Literatura académica sobre el tema "Catchment loading"

Inorganic nitrogen loading was simulated using two dynamic catchment scale models, Integrated Nutrients in Catchments–Nitrogen (INCA-N) and the Generalized Watershed Loading Functions (GWLF). The simulated N loading was compared to a standard method to calculate annual loading using measured discharge and discharge-weighted concentrations. The main aim of the study was to compare these three estimation approaches with regards to their performance in hydrologically variable years in a small headwater catchment in southern Finland. Inter-annual variability of INCA-N and GWLF was compared with measured inorganic N concentrations at the catchment outlet. In years where snow melt dominates the annual discharge pattern all methods gave concurrent annual loading estimates. However, the loading estimates differ between the studied methods in years where large rainfall events in late summer or autumn dominate the annual discharge pattern, or when the model was not able to reproduce the spring discharge maximum properly. The results suggest that both models can be useful tools in estimating dissolved inorganic nitrogen loading from a catchment under changing climate conditions, providing that the key influencing driver, hydrology, is well captured.

Abstract. To examine the potential influence of terrestrially derived DOM on the Baltic Sea, a year-long study of dissolved organic matter (DOM) was performed in three river catchments in Sweden. One catchment drains into the Bothnian Sea, while two southern catchments drain into the Baltic proper. Dissolved organic carbon (DOC) concentrations were positively correlated with discharge from forested catchments over the year. While the overall concentrations of DOC were several times higher in the southern two catchments, higher discharge in the northern catchment resulted in the annual loadings of DOC being on the same order of magnitude for all three catchments. Biological oxygen demand (BOD) was used as a proxy for the lability of carbon in the system. The range of BOD values was similar for all three catchments, however, the ratio of BOD to DOC (an indication of the labile fraction) in Ume river was four times higher than in the southern two catchments. Total annual BOD loading to the Baltic Sea was twice as high in the northern catchment than in the two southern catchments. Lower winter temperatures and preservation of organic matter in the northern catchment combined with an intense spring flood help to explain the higher concentrations of labile carbon in the northern catchment. Lower lability of DOM as well as higher colour in the southern catchments suggest that wetlands (i.e. peat bogs) may be the dominant source of DOM in these catchments, particularly in periods of low flow. With climate change expected to increase precipitation events and temperatures across the region, the supply and quality of DOM delivered to the Baltic Sea can also be expected to change. Our results indicate that DOM supply to the Baltic Sea from boreal rivers will be more stable throughout the year, and potentially have a lower bioavailability.

Increased nutrient loading causes deterioration of receiving surface waters in areas of intensive agriculture. While nitrate and particulate phosphorus load can be efficiently controlled by reducing tillage frequency and increasing vegetation cover, many field studies have shown simultaneously increased loading of bioavailable phosphorus. In the latest phase of the Rural Programme of EU agri-environmental measures, the highest potential to reduce the nutrient loading to receiving waters were the maximum limits for fertilization of arable crops and retaining plant cover on fields with, e.g., no-till methods and uncultivated nature management fields. Due to the latter two measures, the area of vegetation cover has increased since 1995, suggesting clear effects on nutrient loading in the catchment scale as well. We modeled the effectiveness of agri-environmental measures to reduce phosphorus and nitrogen loads to waters and additionally tested the performance of the dynamic, process-based INCA-P (Integrated Nutrients in Catchments—Phosphorus) model to simulate P dynamics in an agricultural catchment. We concluded that INCA-P was able to simulate both fast (immediate) and slow (non-immediate) processes that influence P loading from catchments. Based on our model simulations, it was also evident that no-till methods had increased bioavailable P load to receiving waters, even though total P and total N loading were reduced.

Abstract. To examine the potential influence of terrestrially derived DOM on the Baltic Sea, a year-long study of dissolved organic matter (DOM) was performed in three river catchments in Sweden. One catchment drains into the Bothnian Sea, while two southern catchments drain into the Baltic Proper. Dissolved organic carbon (DOC) concentrations were positively correlated with discharge from forested catchments over the year and while the overall concentrations of DOC were several times higher in the southern two catchments, annual loading of DOC was on the same order for all three catchments, due to differences in discharge. Biological oxygen demand (BOD) was used as a proxy for the lability of carbon in the system. The range of BOD values was similar for all three catchments, however, the ratio of BOD to DOC (an indication of the labile fraction) in Ume älv was four times higher than in the southern two catchments. Total annual BOD loading to the Baltic Sea was twice as high in the northern catchment. Lower winter temperatures and preservation of organic matter in the northern catchment combined with an intense spring flood help to explain the higher concentrations of labile carbon in the northern catchment. Lower lability of DOM as well as higher colour in the southern catchments suggest that wetlands (i.e. peat bogs) may be the dominant source of DOM in these catchments, particularly in periods of low flow. With climate change expected to increase precipitation events and temperatures across the region, the supply and quality of DOM delivered to the Baltic Sea can also be expected to change. Our results indicate that DOM supply will be more stable throughout the year, and potentially have a lower bioavailability.

Lakes are the environmental and socioeconomic assets of Nepal. In the past few decades, land use and land cover (LULC) change has severely altered the lake ecosystems. The sediment and nutrients loading into the lakes have altered lake ecosystem significantly. This study analyzes the spatiotemporal variations of LULC change and examines its impact on lake environment of Phewa, Begnas and Rupa lakes during 1975–2018 by using Landsat satellite images and data from published literatures. Results showed that from 1975 to 2018, forest cover and agriculture land in catchments of all three lakes has decreased, while the built-up area has increased. LULC change in the catchment have bought the significant impact on the lake environment in terms of sedimentation rate, physiochemical parameters and biological environment. From 1975 to 2000 forest cover in lakes catchment has decreased, whereas the agriculture land has increased. At the same time, sediment and agriculture based nutrient loading into lakes has increased indicated by changes in sedimentation rate and alteration of physiochemical properties of the lake. From 2000 to 2018, forest and built-up area has increased while the agriculture land has decreased in lakes catchment. From 2000 to 2018, sedimentation rate of lakes has decreased compared to before 2000. Decreased sedimentation rate was interpreted due to increase in forest cover in the lake catchment. Increased nutrients loading into the lake during 2000 to 2018 has resulted serious eutrophication problem in lakes. Overall, this study suggests that the LULC change in the catchment have significant impact on lake environment.

Abstract The largest lakes of the River Tywa basin i.e. Strzeszowskie, Dołgie, Swobnica and Dłużec (north-west Poland, West Pomeranian Lakeland) were studied in the period 2008–2013, usually in a six week cycle. The aim of the study was to determine the degree of anthropogenic pressure on the lakes. Anthropogenic pressure was assessed against the natural vulnerability of lakes to degradation and the actual rate of eutrophication, with particular consideration of the catchment areas. Catchments of the studied lakes were classified as III class – catchment with moderate possibility of matter supply to lakes. Lakes Swobnica and Dłużec are characterised by low resistance to degradation. Lake Strzeszowskie is categorised as having moderate resistance and Lake Dołgie is non-resistant to degradation and highly susceptible to external pressure. The rate of eutrophication of lakes Strzeszowskie and Dłużec was found to be moderate, whereas lakes Dołgie and Swobnica show a high rate of eutrophication. The analysis of nutrient loading reaching the waters of the aforementioned lakes shows that the main area source is arable land, and the fundamental point source is the inflow of river waters to each of the analysed reservoirs. Nutrient loading supplied by the river is several times higher than area load. Such conditions require protective action to be taken within the catchment area and particularly, intensive implementation of good agricultural practice. In the studied lakes, there is a significant predominance of incoming nutrient loadings over dangerous and admissible loads.

A mass-balance approach is used to explore the effect of several hydrologic and geographic variables on humic matter concentrations in surface waters of Labrador–Ungava. Water-color measurements from 67 dilute oligotrophic lakes are used to evaluate model predictions of aquatic humus concentration from basin hydrology, catchment vegetation, and internal loss rates. The major trend in water color in the Labrador region — increasing north to south — results from differences in external humus loading from catchment vegetation and soils. Hydrologic influences on aquatic humus concentrations reside in the dilution of catchment drainage by direct precipitation to the lake — effective only when catchments are small — and in water residence time which controls losses due to mineralization and sedimentation.

Since 1989, nutrient loading of the Danish aquatic environment has been monitored in 270 Danish streams draining catchment areas differing in climate, physico-geographic and land usage. Diffuse nutrient loading from non-point sources (mainly agricultural) is now the main cause of eutrophication of the Danish aquatic environment; thus in 1993, diffuse sources accounted for 94% of riverine nitrogen loading and 52% of riverine phosphorus loading. Annual riverine total nitrogen (total-N) loading from diffuse sources during the period 1989-93 was on average 10 times greater in 66 small agricultural catchments (median 23.4 kg N ha−1) than in 9 natural catchments (median 2.2 kg N ha−1). Correspondingly, annual riverine total phosphorus (total-P) loading from diffuse sources was on average 3.5 times greater in the agricultural catchments (0.29 kg P ha−1) than in the natural catchments (0.07 kg P ha−1). The annual total-N and total-P load was found to increase with the proportion of agricultural land in the catchments. In 1993, intensive measurements of phosphorus load in 8 agricultural catchments showed that normal point sampling (fortnightly) underestimates annual total-P loading by a median of 37% as compared to that estimated by frequent sampling. Moreover, estimates of monthly total-P loading are even more biased, especially in late summer and early autumn (−50% to −65%).

Abstract Most semi-enclosed seas have experienced severe eutrophication owing to high nutrient loading from rivers during rapid population growth periods. In Japan, the coastal areas of some megacities (e.g. Tokyo and Osaka) experienced considerable economic growth during the 1960s–1970s. Therefore, determining the amount of nutrient loading during this period is essential to undertake measures for the conservation of coastal environments. However, determining the nutrient loading that occurred several decades ago is generally difficult owing to lacking water quality records. In this study, the nitrogen loading in the Yamato River catchment, an urbanized coastal catchment in Asia, for 80 years from the 1940s to the 2010s is reconstructed using the Soil and Water Assessment Tool. We considered factors such as population growth, wastewater treatment plant (WWTP) construction, and changes in land and fertilizer usage in different urbanization stages. Results show that the total nitrogen loading in the catchment peaked in the 1970s at 6616 tons yr−1 owing to untreated wastewater discharge and rapid increase in population growth. By reducing 57% of the nitrogen loading in the 2010s from the catchment, WWTPs have been instrumental in improving the water environment. The decrease in and integration of agricultural land has reduced nitrogen loading attributed to nonpoint sources; however, this reduction was not obvious because of the high fertilizer usage before the 2000s. Overall, the findings of this study provide a comprehensive understanding of the impact of rapid urbanization in an Asian coastal catchment on nitrogen loading during the high economic growth period in the past. This study will be useful for the long-term assessment of nutrient loading in other.

Abstract. Direct and indirect effects from agriculture, urbanization, and resource extraction have dramatically increased nutrient loading to aquatic inland and estuarine ecosystems. The capacity of a watershed to remove or retain nutrients is a function of biotic and abiotic conditions across the terrestrial-aquatic gradient including soil, groundwater, riparian zone, and surface water. The goal of this study was to identify proximate and ultimate controls on dissolved organic carbon and nutrient dynamics in small agricultural catchments. We analysed a five-year, high frequency water chemistry dataset from 3 catchments ranging from 2.3 to 10.8 km2 in northwestern France. Catchments differed in the relationship between hydrology and solute concentrations, associated with catchment characteristics such as hedgerow density, agricultural activity, and geology. The catchment with thicker soil and higher surface roughness appeared to have greater transient storage and residence time, buffering the catchment to fluctuations in water chemistry, reflected in relatively invariant carbon and nutrient chemistry across hydrologic conditions. Conversely, the catchments with smoother, thinner soils responded to both intra- and inter-annual hydrologic variation with high concentrations of PO43− and NH4+ during low flow conditions and strong increases in DOC, sediment, and particulate organic matter during high flows. Despite contrasting agricultural activity between catchments, the physical context (geology, topography, and land use) appeared to be the most important determinant of catchment solute dynamics based on principle components analysis. The influence of geology and accompanying topographic and geomorphological factors on elemental fluxes is both direct and indirect because the distribution of agricultural activity in these catchments is largely a consequence of the geologic and topographic context. This link between inherent catchment buffering capacity and probability of human disturbance provides a useful perspective for evaluating vulnerability of aquatic ecosystems to human disturbance.

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2011.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (p. 89-92).<br>Despite its tropical climate and abundant rainfall, Singapore is classified as a water scarce country. To protect its limited freshwater resources for both consumption and recreation, Singapore's Public Utilities Board (PUB) has created the Active, Beautiful, and Clean (ABC) campaign. In light of this program, the Massachusetts Institute of Technology (MIT) and Nanyang Technological University (NTU) in Singapore have partnered for various water quality research projects, including sampling of Choa Chu Kang, Bras Basah, Verde, and agricultural areas throughout Kranji Catchment in January 2011. Currently, bacterial levels in Kranji Reservoir are measured by sampling, which is labor intensive and delayed. As an alternative, a model of the surrounding watershed was constructed to estimate bacterial loading to the reservoir as driven by changing weather conditions. The watershed stream network was recreated using ArcSWAT, a version of the Soil and Water Assessment Tool used with geographic information system software. This model is based on a model previously created by Granger (2010). A major improvement is the specification of bacterial loading rates by land use and agriculture type. In order to estimate land-use-specific loading rates, numerous field samples were collected and analyzed for bacterial concentration in January 2011. Nonpoint source bacteria concentrations were estimated from field sample concentrations and applied to the land continuously in the model. Using weather data from January 2005 to February 2007, the model was run twice on a daily time step. The first run included only nonpoint sources, while the second included 23 sewage treatment plant point sources throughout the catchment. Simulated results were compared to independent samples taken in 2009 by Nshimyimana (2010) and indicate a general agreement of order of magnitude, with most measured values within the predicted range. The magnitudes of the nonpoint source run achieved a better fit with field data, although the point source run produced concentration frequency distributions that are approximately lognormal, a characteristic typical of environmental bacteria concentration distributions.<br>by Ryan Christopher Bossis.<br>M.Eng.

Pollutants follow various subsurface and surface water pathways from sources within a catchment to its outlet and may cause detrimental effects on downstream water quality and ecosystems. Along their different transport pathways through a catchment, pollutants may be attenuated subject to different physical and biogeochemical processes. In this thesis, physical process effects on such catchment-scale pollutant transport and attenuation, resulting coastal pollutant loading and its efficient abatement are investigated. For this purpose, pollutant transport-attenuation is modeled both generically using a Lagrangian Stochastic Advective-Reactive (LaSAR) approach and site specifically for the Swedish Norrström basin using the GIS-based dynamic nitrogen transport-attenuation model POLFLOW. Furthermore, the role of such modeling for catchment-scale pollutant abatement is also investigated by use of economic optimization modeling. Results indicate that appropriate characterization of catchment-scale solute transport and attenuation processes requires accurate quantification of the specific solute pathways from different sources in a catchment, through the subsurface and surface water systems of the catchment, to the catchment outlet. The various physical processes that act on solute transported along these pathways may be quantified appropriately by use of relevant solute travel time distributions for each water subsystem that the pathways cross through the catchment. Such distributions capture the physical solute travel time variability from source to catchment outlet and its effects on reactive pollutant transport. Results of this thesis show specifically that neglect of such physical solute travel time variability in large-scale models of nitrogen transport and attenuation in catchments may yield misleading model estimates of nitrogen attenuation rates. Results for nitrogen abatement optimization in catchments further indicate that inefficient solutions for coastal nitrogen load reduction may result from simplifying physical transport assumptions made in different catchment-scale nitrogen transport-attenuation models. Modeling of possible future nitrogen management scenarios show also that slow nitrogen transport and reversible mass transfer processes in the subsurface water systems of catchments may greatly delay and temporally redistribute coastal nitrogen load effects of inland nitrogen source abatement over decades or much longer. Achievement of the national Swedish environmental objective to reduce the anthropogenic coastal nitrogen loading by 30% may therefore require up to a 40% reduction of both point sources, for achieving a fast coastal load response, and diffuse sources, for maintaining the coastal load reduction also in the long term.<br>QC 20100908

The Lake Clearwater catchment, in the Canterbury high country of New Zealand, has a native ecosystem that is adapted to low nutrient conditions. Wetlands in the catchment are identified by the Department of Conservation’s Arawai Kākāriki Wetland Restoration Programme as one of three important endemic wetland types in New Zealand. Uncertainty regarding diffuse nutrient load from agriculture into the lake and wetland ecosystems is limiting effective management of the catchment. This study investigated hydrological processes and nitrogen and phosphorus concentrations to improve knowledge of the sources, characteristics and magnitude of nutrient loading from agricultural land use in this 46 km2 high country catchment. Relevant hydrological data and literature pertaining to the catchment was extensively reviewed. In addition, flow for five key surface waterways was continuously logged at ten sites for 2 years. Concurrently, nutrient concentrations for total nitrogen, nitrate, ammoniacal nitrogen, total phosphorus and dissolved reactive phosphorus were measured at ten surface water sites and three groundwater sites. Total nitrogen and phosphorus load from farmland was calculated from annual flow and median concentrations for four waterways: farmland perennial stream runoff, farmland ephemeral stream runoff, a wetland channel below the farmed hillslope and the lake outlet. Similarly, total nitrogen and phosphorus load for unfarmed land was calculated from the flow and median concentration of two un-impacted perennial streams. Total nitrogen and phosphorus mass balances were calculated and used to estimate subsurface nutrient load and runoff volume from the farmed hillslope. Estimates of subsurface runoff were also made using Darcy’s equation and a water balance. Nutrient load predictions from the Catchment Land Use for Environmental Sustainability (CLUES) model were compared to measured loads. Nutrients were found to be elevated downstream of farmland, especially nitrogen, which was often above relevant guidelines and typical concentrations in upland waterways in Canterbury. Nitrate in farmland subsurface runoff was elevated and was estimated to contribute 52% of total nitrogen yield from farmland. Total nitrogen yield (1.96-2.94 kg ha-1 year-1) for farmed land was comparable to minimum values for pastoral land use in literature but total phosphorus yield (0.093-0.123 kg ha-1 year-1) was well below published values. The range in yield estimates is due to subtraction of a high and a low estimate of natural baseline yield from the measured in-stream yield. Total nitrogen export from the lake (2518 kg year-1) was greater than estimated input (1375 kg year-1) from farmed and non-farmed land indicating an additional source of nitrogen into Lake Clearwater. Total phosphorus export from Lake Clearwater of 58 kg year-1 was 24% less than total estimated loads into the lake (76 kg year-1) from farmed and non-farmed land. Phosphorus was not often above relevant guidelines and the median total nitrogen to total phosphorus ratio in Lake Clearwater (49:1) indicated phosphorus is the limiting nutrient in the lake. Because phosphorus was less elevated relative to nitrogen, an increase in phosphorus inputs could have a greater effect on productivity in the wetland and lake. With corrected land use information, total nitrogen loads predicted by the CLUES model were reasonable but total phosphorus loads were greatly overestimated. Investigation into potential impacts of the elevated nutrient loads described in this study on receiving native ecosystems is recommended to inform conservation efforts.

<p><span lang="EN-GB" style="font-size: 12.0pt<br>line-height:150%<br>font-family:&quot<br>Times New Roman&quot<br>,&quot<br>serif&quot<br>">The most significant human impacts on the hydrological system are due to land-use change. The conversion of land to agricultural, mining, industrial, or residential uses significantly alters the hydrological characteristics of the land surface and modifies pathways and rates of water flow. If this occurs over large or critical areas of a catchment, it can have significant short and long-term impacts, on the quality of water. While there are methods available to quantify the pollutants in surface water, methods of linking non-point source pollution to water quality at catchment scale are lacking. Therefore, the research presented in this thesis investigated modelling techniques to estimate the effect of land-cover type on water quality. The main goal of the study was to contribute towards improving the understanding of how different land-covers in an urbanizing catchment affect surface water quality. The aim of the research presented in this thesis was to explain how the quality of surface runoff varies on different land-cover types and to provide guidelines for minimizing water pollution that may be occurring in the Kuils-Eerste River catchment. The research objectives were<br>(1) to establish types and spatial distribution of land-cover types within the Kuils-Eerste River catchment, (2) to establish water quality characteristics of surface runoff from specific land-cover types at the experimental plot level, (3) to establish the contribution of each land-cover type to pollutant loads at the catchment scale.<span style="mso-spacerun:yes"> </span><span lang="EN-GB" style="font-size: 12.0pt<br>line-height:150%<br>font-family:&quot<br>Times New Roman&quot<br>,&quot<br>serif&quot<br>">Land-cover characteristics and water quality were investigated using GIS and Remote Sensing tools. The application of these tools resulted in the development of a land-cover map with 36 land classifications covering the whole catchment. Land-cover in the catchment is predominantly agricultural with vineyards and grassland covering the northern section of the catchment. Vineyards occupy over 35% of the total area followed by fynbos (indigenous vegetation) (12.5 %), open hard rock area (5.8 %), riparian forest (5.2 %), mountain forest<span style="mso-spacerun:yes">&nbsp<br>&nbsp<br></span>(5 %), dense scrub (4.4 %), and improved grassland (3.6 %). The residential area covers about 14 %. Roads cover 3.4 % of the total area. </span><span lang="EN-GB" style="font-size: 12.0pt<br>line-height:150%<br>font-family:&quot<br>Times New Roman&quot<br>,&quot<br>serif&quot<br>">Surface runoff is responsible for the transportation of large quantities of pollutants that affect the quality of water in the Kuils-Eerste River catchment. The different land-cover types and the distribution and concentration levels of the pollutants are not uniform. Experimental work was conducted at plot scale to understand whether land-cover types differed in their contributions to the concentration of water quality attributes emerging from them.<span style="color:black"> Four plots each with a length of 10 m to 12 m and 5 m width were set up. Plot I was set up on open grassland, Plot II represented the vineyards, Plot III covered the mountain forests, and Plot IV represented the fynbos land-cover.</span> Soil samples analyzed from the experimental plots fell in the category of sandy soil (Sa) with the top layer of Plot IV (fynbos) having loamy sand (LmSa). The soil particle sizes range between fine sand (59.1 % and 78.9 %) to coarse sand (between 7 % and 22 %). The content of clay and silt was between 0.2 % and 2.4 %. Medium sand was between 10.7 % and 17.6 %. In terms of vertical distribution of the particle sizes, a general decrease with respect to the size of particles was noted from the top layer (15 cm) to the bottom layer (30 cm) for all categories of the particle sizes. There was variation in particle size with depth and location within the experimental plots.</span><span lang="EN-GB" style="font-size: 12.0pt<br>line-height:150%<br>font-family:&quot<br>Times New Roman&quot<br>,&quot<br>serif&quot<br>">Two primary methods of collecting water samples were used<br>grab sampling and composite sampling. The quality of water as represented by the samples collected during storm events during the rainfall season of 2006 and 2007 was<span style="mso-spacerun:yes">&nbsp<br></span>used to establish <span style="mso-spacerun:yes">&nbsp<br></span>water quality characteristics for the different land-cover types. The concentration of total average suspended solids was highest in the following land-cover types, cemeteries (5.06 mg L^-1), arterial roads/main roads (3.94 mg L^-1), low density residential informal squatter camps (3.21 mg L^-1) and medium density residential informal townships (3.21 mg L^-1). Chloride concentrations were high on the following land-cover types, recreation grass/ golf course (2.61 mg L^-1), open area/barren land (1.59 mg L^-1), and improved grassland/vegetation crop (1.57 mg L^-1). The event mean concentration (EMC) values for NO₃-N were high on commercial mercantile (6 mg L^-1) and water channel (5 mg L^-1). The total phosphorus concentration mean values recorded high values on improved grassland/vegetation crop (3.78 mg L^-1), medium density residential informal townships (3mgL^-1) and low density residential informal squatter camps (3 mg L^-1). Surface runoff may also contribute soil particles into rivers during rainfall events, particularly from areas of disturbed soil, for example areas where market gardening is taking place. The study found that different land cover types contributed differently to nonpoint source pollution. </span><span lang="EN-GB" style="font-size: 12.0pt<br>line-height:150%<br>font-family:&quot<br>Times New Roman&quot<br>,&quot<br>serif&quot<br>">A GIS model was used to estimate the diffuse pollution of five pollutants (chloride, phosphorus, TSS, nitrogen and NO₃-N) in response to land cover variation using water quality data. The GIS model linked land cover information to diffuse nutrient signatures in response to surface runoff using the Curve Number method and EMC data were developed. Two models (RINSPE and N-SPECT) were used to estimate nonpoint source pollution using various GIS databases. The outputs from the GIS-based model were compared with recommended water quality standards. It was found that the RINSPE model gave accurate results in cases where NPS pollution dominate the total pollutant inputs over a given land cover type. However, the N-SPECT model simulations were too uncertain in cases where there were large numbers of land cover types with diverse NPS pollution load. All land-cover types with concentration values above the recommended national water quality standard were considered as areas that needed measures to mitigate the adverse effects of nonpoint pollution. </span><span lang="EN-GB" style="font-size: 12.0pt<br>line-height:150%<br>font-family:&quot<br>Times New Roman&quot<br>,&quot<br>serif&quot<br>">The expansion of urban areas and agricultural land has a direct effect on land cover types within the catchment. 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Lake Ringsjön, located in south of Sweden, has been subject of eutrophication since 1950s and received several restoration efforts. Latest restoration effort, “Project Ringsjön”, was proposed in 2003 to improve lake condition against eutrophication by reducing nutrient concentration. This study was done to assess the nutrient loading into the lake from the catchment of Hörbyån Creek, which is discharging into the lake from southeast. Study addresses the nutrient loading conditions from Hörbyån Creek before and after the implementation of “Project Ringsjön” in 1998 and 2010 respectively. Thus a water quality analysis was performed to observe the changes in total nitrogen and total phosphorus concentration in Hörbyån Creek between these years. Effort was also made to investigate nutrients contribution of different watersheds in the catchment. This study also addresses the effect of seasonal variability and land use on nutrient loading. In order to achieve objectives, annual and monthly water quality modelling was performed on the river. HEC-RAS software was used to simulate water quality variables loading from catchment into the lake, such as nitrates, nitrite, ammonium, organic nitrogen, inorganic phosphorus and orthophosphate. Results indicated increase in average annual total nitrogen concentration from 4.18 mg/l to 4.56 mg/l and reduction in average annual total phosphorus concentration from 0.165 mg/l to 0.083 mg/l in the water discharging into the lake from catchment. The watershed occupying mostly agriculture area was observed to have maximum nutrients contribution, which might be due to high fertilizer leakage. It was also observed that maximum nutrient loading was taking place in November and March; probably due to high runoff generated from precipitation and snow melting that carried additional nutrients to the water bodies. Results also indicated that the studied catchment area was contributing high nutrient concentration for eutrophication in both years; however, there was small decrease in total phosphorus concentration in 2010 compare to 1998.

Glenbrook Lagoon, an 8 hectare lake receiving rainfall runoff from a residential catchment, is experiencing nutrient enrichment problems expressed as excessive aquatic plant presence. This study aims to assess the relative nutrient contribution of the total system compartments, including catchment loading, water column, aquatic plants and surface sediment. This information is utilised in the formulation of management strategies which may produce a sustainable nutrient reduction and general improvement in the system. The total nutrient content of the aquatic system was determined to be high in comparison with the present nutrient loading from the catchment. The ideal management case considers nutrient reduction of the surface sediment compartment firstly, followed by the aquatic plant community, with the water column and catchment influence as relatively low priority compartments. Various strategies for managing these are proposed. The total system benefits of the ideal management case are reductions in nutrients, aquatic plant biovolume and suspended solid loading. Unavoidable constraints placed upon the ideal management case include the excessive aquatic plant presence restricting accessability to the surface sediment for dredging. The resulting best management case requires aquatic plant eradication prior to sediment management, with the total system benefits associated with the ideal management case being retained.<br>Master of Science (Hons)

Intermittently Closed and Open Lake Lagoons (ICOLLs) are very common along the southern NSW coastline. Expanding urban populations are expanding and these systems are under increasing pressure from anthropogenic activities that change landscape processes and significantly alter the amounts of organic and inorganic constituents entering their waters. Once efficient cycling of nutrients in ICOLLs is overcome, the symptoms of eutrophication establish and the entire ecosystem suffers. These systems have great ecological, social, and economic values that require insightful, well balanced, and educated management to promote sustainable use of these often-sensitive areas. Corunna and Nangudga Lake are ICOLLs in the Eurobodalla Shire on the south coast of NSW. These two ICOLLs receive discharges from catchments covered by native vegetation and grassland. The primary objective of this research component was to quantify catchment exports of total nitrogen (TN), total phosphorus (TP), suspended solids (SS), particulate organic matter (POM) and dissolved organic carbon (DOC) from three small coastal sub catchments that deliver constituents into Corunna and Nangudga Lakes. As part of this investigation the fates of catchment loads in the ICOLLs were established focusing on the lakes water column response to catchment loads and the biogeochemical cycling of nitrogen and phosphorus in sediments.

Vistula Lagoon as a part of the coastal zone translates nutrient load from catchment to the Baltic Sea. Catchments of the Primorskaya River (small settlements, mostly agricultural area, 120 km2) and Banówka-Mamonovka River (transboundary catchment between Russia and Poland, relatively big settlements, food production enterprises, agricultural activity, 490 km2) were selected as test ones for the Vistula Lagoon catchment (23 870 km2). Assessment of the retention of total nitrogen and phosphorus in the catchment and the transformation of nutrient load from anthropogenic sources while passing the catchment were studied by using open source numerical modeling tools. Initial data comprises the geomorphic characteristics, river net data, information on land use and nutrient point sources, time series of temperature, precipitation. Runoff was simulated by hydrological model HYPE considering the evaporation and infiltration into the soil. Retention and transport of nutrients were accessed using the model FyrisNP. Source apportionment was made for the nutrient load discharging from both catchments to the Vistula Lagoon. The greatest amount of nutrients in final discharge is coming from the arable land (50-80%), point sources constitute a smaller proportion (5-30%). The results will be used to obtain the first order approximation of the nutrient load from other small rivers of the Vistula Lagoon catchment and from the biggest river in the area, the Pregolya River (15 300 km2) by analogy.

Vistula Lagoon as a part of the coastal zone translates nutrient load from catchment to the Baltic Sea. Catchments of the Primorskaya River (small settlements, mostly agricultural area, 120 km2) and Banówka-Mamonovka River (transboundary catchment between Russia and Poland, relatively big settlements, food production enterprises, agricultural activity, 490 km2) were selected as test ones for the Vistula Lagoon catchment (23 870 km2). Assessment of the retention of total nitrogen and phosphorus in the catchment and the transformation of nutrient load from anthropogenic sources while passing the catchment were studied by using open source numerical modeling tools. Initial data comprises the geomorphic characteristics, river net data, information on land use and nutrient point sources, time series of temperature, precipitation. Runoff was simulated by hydrological model HYPE considering the evaporation and infiltration into the soil. Retention and transport of nutrients were accessed using the model FyrisNP. Source apportionment was made for the nutrient load discharging from both catchments to the Vistula Lagoon. The greatest amount of nutrients in final discharge is coming from the arable land (50-80%), point sources constitute a smaller proportion (5-30%). The results will be used to obtain the first order approximation of the nutrient load from other small rivers of the Vistula Lagoon catchment and from the biggest river in the area, the Pregolya River (15 300 km2) by analogy.

The catchment area of the Pregolya River is about 65% of the Vistula Lagoon drainage basin and occupied by Russia and Poland in approximately equal proportions. Nutrient load from the catchment largely controls the eutrophication processes of the lagoon ecosystem. Open statistical data (2011-2014) were used for evaluating the nutrient loads. At present, the nutrient load from the major anthropogenic sources (population, livestock, poultry and crop production) is 53,267 tons N/year and 16,424 tons P/year in the Pregolya River catchment. This results in loads of 23,032 tons N/year and 2,819 tons P/year when the removal of nutrients by the harvest is taken into account. It was found that the load from anthropogenic sources in the Polish part of the catchment higher than in the Russian part by a factor of three times for nitrogen and two times for phosphorus. The reason for this is that Polish territory is relatively more agriculturally developed. In the Kaliningrad Oblast agriculture declined in the 1990-2000's and now about 50% of arable lands are not used, which creates a potential for development. Currently there is a positive trend of the agriculture development and the "Strategy of socio-economic development of the Kaliningrad Oblast until 2020" is expected to increase arable land by 70%, the number of cattle and pigs by factors of 3.5 and 9.5, respectively. This creates a potential for significant increases of the nutrients loading and eutrophication of the Vistula Lagoon. The nutrient load from the anthropogenic sources in the Russian part of the catchment can be compensated greatly by using the manure as organic fertilizer replacing mineral fertiliser, as at present time 40% of available arable land in the Kaliningrad Oblast is sufficient for utilization of all manure originated locally at the maximum fertilization rate recommended by HELCOM. At the same time more than 80% of the wastewater in Kaliningrad Oblast is not sufficiently treated. This poses a great potential for nutrient load reduction. The calculations showed that equipment of Kaliningrad city with the modern treatment facilities will reduce the nutrient load by 1,400 tons N/year and 290 tons P/year.

The catchment area of the Pregolya River is about 65% of the Vistula Lagoon drainage basin and occupied by Russia and Poland in approximately equal proportions. Nutrient load from the catchment largely controls the eutrophication processes of the lagoon ecosystem. Open statistical data (2011-2014) were used for evaluating the nutrient loads. At present, the nutrient load from the major anthropogenic sources (population, livestock, poultry and crop production) is 53,267 tons N/year and 16,424 tons P/year in the Pregolya River catchment. This results in loads of 23,032 tons N/year and 2,819 tons P/year when the removal of nutrients by the harvest is taken into account. It was found that the load from anthropogenic sources in the Polish part of the catchment higher than in the Russian part by a factor of three times for nitrogen and two times for phosphorus. The reason for this is that Polish territory is relatively more agriculturally developed. In the Kaliningrad Oblast agriculture declined in the 1990-2000's and now about 50% of arable lands are not used, which creates a potential for development. Currently there is a positive trend of the agriculture development and the "Strategy of socio-economic development of the Kaliningrad Oblast until 2020" is expected to increase arable land by 70%, the number of cattle and pigs by factors of 3.5 and 9.5, respectively. This creates a potential for significant increases of the nutrients loading and eutrophication of the Vistula Lagoon. The nutrient load from the anthropogenic sources in the Russian part of the catchment can be compensated greatly by using the manure as organic fertilizer replacing mineral fertiliser, as at present time 40% of available arable land in the Kaliningrad Oblast is sufficient for utilization of all manure originated locally at the maximum fertilization rate recommended by HELCOM. At the same time more than 80% of the wastewater in Kaliningrad Oblast is not sufficiently treated. This poses a great potential for nutrient load reduction. The calculations showed that equipment of Kaliningrad city with the modern treatment facilities will reduce the nutrient load by 1,400 tons N/year and 290 tons P/year.

Abstract Oil and gas pipelines are subjected to multiple types of geohazards which cause pipeline failures (loss of containment); two of the most common types occur at watercourse crossings and at landslides. At watercourse crossings, the most common geohazard which causes pipeline failures is flooding during which excessive scour may result in the exposure of the buried pipeline and if the exposure results in a free spanning pipeline, then this may fail due to fatigue caused by cyclic loading from vortex-induced vibration. Fortunately the free span length and water velocity combinations that lead to failure can be defined and can be used to identify the flood discharge that should be monitored for in order to trigger actions to manage the hazard and avoid failure. Most watercourse crossings in a pipeline network are on ungauged watercourses and necessitate the use of a proxy gauged watercourse. The “proxy” gauged watercourse is used to infer whether flooding is occurring on the ungauged crossing, and the owner can take appropriate actions. Often the proxy gauged watercourse is too far away or the watercourse may not be representative of the crossing of concern (e.g. large difference in the drainage areas). Real-time rainfall data can be used in conjunction with streamflow monitoring to determine when extreme precipitation has occurred within the ungauged watercourses catchment which may result in flooding. Where pipelines cross landslide prone areas, large scale movements can be initiated, or slow on-going movement rates increased when extreme rainfall occurs. The definition of the extreme rainfall event for slope sites is the key component of providing a suitable warning of potentially dangerous conditions; shallow slides can be caused by short term events from sub-hourly to 3 day duration precipitation events whereas large deep seated (creeping) landslides can be driven by annual and intra-annual rainfall amounts. Monitoring of real time rainfall can be used to determine when extreme rainfall occurs at a landslide site. The density of in-situ weather stations collecting real-time rainfall data prevents the application along remote sections of pipeline routes and within large sections of Canada. Gridded real time rainfall from quantitative precipitation estimations which integrate a multiple data sources including in-situ, numerical weather prediction, satellite and weather radar, can be used to overcome this problem and provide warnings when pre-determined rainfall thresholds are exceeded on a site-specific basis.

Stormwater management is an ongoing challenge in the United States and the world at-large. As state and municipal agencies grapple with conflicting interests like encouraging land development, complying with permits to control stormwater discharges, “urban stream syndrome” effects, and charges to steward natural resources for the long-term, some agencies may turn to constructed wetlands (CWs) as aesthetically pleasing and functional natural analogs for attenuating pollution delivered by stormwater runoff to rivers and streams. Constructed wetlands retain pollutants via common physical, physicochemical, and biological principles such as settling, adsorption, or plant and algae uptake. The efficacy of constructed wetlands for pollutant attenuation varies depending on many factors such as flow rate, pollutant loading, maintenance practices, and design features. In 2018, the culmination of efforts by Clackamas Water Environment Services and others led to the opening of the Carli Creek Water Quality Project, a 15-acre constructed wetland adjacent to Carli Creek, a small, 3500-ft tributary of the Clackamas River in Clackamas County, OR. The combined creek and constructed wetland drain an industrialized, 438-acre, impervious catchment. The wetland consists of a linear series of a detention pond and three bioretention treatment cells, contributing a combined 1.8 acres of treatment area (a 1:243 ratio with the catchment) and 3.3 acre-feet of total runoff storage. In this study, raw pollutant concentrations in runoff were evaluated against International Stormwater BMP database benchmarks and Oregon Water Quality Criteria. Concentration and mass-based reductions were calculated for 10 specific pollutants and compared to daily precipitation totals from a nearby precipitation station. Mass-based reductions were generally higher for all pollutants, largely due to runoff volume reduction on the treatment terrace. Concentration-based reductions were highly variable, and suggested export of certain pollutants (e.g., ammonia), even when reporting on a mass-basis. Mass load reductions on the terrace for total dissolved solids, nitrate+nitrite, dissolved lead, and dissolved copper were 43.3 ± 10%, 41.9 ± 10%, 36.6 ± 13%, and 43.2 ± 16%, respectively. E. coli saw log-reductions ranging from -1.3 — 3.0 on the terrace, and -1.0 — 1.8 in the creek. Oregon Water Quality Criteria were consistently met at the two in-stream sites on Carli Creek for E. coli with one exception, and for dissolved cadmium, lead, zinc, and copper (with one exception for copper). However, dissolved total solids at the downstream Carli Creek site was above the Willamette River guidance value 100 mg/L roughly 71% of the time. The precipitation record during the study was useful for explaining certain pollutant reductions, as several mechanisms are driven by physical processes, however it was not definitive. The historic rain/snow/ice event in mid-February 2021 appeared to impact mass-based reductions for all metals. Qualitatively, precipitation seemed to have the largest effect on nutrient dynamics, specifically ammonia-nitrogen. Determining exact mechanisms of pollutant removals was outside the scope of this study. An improved flow record, more targeted storm sampling, or more comprehensive nutrient profiles could aid in answering important questions on dominant mechanisms of this new constructed wetland. This study is useful in establishing a framework and baseline for understanding this one-of-a-kind regional stormwater treatment project and pursuing further questions in the future.