The maximum upward flux (Eₘₐₓ) is a control condition for the development of groundwater evaporation models, which can be predicted through the Gardner model. A high-precision Eₘₐₓ prediction helps to improve irrigation practice. When using the Gardner model, it has widely been accepted to ignore parameter b (a soil-water constant) for model simplification. However, this may affect the prediction accuracy; therefore, how parameter b affects Eₘₐₓ requires detailed investigation. An indoor one-dimensional soil-column evaporation experiment was conducted to observe Eₘₐₓ in the presence of a water table of depth 50 cm. The study consisted of 13 treatments based on four solutes and three concentrations in groundwater: KCl, NaCl, CaCl₂, and MgCl₂, with concentrations of 5, 30, and 100 g/L (salty groundwater); distilled water was used as a control treatment. Results indicated that for the experimental homogeneous loam, the average Eₘₐₓ for the treatments supplied by salty groundwater was larger than that supplied by distilled water. Furthermore, during the prediction of the Gardner-model-based Eₘₐₓ, ignoring b and including b always led to an overestimate and underestimate, respectively, compared to the observed Eₘₐₓ. However, the maximum upward flux calculated including b (i.e. Ebₘₐₓ) had higher accuracy than that ignoring b for Eₘₐₓ prediction. Moreover, the impact of ignoring b on Eₘₐₓ gradually weakened with increasing b value. This research helps to reveal the groundwater evaporation mechanism.

An accurate estimate of the groundwater inflow to a tunnel is one of the most challenging but essential tasks in tunnel design and construction. Most of the numerical or analytical solutions that have been developed ignore tunnel seepage conditions, material properties and hydraulic-head changes along the tunnel route during the excavation process, leading to inaccurate prediction of inflow rates. A method is introduced that uses MODFLOW code of GMS software to predict inflow rate as the tunnel boring machine (TBM) gradually advances. In this method, the tunnel boundary condition is conceptualized and defined using Drain package, which is simulated by dividing the drilling process into a series of successive intervals based on the tunnel excavation rates. In addition, the drain elevations are specified as the respective tunnel elevations, and the conductance parameters are assigned to intervals, depending on the TBM type and the tunnel seepage condition. The Qomroud water conveyance tunnel, located in Lorestan province of Iran, is 36 km in length. Since the Qomroud tunnel involved groundwater inrush during excavating, it is considered as a good case study to evaluate the presented method. The groundwater inflow to this tunnel during the TBM advance is simulated using the proposed method and the predicted rates are compared with observed rates. The results show that the presented method can satisfactorily predict the inflow rates as the TBM advances.

With depleted coal resources or deteriorating mining geological conditions, some coal mines have been abandoned in the Fengfeng mining district, China. Water that accumulates in an abandoned underground mine (goaf water) may be a hazard to neighboring mines and impact the groundwater environment. Groundwater samples at three abandoned mines (Yi, Er and Quantou mines) in the Fengfeng mining district and the underlying Ordovician limestone aquifer were collected to characterize their chemical and isotopic compositions and identify the sources of the mine water. The water was HCO₃·SO₄-Ca·Mg type in Er mine and the auxiliary shaft of Yi mine, and HCO₃·SO₄-Na type in the main shaft of Quantou mine. The isotopic compositions (δD and δ¹⁸O) of water in the three abandoned mines were close to that of Ordovician limestone groundwater. Faults in the abandoned mines were developmental, possibly facilitating inflows of groundwater from the underlying Ordovician limestone aquifers into the coal mines. Although the Sr²⁺ concentrations differed considerably, the ratios of Sr²⁺/Ca²⁺ and ⁸⁷Sr/⁸⁶Sr and the ³⁴S content of SO₄²⁻ were similar for all three mine waters and Ordovician limestone groundwater, indicating that a close hydraulic connection may exist. Geochemical and isotopic indicators suggest that (1) the mine waters may originate mainly from the Ordovician limestone groundwater inflows, and (2) the upward hydraulic gradient in the limestone aquifer may prevent its contamination by the overlying abandoned mine water. The results of this study could be useful for water resources management in this area and other similar mining areas.

The hydrodynamic processes and impacts exerted by river–groundwater transformation need to be studied at regional and catchment scale, especially with respect to diverse geology and lithology. This work adopted an integrated method to study four typical modes (characterized primarily by lithology, flow subsystems, and gaining/losing river status) and the associated hydrodynamic processes and ecological impacts in the southern part of Junggar Basin, China. River–groundwater transformation occurs one to four times along the basin route. For mode classification, such transformation occurs: once or twice, controlled by lithological factors (mode 1); twice, impacted by geomorphic features and lithological structures (mode 2); and three or four times, controlled by both geological and lithological structures (modes 3 and 4). Results also suggest: (1) there exist local and regional groundwater flow subsystems at ~400 m depth, which form a multistage nested groundwater flow system. The groundwater flow velocities are 0.1–1.0 and <0.1 m/day for each of two subsystems; (2) the primary groundwater hydro-chemical type takes on apparent horizontal and vertical zoning characteristics, and the TDS of the groundwater evidently increases along the direction of groundwater flow, driven by hydrodynamic processes; (3) the streams, wetland and terminal lakes are the end-points of the local and regional groundwater flow systems. This work indicates that not only are groundwater and river water derived from the same source, but also hydrodynamic and hydro-chemical processes and ecological effects, as a whole in arid areas, are controlled by stream–groundwater transformation.

The production of tilapia (Oreochromis niloticus) in cages requires the constant monitoring of the physical and chemical water properties, since it is an activity considered potentially polluting for the aquatic environment and its monitoring is fundamental to avoid the water body eutrophication processes. The present study was conducted in a reservoir located in a fishfarm at Pariquera – Açu County (São Paulo state, Brazil) and evaluated the influence of the intensive Nile tilapia production in cages on the trophic state and in the water quality. For the trophic state determination, five classes were considered and stablished by the Trophic State Index (TSI). The trial was developed and divided in three phases: before (90 days), during (180 days) and after (90 days) the fish intensive production in the reservoir. Thirty net cages with volume of 4 m3 and stocking density of 150 fish per m3 were installed. According to the results, it was observed that the trophic state index (TSI) was increasing according to the production period, changing from an ultra-oligotrophic to a mesotrophic state, reaching a maximum value of 53.2 ± 0.4, and, after production period, remained oligotrophic. The water quality parameters did not present significant differences between the periods analysed (p>0.05). The implementation of the TSI represents a practical tool for environmental monitoring and risk analysis of fish production in the aquatic environment. | A produção de tilápias (Oreochromis niloticus) em tanques-rede exige o constante monitoramento das propriedades físico-químicas da água, pois é uma atividade considerada potencialmente poluidora do ambiente aquático e o monitoramento é fundamental para evitar processos de eutrofização do corpo hídrico. O presente estudo avaliou a influência da produção intensiva de tilápia do Nilo em tanques-rede sobre o grau de trofia e qualidade da água em uma represa localizada no Vale do Ribeira, região de Mata Atlântica no sudeste do Brasil. Na classificação do grau de trofia foram considerados cinco classes, que foram estabelecidas a partir do Índice do Estado Trófico (IET). O experimento foi conduzido em três períodos: antes (90 dias), durante (180 dias) e após (90 dias) à produção intensiva de peixes na represa. Instalaram-se 30 tanques-rede de 4 m3 com densidade de estocagem de 150 peixes por m3. A partir dos resultados experimentais, verificou-se que o IET foi crescente no período de produção passando de ultraoligotrófico à mesotrófico, alcançou valor máximo de 53,2 ± 0,4 e após a produção manteve-se oligotrófico. Os parâmetros de qualidade de água não apresentaram diferenças significativas entre os períodos analisados (p>0.05). A aplicação com base no IET representa uma ferramenta prática para o monitoramento ambiental e análise de riscos da produção de peixes no ambiente aquático.

Methods that use diurnal groundwater-level fluctuations are commonly used for shallow water-table environments to estimate evapotranspiration (ET) and recharge. The key element needed to obtain reliable estimates is the specific yield (Sy), a soil-water storage parameter that depends on unsaturated soil-moisture and water-table fluxes, among others. Soil-moisture profile measurement down to the water table, along with water-table-depth measurements, can provide a good opportunity to calculate Sy values even on a sub-daily scale. These values were compared with Sy estimates derived by traditional techniques, and it was found that slug-test-based Sy values gave the most similar results in a sandy soil environment. Therefore, slug-test methods, which are relatively cheap and require little time, were most suited to estimate Sy using diurnal fluctuations. The reason for this is that the timeframe of the slug-test measurement is very similar to the dynamic of the diurnal signal. The dynamic characteristic of Sy was also analyzed on a sub-daily scale (depending mostly on the speed of drainage from the soil profile) and a remarkable difference was found in Sy with respect to the rate of change of the water table. When comparing constant and sub-daily (dynamic) Sy values for ET estimation, the sub-daily Sy application yielded higher correlation, but only a slightly smaller deviation from the control ET method, compared with the usage of constant Sy.

"Se evaluó el efecto de las enzimas de vísceras de sardi¬na Monterey en el tratamiento del agua de cola producida por sardinas crinuda y Monterey y, se compararon con enzimas de un extracto comercial. Además, se aplicó una centrifugación complementaria al ensayo. La enzima comercial tuvo mayor actividad proteasa que la enzima de víscera de sardina (0.65 U/mg vs. 0.35 U/mg) y que la actividad colagenasa (0.022 Hyp/mg/min vs. 0.0102 Hyp/mg/min). Se observaron grados de hidrolisis mayores sobre agua de cola de sardina crinuda (16.1 %), y no se registraron diferencias significativas (P≥0.05) en el agua de cola de sardina Monterey por el uso de las en¬zimas de vísceras de sardina Monterey y enzimas comercial. Se obtuvo mayor hidrolisis al aplicar la enzima de víscera de sardina Monterey sobre el agua de cola centrifugada (57.1 % vs. 17.4 %) sin importar la especie de sardina utilizada. La enzima comercial disminuyó la viscosidad sobre el agua de cola, mientras que la enzima de víscera de sardina Monterey lo hizo sobre el agua de cola centrifugada. La electroforesis mostró una disminución de la fracción PM>220 kDa en el agua de cola. Lo anterior, indicó que la enzima comercial tuvo una mayor actividad sobre agua de cola, mientras que la enzima de víscera de sardina Monterey lo tuvo en agua de cola centrifugada, sin importar el tipo de sardina utilizada para la elaboración del agua de cola." | "We evaluated the effect of Monterey sardines viscera enzyme on stickwater treatment produced by crinude and Monterey sardines and compared with commercial enzyme. In addition, we applied a complementary centrifugation to add in test. Commercial enzyme has greater protease activity than Monterey sardines viscera (0.65 U/mg vs. 0.35 U/mg) and collagenase activity (0.022 Hyp/mg/min vs. 0.0102 Hyp/mg/ min). Higher degree of hydrolysis on stickwater from crinude sardine (16.1 %), and no significant differences (P≥0.05) on stickwater from Monterey sardine between commercial en¬zyme and Monterey sardine viscera were observed. Degree of hydrolysis increased to application Monterey sardines vis¬cera on centrifuged stickwater (57.1 % vs. 17.4 %) regardless of which sardine specie it came from. Commercial enzyme reduced viscosity on stickwater while Monterey sardines viscera did it on centrifuged stickwater. The electrophoresis showed reduction on MW>220 kDa fraction in stickwater. The above, showed that commercial enzyme have a better activity on stickwater while Monterey sardines viscera did it better on the centrifuged stickwater, regardless sardine specie which the stickwater came from."

El Comando de Ingenieros (COING) del Ejército Nacional de Colombia, adelanta estudios para realizar una adecuación de la planta de tratamiento de agua residual del Puesto de Mando Adelantado (PMAD) Los Mangos, ubicado en el Fuerte Militar de Tolemaida. La sugerencia del COING se centra en la construcción de una laguna de oxidación que pueda eliminar de forma natural los patógenos y materia orgánica provenientes de las actividades domésticas del batallón. Actualmente el Batallón de Apoyo de Servicios para la Educación Militar (BASEM) es el encargado de llevar un seguimiento a las actividades realizadas en el PMAD. Los Mangos, no obstante, dicha unidad militar no cuenta con soportes técnicos de las dimensiones de la laguna de oxidación propuesta por el COING, de manera que, se realiza una evaluación con base a criterios establecidos por el Centro Panamericano de Ingeniería Sanitaria y Ciencias del Ambiente (CEPIS), para garantizar viabilidad, control y funcionalidad de la misma. Según los parámetros fisicoquímicos que favorecen el proceso y las características propias del diseño, se determina que es una laguna facultativa, por lo tanto, su periodo de retención debe estar dentro del rango de 5 a 30 días, sin embargo, al evaluar éste parámetro fundamental para la eficiencia de la laguna, se estimó un tiempo de 2.71 días. Para cumplir con éste criterio, se recomienda que la profundidad no sea de 1.5 m sino de 2.5 m, teniendo en cuenta que el tiempo de retención hidráulico depende principalmente de la forma, tamaño y del flujo disperso en la laguna. De ésta manera se obtendrán remociones eficientes tanto de coliformes fecales como de DBO. Para obtener resultados favorables en el tratamiento de las aguas residuales, además de contar con un diseño óptimo, es indispensable realizar mantenimiento periódico a la laguna de oxidación, y así evitar problemas como eutrofización, estancamientos, rupturas de membrana y vectores. | The COING [Comando de Ingenieros del Ejército Nacional de Colombia] advance in researches to adecuate the residual water treatment plant of the PMAD [Puesto de mando adelantado] Los Mangos located in the military base (Tolemaida-Colombia). The COING suggestion is focused in the construction of an oxidation pond that can eliminate in natural form pathogens and organic material originated from the domestic activities of the military base. The BASEM [Batallón de Apoyo de Servicios para la Educación Militar] is the responsible now to follow the activities realized in the PMAD los Mangos, nevertheless, this military unit does not have enough technical information about the oxidation pond dimensions proposed by the COING; that is why an evaluation is realized according with the criteria established by the CEPIS [Centro Panamericano de Ingeniería Sanitaria y Ciencias del Ambiente], to guarantee viability, control and functionality of the oxidation pond. According with the physically and chemical parameters who assist the process and the characteristics of the design, was determined it is a facultative pond; it needs an hydraulic retention time standard into the range of 5 to 30 days however at the moment of the evaluation the results showed 2.71 days. To achieve with this criteria it is recommended to change the depth from 1.5 to 2.5 meters, having in mind that the hydraulic retention time depends on the form, size and liquid dispersed into the pond. Working with this changes will be obtained efficient removal processes in thermotolerant (fecal) coliforms and Biological Oxygen Demand (BOD). To obtain better results in the residual water treatment it is necessary to have an optimal design and work periodically in the oxidation pond maintenance, to avoid problems like water eutrophication, blockages, membrane structure rupture and vectors. | Ejército Nacional de Colombia