Environmental carrying capacity for sustainable shrimp farming.

Aquaculture, particularly shrimp farming in the Kandaleru creek area, has shown spectacular growth within the last two decades. However, economic prosperity which was the driving force for shrimp farming expansion, has also had a significant negative impact on land use changes and creek water quality causing shrimp health hazards. Using a hypothesis that the discharge of shrimp farming effluents may have exceeded the carrying capacity (CC) of the creek water, the environmental CC of Kandaleru creek was assessed based on total nitrogen (TN) input. Remote sensing (RS) and image enhancement techniques integrated with geographical information systems (GIS) were applied to quantify and determine the changes in land use patterns in the creek area. GIS and a numeric model were used to compute the TN load in three different salinity zones to determine the CC status. The study revealed that exceeding the CC of the creek along with increasing shrimp farms, decreasing natural resources and changes in land use patterns.

Long-term natural flow regime (spells) analysis for water treatment discharges

Conducting mineral extraction activities usually requires obtaining a set of permits for each of the activities planned to be undertaken. This directly concerns water management and discharges associated with any mineral extraction operations. In response to the growing demand for energy resources worldwide, the industry demand for permits relating to the extraction of coal seam (and shale) gas also increased dramatically. This was in turn accompanied by the growing community concerns in regard to fracking and wastewater management practices. To address these concerns, the state governments in Australia developed a strict framework and guidelines for the permit application process and provided terms of reference for the environmental impact assessments, where required. In accord with the guidelines, a liquefied natural gas mining operator was conducting a research to assess several facets of water releases from Reedy Creek Water Treatment Facility to Yuleba Creek in Queensland. The scope for the research was developed in line with such guidelines and included estimating the downstream extents of flows from several Water Treatment Facility discharge volumes over a period of planned discharges. More specifically, the purpose of the study presented in this paper was to assess flows in Yuleba Creek before and after the proposed releases of treated water from the Reedy Creek Water Treatment Facility, and how the planned change to flow parameters would satisfy the regulatory guidelines. The assessment was based on 41 years of data collected at the Forestry Station gauge. An analysis of the obtained results suggested that the historical maximum was 25,825 ML/d. An analysis of the median flows suggested that the years 1983, 1999, and 2010-2012 had the highest medians of around 15 ML/d, 10 ML/d, and from 9 ML/d to 12 ML/d respectively. The median flow values would exceed from 0.09 ML/d to 0.69 ML/d flows during the months of February and March only. The lowest 90th percentile flows were obtained for the months from April through to October. The highest flow estimates would be in the months from November through to March. An analysis of the flow duration curves suggested that the annually averaged flow of 0.08 ML/d in the Yuleba Creek would be present for around 48% of the time. Flows predictabilities were calculated; for the baseline flow records, the value of predictability was 0.50, and the constancy/predictability ratio was 0.89. The rates of streamflow rise and fall were estimated and analysed. The results suggested that the rate of streamflow rise varied within a range from 0.0 up to 320.0 ML/d per day. The rates of streamflow fall was up to 15.0 ML/d per day.

Thorium and Uranium distribution in a passive system for mine water treatment

The abandoned Jales mining area is a sulphide-rich deposit (Northeast of Portugal). Acid mine drainage resulted from oxidation of sulphides is treated in a passive system with wetlands. The present work studies the thorium and uranium behaviour in the water and in the fine fractions of wetland soils throughout the passive treatment system. The evaluation of the efficiency of the all system was done determining metals concentration variation in the creek water upstream and downstream of the treated effluent discharge. The results point to higher efficiency to retain Th after summer than after winter. The opposite was found for uranium, which increases significantly in the creek water after summer and, in a lower extent, after winter. Also, Th and U have a tendency to increase in the fine fractions of the wetlands soils after summer, which can be explained by the longer water-soil contact/lower water dynamics. Nevertheless uranium has a much higher tendency to be in solution as revealed by a high concentration in the porewater of wetland soils. A relation of these actinides behaviour with the Fe and Mn distribution is not clear.

Sırakaraağaçlar Deresinde (Sinop-Karadeniz Bölgesi) Anyonik Deterjan Kirliliğinin Araştırılması

The study was carried out between May 2014 and April 2015 with the aim of determining the anionic detergent pollution and some physico-chemical properties PH, temperature, conductivity, salinity, dissolved oxygen (DO), total hardness (TH), chemical oxygen demand (COD), PO4-3-P, total nitrogen (TN)] of the Sırakaraağaçlar creek in Sinop. According to the results of one year measurement, it was established that the minimum and maximum values of the anionic detergent concentration vary between 0.02 and 0.98 mg/l, respectively. The results were classified according to Turkey’s Water Quality Management Regulation criteria (2008 and 2016). Sırakaraağaç creek water has been determined high quality water and slightly dirty water (class I and II) acording to the pH, temperature and phosphorus concentrations. It was found to be high quality water in terms of total nitrogen and COD parameters. Additionally, creek water is equivalent to polluted water (class II and III) according to anionic detergent concentration and DO values. High anionic detergent and low oxygen content can pose a hazard to sensitive aquatic organisms. Thus, the creek is especially under pressure in terms of anionic detergent and DO. Results of this study showed that the sources of pollution threatening the creek may be primarily the environmental factors that include human and agricultural activities.

Strengthening of a railway arch bridge from 1854

This paper presents the inspection of the condition and the design for strengthening of an existing railway arch bridge constructed in 1854. The original arch bridge is constructed with 5 layers of bricks in the arch and granite blocks in the foundation on top of an arrangement of frame made of timber and carried by piles. From the inspection it was concluded that the bricks in the arch was damaged due to freeze-thaw. It was also concluded that the timber structure in the foundation was rotten. The bridge is crossing a small creek. The environment is very sensitive. The access to the construction site is passing through landscape subject to preservation. The strengthening project included the arrangement of a new reinforced concrete arch. The arch was anchored with glued reinforcement bonded to the existing brick arch. The reinforcement and formwork was placed above the creek without disturbing the fauna in the water. The concrete was pumped into a form under the existing arch. After curing of the concrete arch, the strengthening of the foundation was initiated. It was planned to construct a bottom slab under the creek, which was able to carry the new concrete arch. In order to get access for the construction work the creek water was pumped through pipes suspended under the top of the new concrete arch. The procedures to handle the very delicate situation of replacing the foundation, while the bridge was in operation, and also protecting the environment is described in detail in the presentation. The process included high speed concrete curing, working processes under extreme narrow conditions and a very tight schedule.