Several studies have reported agronomic benefits by improving soil health/quality, but uncertain knowledge remains when determining specific impacts on water quality off-field. This study investigated the links between runoff water quality and soil health/quality in agricultural fields of the Mississippi delta under three land management scenarios: Conservation Reserve Program (CRP), vegetative buffer (VB), and row crops (RC). Using the Soil Management Assessment Framework (SMAF), a Soil Quality Index (SQI) was obtained based on ten soil health/quality indicators from 2008 and 2012 datasets. The SMAF identified significant differences in soil health/quality improvements among scenarios over a four-year period. Varied relationships between water quality parameters, SQI, and soil health/quality indicators were determined. Individually, physical and chemical soil indicators were also correlated with runoff water quality. Overall, the evidenced relationship between soil health/quality and water quality parameters was stronger in areas under CRP.

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Many Best Management Practices (BMPs) have been developed to reduce excessive nutrients in stormwater runoff and mitigate harmful algal blooms in downstream receiving water bodies. This study demonstrates a new BMP by comparing two green sorption media (i.e., specialty adsorbents) for nutrient removal in cascade upflow biofiltration systems operated in parallel. The proposed filtration technology can control hydraulic gradients, prevent clogging and settlements, and increase hydraulic loading while removing more nutrients in an integrated physicochemical and microbiological treatment process. The two green sorption media being tested in this study include zero-valent-iron and perlite-based green sorption media (ZIPGEM) and biochar, iron, and perlite-integrated green sorption media (BIPGEM). BIPGEM or ZIPGEM was installed in two identical upflow bioreactors operated in sequence within each biofiltration system compared mainly for nitrate removal at three influent conditions for process reliability assessment. In addition, kinetics studies were conducted and analyzed to improve the understanding of reactor design. Dissolved organic nitrogen was monitored by using FT-ICR MS (Fourier transform ion cyclotron resonance mass spectrometer) whereas population dynamics of nitrifiers and denitrifiers were quantified by using RT-PCR (real time polymerase chain reaction). The process reliability was compared and confirmed based on the nitrate removal efficiencies, microbial population, and oxidation-reduction potential variations across the two biofiltration systems with different green sorption media. Results indicated that ZIPGEM performed slightly better than BIPGEM and the two identical upflow bioreactors operated in sequence within each biofiltration system exhibited steady operation with higher hydraulic loading relative to the downflow settings in the literature.

Salar de Atacama (SdA) located in Northern Chile is home to one of the planet’s largest salar systems and lithium resources. Managing groundwater resources in salars is not obvious due to the lack of scientific understanding on the connectivity between the freshwater and brine systems. Using heat as a tracer in SdA provides a cost-effective method to further investigate groundwater flow in salars. This study employs 372 temperature-depth profiles from 90 boreholes between 2013-18 to understand the distinct thermal zones and flow between them in SdA. Three thermal zones exist within the southern margin of SdA’s thermal regime, at higher elevations alluvial fans containing freshwater have a temperature range between 23-28 °C. Down-gradient 2.5 km into the salar transition zone, characterized by freshwater lagoons and newly formed carbonates, the temperature range decreases to 12-17 °C. The transition zone, adjacent to the mature halite crust which hosts a lithium bearing brine and ranges in temperature from 18-22 °C. A 2D numerical groundwater and heat flow model was created to test three hydrologic scenarios to determine how the currently observed thermal regime exists and what the role of groundwater flow is between the different thermal zones. Results demonstrate that a focused flow concept matches current thermal observations with warm inflowing water discharging into the transition zone, cooling due to evaporation, reinfiltrating and preferentially flowing near the surface and discharging again at lagoons near the halite nucleus. Initial focused flow models had the halite nucleus and transition zone hydraulically connected, but results displayed advective flow between the two zones and the halite nucleus carried too much heat from current observations. Indicating the halite nucleus and transition zone has minimal connection, otherwise advective flow would result in thermal equilibrium and a lack of distinct zones as observed. Proper interpretation of temperature-depth profiles along with 2D models place critical constraints on the connectivity between the brine and freshwater systems, providing insight into salar surface energy budgets and a more comprehensive understanding of groundwater flow in the southern margin of SdA. This work gives a new perspective on the groundwater system in SdA while also contributing a novel case study to using heat as a tracer in salar systems.

Norrvatten producerar dricksvatten i sitt vattenverk, Görvälnverket, som distribueras till 700 000 människor i norra Stockholm. Om problem uppstår med den ordinarie dricksvattenförsörjningen kan leveranserna säkras upp genom en reservvattenförsörjning. Norrvattens nuvarande reservvattenförsörjning klarar dock inte av att leverera tillräcklig kapacitet och kvalitet totalt sett och behöver därför förstärkas. För att utgöra underlag för vidarearbete med att förstärka Norrvattens reservvattenförsörjning genomförs en multikriterieanalys där sju olika reservvattenalternativ analyseras med avseende på ett antal kriterier. MKA-verktyget Water Investments for Sustainability Enhancement and Reliability (WISER) tillämpas som är utvecklat för att studera dricksvattenåtgärder. Även fyra olika känslighetsanalyser utförs för att se hur resultatet påverkas av val av viktning och hur osäkerheter i använd data bidrar till osäkerheten i resultatet.  Resultatet visade att alla reservvattenalternativ förutom ett är fördelaktiga jämfört med Norrvattens nuvarande reservvattenförsörjning. Det vore mest fördelaktigt att etablera en ny grundvattentäkt eller förstärka de befintliga grundvattentäkterna. Etablering av ett nytt råvattenintag till Görvälnverket bedöms ofördelaktigt jämfört med de andra alternativen. Om Norrvatten inte skulle begränsas av ekonomiska tillgångar visar resultatet istället att alla alternativ är fördelaktiga och rangordningen av alternativen ändras. Rangordning ändras även om analysen enbart beaktar alternativens kapacitet och dricksvattenkvalitet. För att uppnå Norrvattens målproduktion av reservvatten behöver fler av alternativen etableras, eller bara ett nytt råvattenintag till Görvälnverket. De kriterier som bidrar med störst osäkerhet i resultatet är investeringskostnader samt drift- och underhållskostnader följt av genomförbarhet, rådighet och dricksvattenkvalitet. Resultatet påverkas mer av osäkerheterna i kriterierna investeringskostnader, drift- och underhållskostnader, dricksvattenkvalitet och tillförlitlighet än de övriga kriterierna. / Norrvatten produces drinking water in its Water Treatment Plant, Görvälnverket, which is distributed to 700,000 people in northern Stockholm. If problems arise with the ordinary drinking water supply, the deliveries can be secured through a reserve water supply. However, Norrvatten's current reserve water supply is not able to deliver sufficient capacity and quality overall and therefore needs to be strengthened. To form a basis for further work to strengthen Norrvatten's reserve water supply, a Multi Criteria Analysis is carried out in which seven different reserve water alternatives are evaluated regarding several criteria. The MCA tool Water Investments for Sustainability Enhancement and Reliability (WISER) is applied, which has been developed to study drinking water measures. Four different sensitivity analyzes are also performed to see how the result is affected by the choice of weighting and how uncertainties in the data used contribute to the uncertainty in the result.  The result showed that all reserve water alternatives except one are favorable compared with Norrvatten's current reserve water supply. It would be most favorable to establish a new groundwater source or to strengthen the existing groundwater sources. Establishment of a new raw water intake to Görvälnverket is considered unfavorable compared with the other alternatives. If Norrvatten wouldn’t be limited by financial assets, the result instead show that all alternatives are favorable and the ranking of the alternatives changes. The ranking of the alternatives also changes if the analysis only considers the alternatives' capacity and drinking water quality. To achieve Norrvatten's goal production of reserve water, several of the alternatives need to be established, or only a new raw water intake to Görvälnverket. The criteria that contribute to the greatest uncertainty in the result are investment costs as well as operating and maintenance costs followed by feasibility, availability and drinking water quality. The result is affected more by the criteria investment costs, operating and maintenance costs, drinking water quality and reliability than the other criteria.

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