1.
Baresel, Christian, et al.
(författare)
Uncertainty-Accounting Environmental Policy and Management of Water Systems
2007
Ingår i: Environmental Science & Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 41:10, s. 3653–3659-
Tidskriftsartikel (refereegranskat) abstract
Environmental policies for water quality and ecosystemmanagement do not commonly require explicit stochasticaccounts of uncertainty and risk associated with thequantification and prediction of waterborne pollutant loadsand abatement effects. In this study, we formulate andinvestigate a possible environmental policy that does requirean explicit stochastic uncertainty account. We compareboth the environmental and economic resource allocationperformance of such an uncertainty-accounting environmentalpolicy with that of deterministic, risk-prone and riskaverseenvironmental policies under a range of differenthypothetical, yet still possible, scenarios. The comparisonindicates that a stochastic uncertainty-accountingpolicy may perform better than deterministic policies overa range of different scenarios. Even in the absence ofreliable site-specific data, reported literature values appearto be useful for such a stochastic account of uncertainty.
2.
Cantoni, Jacopo, et al.
(författare)
Legacy contributions to diffuse water pollution : Data-driven multi-catchment quantification for nutrients and carbon
2023
Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 879, s. 163092-
Tidskriftsartikel (refereegranskat) abstract
Legacy pollutants are increasingly proposed as possible reasons for widespread failures to improve water quality, de -spite the implementation of stricter regulations and mitigation measures. This study investigates this possibility, using multi-catchment data and relatively simple, yet mechanistically-based, source distinction relationships between water discharges and chemical concentrations and loads. The relationships are tested and supported by the available catch -ment data. They show dominant legacy contributions for total nitrogen (TN), total phosphorus (TP) and total organic carbon (TOC) across catchment locations and scales, from local to country-wide around Sweden. Consistently across the study catchments, close relationships are found between the legacy concentrations of TN and TOC and the land shares of agriculture and of the sum of agriculture and forests, respectively. The legacy distinction and quantification capabilities provided by the data-driven approach of this study could guide more effective pollution mitigation and should be tested in further research for other chemicals and various sites around the world.
3.
Destouni, Georgia, et al.
(författare)
Distinguishing active and legacy source contributions to stream water quality : Comparative quantification for chloride and metals
2021
Ingår i: Hydrological Processes. - : Wiley. - 0885-6087 .- 1099-1085. ; 35:7
Tidskriftsartikel (refereegranskat) abstract
Hydrochemical constituents in streams may originate from currently active sources at the surface and/or legacy sources from earlier surface inputs, waste deposits and land contamination. Distinction and quantification of these source contributions are needed for improved interpretation of tracer data and effective reduction of waterborne environmental pollutants. This article develops a methodology that recognizes and quantifies some general mechanistic differences in stream concentration and load behavior versus discharge between such source contributions. The methodology is applied to comparative analysis of stream concentration data for chloride (Cl-), copper (Cu), lead (Pb), and zinc (Zn), and corresponding data for water discharge, measured over the period 1990-2018 in multiple hydrological catchments (19 for Cl-, 11 for Cu and Zn, 10 for Pb) around the major Lake Malaren in Sweden. For Cl-, the average load fraction of active sources is quantified to be 19%, and the average active and legacy concentration contributions as 2.9 and 11 mg/L, respectively. For the metals, the average active load fractions at outlets are 1%-3% over all catchments and 9%-14% in the relatively few catchments with mixed metal sources. Average active and legacy concentration contributions are 0.14 and 3.2 mu g/L for Cu, 0.05 and 1.5 mu g/L for Pb, and 1.4 and 12 mu g/L for Zn, respectively. This multi-catchment analysis thus indicates a widespread prevalence of legacy sources, with greater legacy than active concentration contributions for both Cl- and the metals, and active contributions playing a greater role for chloride than for the metals. The relatively simple first-order methodology developed and applied in the study can be used to screen commonly available stream monitoring data for possible distinction of active and legacy contributions of any hydrochemical constituent in and across various hydrological catchment settings.
4.
Frampton, Andrew, et al.
(författare)
Permafrost degradation and subsurface-flow changes caused by surface warming trends
2012
Ingår i: Hydrogeology Journal. - : Springer Science and Business Media LLC. - 1431-2174 .- 1435-0157. ; 21:1, s. 271-280
Tidskriftsartikel (refereegranskat) abstract
Change dynamics of permafrost thaw, andassociated changes in subsurface flow and seepage into surface water, are analysed for different warming trends in soil temperature at the ground surface with a three-phase two-component flow system coupled to heat transport. Changes in annual, seasonal and extreme flows are analysed for three warming-temperature trends, representing simplified climate change scenarios. The results support previous studies of reduced temporal variability of groundwater flow across all investigated trends. Decreased intra-annual flow variability may thus serve asan early indicator of permafrost degradation before longer term changes in mean flows are notable. This is advantageous since hydrological data are considerably easier to obtain, may be available in longer time series, and generally reflect larger-scale conditions than direct permafrost observations. The results further show that permafrost degradation first leads to increasing water discharge, which then decreases as the permafrost degradation progresses further to total thaw. The most pronounced changes occur for minimum annual flows. The configuration considered represents subsurface discharge from a generic heterogeneous soil-type domain.
5.
Khazaei, Bahram, et al.
(författare)
Climatic or regionally induced by humans? Tracing hydro-climatic and land-use changes to better understand the Lake Urmia tragedy
2019
Ingår i: Journal of Hydrology. - : Elsevier BV. - 0022-1694 .- 1879-2707. ; 569, s. 203-217
Tidskriftsartikel (refereegranskat) abstract
Lake Urmia-a shallow endemic hypersaline lake in northwest Iran-has undergone a dramatic decline in its water level (WL), by about 8 m, since 1995. The primary cause of the WL decline in Lake Urmia has been debated in the scientific literature, regarding whether it has been predominantly driven by atmospheric climate change or by human activities in the watershed landscape. Using available climate, hydrological, and vegetation data for the period 1981-2015, this study analyzes and aims to explain the lake desiccation based on other observed hydro-climatic and vegetation changes in the Lake Urmia watershed and classical exploratory statistical methods. The analysis accounts for the relationships between atmospheric climate change (precipitation P, temperature T), and hydrological (soil moisture SM, and WL) and vegetation cover (VC; including agricultural crops and other vegetation) changes in the landscape. Results show that P, T, and SM changes cannot explain the sharp decline in lake WL since 2000. Instead, the agricultural increase of VC in the watershed correlates well with the lake WL change, indicating this human-driven VC and associated irrigation expansion as the dominant human driver of the Lake Urmia desiccation. Specifically, the greater transpiration from the expanded and increasingly irrigated agricultural crops implies increased total evapotranspiration and associated consumptive use of water (inherently related to the irrigation and water diversion and storage developments in the watershed). Thereby the runoff from the watershed into the lake has decreased, and the remaining smaller inflow to the lake has been insufficient for keeping up the previous lake WL, causing the observed WL drop to current conditions.
6.
Frampton, Andrew, et al.
(författare)
Transient modeling of permafrost dynamics in changing climate scenarios
2011
Konferensbidrag (refereegranskat) abstract
Analysis of permafrost dynamics with a three-phase, two-component flow system coupled to heat transport is used to evaluate transient changes in groundwater seepage. Both seasonal and annual analysis of flow is conducted, assuming three warming temperature trends over a ten year period, representing three climate change scenarios. Previous results have indicated that a reduction in temporal variability of groundwater flow is expected to occur for a moderate temperature trend over long warming time periods. Here, new results indicate this is also expected for larger rates-of-change of temperature increase and over shorter time periods. Additionally it is shown that short-term annual flow variability may serve as early indicators for permafrost degradation also for greater warming trends, rather than solely relying on long-term changes in mean flows.
7.
Jaramillo, Fernando, 1977-
(författare)
Changes in the Freshwater System : Distinguishing Climate and Landscape Drivers
2015
Doktorsavhandling (övrigt vetenskapligt/konstnärligt) abstract
Freshwater is a vital resource that circulates between the atmosphere, the land and the sea. Understanding and quantifying changes to the partitioning of precipitation into evapotranspiration, runoff and water storage change in the landscape are required for assessing changes to freshwater availability. However, the partitioning processes and their changes are complex due to multiple change drivers and effects. This thesis investigates and aims to identify and separate the effects of atmospheric climate change and various landscape drivers on long-term freshwater change. This is done based on hydroclimatic, land-use and water-use data from the beginning of the twentieth century up to present times and across different regions and scales, from catchment to global. The analyzed landscape drivers include historic developments of irrigated and non-irrigated agriculture and flow regulation. The thesis uses and develops further a data-motivated approach to interpret available hydroclimatic and landscape data for identification of water change drivers and effects, expanding the approach application from local to continental and global scales. Based on this approach development, the thesis identifies hydroclimatic change signals of landscape drivers against the background of multiple coexisting drivers influencing worldwide freshwater change, within and among hydrological basins. Globally, landscape drivers are needed to explain more than 70% of the historic hydroclimatic changes, of which a considerable proportion may be directly human-driven. These landscape- and human-driven water changes need to be considered and accounted for also in modeling and projection of changes to the freshwater system on land.
8.
Jaramillo, Fernando, 1977-, et al.
(författare)
Developing water change spectra and distinguishingchange drivers worldwide
2014
Ingår i: Geophysical Research Letters. - : American Geophysical Union (AGU). - 0094-8276 .- 1944-8007. ; 41:23, s. 8377-8386
Tidskriftsartikel (refereegranskat) abstract
The separate and combined effects of different drivers of change to water fluxes and resources onland (CWOL) remain difficult to distinguish and largely unknown, particularly at a global scale. Our studyanalyzes CWOL during the period 1901–2008, based on available hydroclimatic data for up to 859 hydrologicalbasins. We develop a worldwide spectrum of change magnitudes and directions in Budyko space, from whichwe distinguish climate and landscape drivers of CWOL. We find that landscape drivers (e.g., changes in landand water use, water storage or water phase) are needed to explain CWOL in at least 74% of the basins studied.The water change effects of such landscape drivers are mostly opposite to those of atmospheric climatechange. The change spectrum approach we developed provides a useful tool for quantifying and visualizingCWOL and for distinguishing the effects of climate and landscape drivers across regions and scales.
9.
Lindgren, Georg A., et al.
(författare)
Inland subsurface water system role for coastal nitrogen load dynamics and abatement responses
2007
Ingår i: Environmental Science & Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 41:7, s. 2159-2164
Tidskriftsartikel (refereegranskat) abstract
We simulate and analyze long-term dynamics of coastalnitrogen (N) loading and the inland source changes andprocesses that may have determined its development overthe past 60-year period and may govern its possiblefuture responses to variousNsource management scenarios.With regard to processes, the results show that averagebasin-scale N delivery fractions to the coast may not berepresentative of the coastal impacts of either diffuse orpoint inland sources. The effects of inland source changesmay be greatly redistributed in space-time and delayedby slow N transport and mass transfer processes in thesubsurface water system of coastal catchments. Extrapolationof current N transport-attenuation conditionsfor quantification of future abatement effects may thereforebe misleading if the extrapolation models do not realisticallyrepresent delayed long-term influences of slow subsurfaceprocesses. With regard to policy, the results show that andwhy national Swedish and international Baltic Searegion policies for coastal N load abatement may bedifficult or impossible to achieve by inland source abatementonly. Large mitigation of both point and diffuse sourcesmay be necessary to achieve targeted coastal N loadreductions fast and maintain them also in the long term.
10.
Mård Karlsson, Johanna, 1979-, et al.
(författare)
Opportunities and limitations to detect climate-related regime shifts in inland Arctic ecosystems through eco-hydrological monitoring
2011
Ingår i: Environmental Research Letters. - : IOP Publishing. - 1748-9326. ; 6:1, s. 014015-
Tidskriftsartikel (refereegranskat) abstract
This study has identified and mapped the occurrences of three different types of climate-driven and hydrologically mediated regime shifts in inland Arctic ecosystems: (i) from tundra to shrubland or forest, (ii) from terrestrial ecosystems to thermokarst lakes and wetlands, and (iii) from thermokarst lakes and wetlands to terrestrial ecosystems. The area coverage of these shifts is compared to that of hydrological and hydrochemical monitoring relevant to their possible detection. Hotspot areas are identified within the Yukon, Mackenzie, Barents/Norwegian Sea and Ob river basins, where systematic water monitoring overlaps with ecological monitoring and observed ecosystem regime shift occurrences, providing opportunities for linked eco-hydrological investigations that can improve our regime shift understanding, and detection and prediction capabilities. Overall, most of the total areal extent of shifts from tundra to shrubland and from terrestrial to aquatic regimes is in hydrologically and hydrochemically unmonitored areas. For shifts from aquatic to terrestrial regimes, related water and waterborne nitrogen and phosphorus fluxes are relatively well monitored, while waterborne carbon fluxes are unmonitored. There is a further large spatial mismatch between the coverage of hydrological and that of ecological monitoring, implying a need for more coordinated monitoring efforts to detect the waterborne mediation and propagation of changes and impacts associated with Arctic ecological regime shifts.
