology of valleys), anthropogenic factors (quarries, excavations) and historical determinants of construction of the water reservoirs are presented. Additionally, changes in the economic (fish farming, mills), defence and industrial (paper and steel mills, bloomeries, fulleries) functions of the water bodies have been analysed. The changes in the functions of the water bodies were often influenced by the changing ownership. The results have application significance on a local and regional scale.

When timing matters-considering changing temporal structures in runoff response surfaces

Scenario-neutral response surfaces illustrate the sensitivity of a simulated natural system, represented by a specific impact variable, to systematic perturbations of climatic parameters. This type of approach has recently been developed as an alternative to top-down approaches for the assessment of climate change impacts. A major limitation of this approach is the underrepresentation of changes in the temporal structure of the climate input data (i.e., the seasonal and day-to-day variability) since this is not altered by the perturbation. This paper presents a framework that aims to examine this limitation by perturbing both observed and projected climate data time series for a future period, which both serve as input into a hydrological model (the HBV model). The resulting multiple response surfaces are compared at a common domain, the standardized runoff response surface (SRRS). We apply this approach in a case study catchment in Norway to (i) analyze possible changes in mean and extreme runoff and (ii) quantify the influence of changes in the temporal structure represented by 17 different climate input sets using linear mixed-effect models. Results suggest that climate change induced increases in mean and peak flow runoff and only small changes in low flow. They further suggest that the effect of the different temporal structures of the climate input data considerably affects low flows and floods (at least 21% influence), while it is negligible for mean runoff.

Impact of Short Duration Intense Rainfall Events on Sanitary Sewer Network Performance

Short duration intense rainfall causes an increase in rainfall derived infiltration and inflow (RDII) into aging sewer networks, which leads to Sanitary Sewer Overflows (SSOs). This study presents a generalised framework for assessing and mitigating the impacts of intense rainfall on sanitary sewer networks. The first part of the proposed framework involves a detailed hydraulic modelling to evaluate the performance of the sewer network. The second part deals with the development of SSO mitigation strategies based on Water Sensitive Urban Design (WSUD) approaches. This paper also demonstrates the application of the first part of the proposed framework for a case study catchment in Melbourne, Australia. The hydraulic performance of the case study sewer network during a wet and a dry year is presented. The analysis found that for the wet year, 11 manholes had sewer overflows, whereas 53 of 57 manholes in the network of 3.2 km had surcharges. Such a study will benefit the water authorities to develop mitigation strategies for controlling SSOs in their sewer systems.

Assessing the risk of phosphorus transfer to high ecological status rivers: Integration of nutrient management with soil geochemical and hydrological conditions

Agriculture has been implicated in the loss of pristine conditions and ecology at river sites classified as at ‘high ecological status’ across Europe. Although the exact causes remain unclear, diffuse phosphorus (P) transfer warrants consideration because of its wider importance for the ecological quality of rivers. This study assessed the risk of P loss at field scale from farms under contrasting soil conditions within three case-study catchments upstream of near-pristine river sites. Data from 39 farms showed P surpluses were common on extensive farm enterprises despite a lower P requirement and level of intensity. At field scale, data from 520 fields showed that Histic topsoils with elevated organic matter contents had low P reserves due to poor sorption capacities, and received applications of P in excess of recommended rates. On this soil type 67% of fields recorded a field P surplus of between 1 and 31kgha−1, accounting for 46% of fields surveyed across 10 farms in a pressured high status catchment. A P risk assessment combined nutrient management, soil biogeochemical and hydrological data at field scale, across 3 catchments and the relative risks of P transfer were highest when fertilizer quantities that exceeded current recommendations on soils with a high risk of mobilization and high risk of transport as indicated by topographic wetness index values. This situation occurred on 21% of fields surveyed in the least intensively managed catchment with no on-farm nutrient management planning and soil testing. In contrast, the two intensively managed catchments presented a risk of P transfer in only 3% and 1% of fields surveyed across 29 farms. Future agri-environmental measures should be administered at field scale, not farm scale, and based on soil analysis that is inclusive of OM values on a field-by-field basis.

The climate change effect on probable maximum precipitation in a catchment. A case study of the Karun river catchment in the Shalu bridge site (Iran)

Probable maximum precipitation (PMP) is assessed on the example of the Karun catchment (the Shalu bridge area). The climate change effects on PMP are investigated under three scenarios: A1B, A2, and B1. It is established that the PMP value for 24, 48, and 72 hours is 127, 170, and 185 mm, respectively. It is demonstrated that the PMP value will decrease by up to 5% under A1B scenario, and will increase by up to 5% and 10% under A2 and B1 scenarios, respectively.

Geochemical isotopic composition in the Loess Plateau and corresponding source analyses: A case study of China's Yangjuangou catchment.

Isotopic fractionation technology is widely used in identifying sources and the speciation of geochemical isotopic elements. With the increase in human activity, geochemical element transport by soil erosion has become the most critical environmental problem in the Loess Plateau, so tracing the geochemical element source would help in the identification and management of local soil erosion. In this study, we investigated the spatial distribution of carbon (C), nitrogen (N), oxygen (O), and hydrogen (H) isotopes in water and then further analyzed 13C and 15N in soil and vegetation to better understand the C and N sources and their biogeochemical cycling function in the Loess Plateau. Results showed that mean dual isotopic values of δ15N-NO3- and δ18O-NO3- in the watershed streams were 11.44±6.15‰ and -11.29±2.52‰, respectively, and that N wet deposition, fertilizers, and manure were the three main pollution sources. The mean dual isotopic value of δ13C in the water was -5.36±0.28‰, indicating that δ13C-DIC in the Yangjuangou Catchment of China's Loess Plateau is mainly controlled by carbonate weathering or soil erosion. The severe erosion in this region has typically occurred in grassy (C4) land-use types devoid of woody vegetation (C3), and this has led to a discrepancy in δ13C between soil and water. We found δ18O and δ2D in water to be -7.87±0.85‰ and -61.49±3.25‰, respectively, and to show a high positive correlation (r2=0.81). This suggests that summer rainstorms lead to soil erosion and runoff, which cause a wide range of isotopic values to occur across the Loess Plateau.

Landslide susceptibility mapping by using fuzzy logic: a case study of Cham-gardalan catchment, Ilam, Iran

Landslides are introduced as regional movements, which influence different engineering structures such as roads, railways, and dams and cause the person’s death. Identification of landslide zones may decrease the financial losses and human injuries or deaths. This study tries to achieve a landslide susceptibility mapping in Cham-gardalan catchment by weighting the main criteria and the membership functions of fuzzy logic. For this, we applied the best relationship function between the presence and absence of landslides as well as a collection of the elements. At first, the landslide points were identified by the means of some components those of satellite images, topographical (1:50,000) and geographical (1:100,000) maps, field visits, and Google Earth software followed by the preparation of landslide distribution maps. Then, all effective landslide factors such as percentage of slope, slope aspect, height, geology, land uses, distance from roads, distance from drainages, distance from breakage, and precipitation map have been utilized in order to conduct the fuzzy analyses. Landslide susceptibility map was performed by fuzzy operators (Gamma, Product, Sum, Or, And) in the study area. After fuzzificating and weighting, the effective criteria of landslides were determined through fuzzy Gamma operators with the landaus of 0.2, 0.5, 0.8, and 0.9 and by comparing final maps for making an appropriate model of landslide susceptibility mapping. The regional susceptibility map represents the landslide-prone areas in five categories those of very low, low, moderate, high, and very high. Our results indicated that among the applied operators, Gamma with landau of 0.9 can be used as an appropriate method for mapping the landslide susceptibility due to the suitable fuzzification of given criteria based on landslide distribution maps. In addition, the elements of road, percentage of slope, distance from drainage, and geology were recognized as the most important factors for occurring the landslides.

Assessing nitrogen fluxes from dairy farms using a modelling approach: A case study in the Moe River catchment, Victoria, Australia

Assessment of nitrogen (N) loss forms and pathways from farming systems is important for improved understanding of potential off-farm impacts on high value environmental assets. The objective of this study was to estimate N losses in different pathways in dairy systems across the range of climate, soil and farm management by using west Gippsland (Victoria, Australia) as case study area, and to characterise the sensitivity of the adopted model parameters. We combined the point scale models DairyMod and Howleaky to estimate dissolved N (DN) and particulate N (PN) loads in runoff, and N leaching (LN) in deep drainage from representative dairy farms in west Gippsland. Monte Carlo error propagation with Latin hypercube sampling was performed to identify sensitive model parameters and assess potential uncertainty in N load predictions. The combined model was capable of simulating climate-soil-animal-pasture management interactions and estimating DN, PN and LN at an annual scale; which were estimated at up to 18kg-Nha−1, 15kg-Nha−1 and 312kg-Nha−1, respectively. The combined model demonstrated that more intensive feeding as mixed ration, and nutrient budgeting that takes into account the fertiliser equivalent of recycled nutrients can achieve an increase in milk production by up to 13% and a decrease in N loads by up to 31% compared to the intensive system in the case study catchment. Soil type and farm management explained much of the variability (up to 76%) observed in LN and DN loads, whereas climate and soil type had significant influence on PN loads (62–77%). Year-to-year variation, particularly under dry conditions had a marked influence on N loads. Soil N, vegetation cover, rooting depth and soil maximum drainage rate must be well characterised in order to reduce potentially high uncertainty in the estimation of N losses in heterogeneous catchments.

Spatial patterns and environmental constraints on ecosystem services at a catchment scale

Improved understanding and prediction of the fundamental environmental controls on ecosystem service supply across the landscape will help to inform decisions made by policy makers and land-water managers. To evaluate this issue for a local catchment case study, we explored metrics and spatial patterns of service supply for water quality regulation, agriculture production, carbon storage, and biodiversity for the Macronutrient Conwy catchment. Methods included using ecosystem models such as LUCI and JULES, integration of national scale field survey datasets, earth observation products and plant trait databases, to produce finely resolved maps of species richness and primary production. Analyses were done with both 1×1km gridded and subcatchment data. A common single gradient characterised catchment scale ecosystem services supply with agricultural production and carbon storage at opposing ends of the gradient as reported for a national-scale assessment. Species diversity was positively related to production due to the below national average productivity levels in the Conwy combined with the unimodal relationship between biodiversity and productivity at the national scale. In contrast to the national scale assessment, a strong reduction in water quality as production increased was observed in these low productive systems. Various soil variables were tested for their predictive power of ecosystem service supply. Soil carbon, nitrogen, their ratio and soil pH all had double the power of rainfall and altitude, each explaining around 45% of variation but soil pH is proposed as a potential metric for ecosystem service supply potential as it is a simple and practical metric which can be carried out in the field with crowd-sourcing technologies now available. The study emphasises the importance of considering multiple ecosystem services together due to the complexity of covariation at local and national scales, and the benefits of exploiting a wide range of metrics for each service to enhance data robustness.

Towards a shared understanding of water security risks in the public and private sectors

This article investigates the knowledge and understanding of water risks, and how these are perceived in the private and public sectors. The article is based on a case-study catchment dominated by agricultural activity near Grabouw, in the Western Cape, South Africa. Starting with an overview of the hydrological context, the article follows with a discussion of the current water challenges and water-related risk perceptions of private- and public-sector actors. A conceptual framework is proposed, mapping the different water security risks. The article suggests that water management is improved when different actors acknowledge their shared water risks.

Achieving Net Zero Water in Severe Drought Prone Areas: A Case Study of Catchment, Storage, and Infiltration Optimization

Net zero water or water independent buildings capture rainwater to meet potable water demand. These systems require a careful calibration between catchment size, storage capacity, and infiltration area to achieve performance goals. In severe drought prone areas with wider variability of rainfall and long periods of scarcity, the precision of the calibration between these three variable is more narrowly defined to reach system resiliency. This paper analyzes a case study of a midsize office project in the severe drought prone area of Los Angeles, California that aims to achieve net zero water. The interrelation of the three variables are analyzed against daily precipitation over the last 10 years to identify dependencies and critical break points. The study finds that in severe drought prone conditions, storage size is relevant only up to a threshold closely mapped with demand. Net zero water system resiliency is accomplished through the precise interrelation of catchment area and infiltration capacity.

Assessment of soil erosion and sediment yield changes using erosion potential model: case study of Sangcharak catchment in Fars, Iran

The sediments resulting from the erosion of basins lead to the squandering of the soil, reduction of its infertility and decreasing of the quality of the water, and that is why the lifespan of the dams would be endangered because of the accumulation of the sediments. The goal of this research is to estimate erosion and sediment yield in Sangcharak basin by Erosion Potential Method (EPM), using GIS. For the purposes of quantifying the erosion intensity change has been done with the soil erosion maps from 2005 and recent state of erosion in 2014. Result of this paper showed that specific annual gross erosion on the Sangcharak territory was 775.34 (m³.km−2.y−1) in 2005 while in 2014 it was 914.24 (m³.km−2.y−1). Therefore, due to changes in intensity of erosion processes the specific annual gross erosion in catchment areas was increased by 138.89 (m³.km−2.y−1). Specific sediment yield in this area was 300.18 (m³.km−2.y−1) in 2005, while in 2014 was 349.01 (m³.km−2.y−1).

Applying Deterministic Distributed Hydrological Model for Stream Flow Data Reproduction. A Case Study of Cu De Catchment, Vietnam

Deterministic distributed model has been confirmed as one of highest performance model for representing the hydrological regime. By the capacity of covering all hydrological components in a catchment, this model is expected to be an effective tool for restoring the stream flow data, especially at lack of data catchment. In this study, a deterministic hydrological model - MIKE SHE (DHI) - is applied for reproducing the daily flow data in 20 years of Cu De river catchment, Viet Nam. The model is constructed over 425.2 Km2 with most of catchment's hydrological components. These components are set up in principle based on the characteristics of neighbouring catchment, Vu Gia - Thu Bon.