Urban water system metabolism assessment using WaterMet2 model

12th International Conference on Computing and Control for the Water Industry, CCWI2013, 2013-09-06, 2013-09-09, Perugia, ItalyThis paper presents a new "WaterMet2" model for integrated modelling of an urban water system (UWS). The model is able to quantify the principal water flows and other main fluxes in the UWS. The UWS in WaterMet2 is characterised using four different spatial scales (indoor area, local area, subcatchment and system area) and a daily temporal resolution. The main subsystems in WaterMet2 include water supply, water demand, wastewater and cyclic water recovery. The WaterMet2 is demonstrated here through modelling of the urban water system of Oslo city in Norway. Given a fast population growth, WaterMet2 analyses a range of alternative intervention strategies including 'business as usual', addition of new water resources, increased rehabilitation rates and water demand schemes to improve the performance of the Oslo UWS. The resulting five intervention strategies were compared with respect to some major UWS performance profiles quantified by the WaterMet2 model and expert's opinions. The results demonstrate how an integrated modelling approach can assist planners in defining a better intervention strategy in the future.This work was carried out as part of the ‘TRansition to Urban water Services of Tomorrow’ (TRUST) project. The authors wish to acknowledge the European Commission for funding TRUST project in the 7th Framework Programme under Grant Agreement No. 265122

Dissecting the loci underlying maturation timing in Atlantic salmon using haplotype and multi-SNP based association methods

Characterizing the role of different mutational effect sizes in the evolution of fitness-related traits has been a major goal in evolutionary biology for a century. Such characterization in a diversity of systems, both model and non-model, will help to understand the genetic processes underlying fitness variation. However, well-characterized genetic architectures of such traits in wild populations remain uncommon. In this study, we used haplotype-based and multi-SNP Bayesian association methods with sequencing data for 313 individuals from wild populations to test the mutational composition of known candidate regions for sea age at maturation in Atlantic salmon (Salmo salar). We detected an association at five loci out of 116 candidates previously identified in an aquaculture strain with maturation timing in wild Atlantic salmon. We found that at four of these five loci, variation explained by the locus was predominantly driven by a single SNP suggesting the genetic architecture of this trait includes multiple loci with simple, non-clustered alleles and a locus with potentially more complex alleles. This highlights the diversity of genetic architectures that can exist for fitness-related traits. Furthermore, this study provides a useful multi-SNP framework for future work using sequencing data to characterize genetic variation underlying phenotypes in wild populations.Peer reviewe

Basin-scale phenology and effects of climate variability on global timing of initial seaward migration of Atlantic salmon (Salmo salar)

Migrations between different habitats are key events in the lives of many organisms. Such movements involve annually recurring travel over long distances usually triggered by seasonal changes in the environment. Often, the migration is associated with travel to or from reproduction areas to regions of growth. Young anadromous Atlantic salmon (Salmo salar) emigrate from freshwater nursery areas during spring and early summer to feed and grow in the North Atlantic Ocean. The transition from the freshwater (parr') stage to the migratory stage where they descend streams and enter salt water (smolt') is characterized by morphological, physiological and behavioural changes where the timing of this parr-smolt transition is cued by photoperiod and water temperature. Environmental conditions in the freshwater habitat control the downstream migration and contribute to within- and among-river variation in migratory timing. Moreover, the timing of the freshwater emigration has likely evolved to meet environmental conditions in the ocean as these affect growth and survival of the post-smolts. Using generalized additive mixed-effects modelling, we analysed spatio-temporal variations in the dates of downstream smolt migration in 67 rivers throughout the North Atlantic during the last five decades and found that migrations were earlier in populations in the east than the west. After accounting for this spatial effect, the initiation of the downstream migration among rivers was positively associated with freshwater temperatures, up to about 10 degrees C and levelling off at higher values, and with sea-surface temperatures. Earlier migration occurred when river discharge levels were low but increasing. On average, the initiation of the smolt seaward migration has occurred 2.5days earlier per decade throughout the basin of the North Atlantic. This shift in phenology matches changes in air, river, and ocean temperatures, suggesting that Atlantic salmon emigration is responding to the current global climate changes

Importance of investment decisions and rehabilitation approaches in an ageing wastewater pipeline network. A case study of Oslo (Norway)

As Oslo Vann og Avl\uf8psetaten (VAV, meaning Water and Sewage Department) looks into the future, it is faced with a quandary\u2014to replace old pipelines or to continue maintaining them. The primary goal is to improve the level of service. The secondary goals are to rejuvenate the system and stem the decline in capital value. In 1991\u20132006, the Operation and Maintenance expenses (O&M) were far higher than the investments, and the network aged as its capital value plummeted. However, if the funds are insufficient, the self-financing Oslo VAV would have to turn to the consumers for help. Will the consumers pay more to have a \u2018younger\u2019 system? What if they are happy with the \u2018status quo\u2019 and are unconcerned about the falling capital value? Should the pipelines be depreciated over a longer period than the 40 years which is adopted now? Should the economic method be replaced by a more engineering-based method, whereby the pipes are assessed \u2018on merit\u2019\u2014on the basis of their service lives? There are numerous issues and a good decision will ease the road ahead. This paper, using Life Cycle Costing Analysis (LCCA) and scenarios therein, looks at how Oslo VAV could strike a balance between expending on O&M, investing in upgrading the network, and decelerating the ageing of the network while augmenting the capital value, and what is the best attainable set of targets they could aim for, at the end of the next 20 years. The two approaches mentioned above are compared with each other. It is seen that a rehabilitation programme based on the pipes performance approach is preferable to one guided by an economic lifetime approach, when the motive is to optimise expenditure and also improve the level of service

CARE-S: computer Aided Rehabilitation of Sewer Networks, EU 5 Framework Program (contract EVK1-CT-2001-00167)

Today many wastewater networks suffer from insufficient capacity, construction failures and pipe deterioration. While the consequences are structural damage and local floods, the rationale behind rehabilitation decisions is often unclear. This is the background for a project in the 5th Framework Programme in EU, Computer Aided Rehabilitation of Sewers and Storm water networks (CARE-S). The project objective was to establish a broad rational framework for sewer network rehabilitation decision-making. The system CARE-S aims to improve the structural and functional reliability of the wastewater networks (risk of in- and exfiltration, collapse and blockage due to pipe deterioration, hydraulic overloading resulting in flooding and/or receiving water pollution), identifying optimal preventive maintenance strategies based on lifetime reliability and life-cycle costs. This is combined with the hydraulic analysis of the network capacity to take care of runoff from rainstorms and snow melt in urban areas, even upgrading the system if necessary. The ultimate product is a Decision Support System (DSS) that enables municipal engineers to establish and maintain effective management of their sewer networks. In other words: Rehabilitate the right sewer at the right time by using the right rehabilitation technique at a minimum total cost, before serious failures occur (pro-active approach). CARE-S supports utilities on planning preventive maintenance which, if it is not done, it will cost more at a later stage to keep the structure in a safe condition. The urban wastewater networks should be managed according to a three-tier approach: strategic, tactic and technologic level. The strategic level deals with long term planning, including long term goals, for example separation of networks, new design of pipelines to meet climate change effects, or computation of the severity of element deterioration, of which parts of the network is the most vulnerable and finally estimation of investment needs. CARE-S can support this by a comprehensive system for Performance Indicators, relying on data from network management system and general statistics. It also contains options for socioeconomic assessment, to find if the network causes over costs for customer. CARE-S is equipped with a tool for analysing and presenting the integrated need for rehabilitation over a long-term planning period. The tactical level deals with situation of each pipeline in network. A careful analysis of condition and probability of performance bottleneck is required, to understand which pipes are prone for upgrading. This may be a structural weakness or insufficient hydraulic capacity. CARE-S enables to import data from visual inspection of the buried pipes in order to analyse the real performance of the system in the current conditions. The topology of the network can be either imported with CCTV files, when the whole network has been inspected, with importing an Hydraulic model, or with importing the GIS-shape files. It is highly recommended to install a hydraulic model for the network. This can be used with data on installation and operation to calculate the hydraulic performance of existing network, when weaknesses due for deterioration are counted. Several structural weakness may occur, and CARE-S offers tools for several situations, being it clogging, roots, impact of leakages etc. The outcome of tactical analysis is a selection and ranking of rehabilitation candidates. The technical level comprises rehabilitation techniques to be applied once a project has been designed. For this purpose a comprehensive database has been developed, containing properties of renovation and repair techniques. Appropriate technology for each rehabilitation project is suggested and the utility’s engineers can choose techniques already applied by the municipality or can try and compute the effect of promoting new and advanced solutions