German version

German version

Hydraulic Modeling

As part of the European Union's Water Framework Directive, surface waters in all EU member states must, by 2015, be identified as having a good status. In order to realize this goal of improving most European water bodies, the knowledge of flow and transport processes is absolutely necessary. These processes are decisive in the development of rivers and watercourses. sje has extensive experience in the field of river hydraulics and hydraulic modeling. In addition to conventional tasks like water level calculations and the dimensioning of hydraulic installations, sje also employs 1D- and 2D-models to investigate flow behavior from low flow conditions to flood situations.

Ecohydraulics

Investigations concerning river ecology are ever more oriented toward quantitative information and alternative prognoses. The rudiments of ecohydraulics, like those implemented in the habitat models, conform to the idea that structural and hydraulic characteristics of the surface water must be directly linked to requirements to maintain water life. In doing so, the possibility presents itself that suitable habitat may be dependent on discharge, but also to predict different scenerios of watercourse development. Such predictions are of greatest use for both ecological and economic optimization of hydraulic engineering projects.

Renaturation

In recent years the water quality in most surface waters has improved considerably, but now morphological and hydraulic deficits more clearly manifest themselves, that is to say that the impairments from the interaction of flow and structure of the watercourse have become evident. Individual measures like the removal of control structures, the sites of flat water zones, the relocation of dikes, the connection of old waterways and so on are all sensible improvement measures.

To achieve long term improvement the highest aim must be to give back to rivers at least a part of their own dynamic. A river will unleash itself whenever possible, as if the running water liberates itself from a tight "corset." Steps in the direction of renaturation include: permitting some local erosion, tolerating shifting watercourses, and leaving some structural elements like deadwood in the water body.

Development of Watercourses

As mentioned above, to achieve a natural-like development of a watercourse, there has been the development, in recent times, of instruments for site-specific intervention. The aims of water resources management are formulated through the creation of water development concepts for rivers of higher order. These serve as the basis for the creation of water development plans, wherein precise provisions are worked out for both the natural environment and the necessary, accompanying development. sje provides services for the creation of water development concepts as well as water development plans.

Minimum Flow Studies

One of the most important questions arising from hydropower utilization at a power station along a diverted reach, and also identified from the estimated extraction, is the minimum flow. In such a situation, a part of the natural discharge remains in the main river channel, and on the one hand the ecological operability of the affected watercourse - the diverted reach - should be guaranteed. On the other hand, this water is passed through turbines in a hydropower plant, used as cooling water, or for irrigation purposes, and can no longer be recovered. These constraints may, particularly with small hydropower plants, jeopardize cost-effectiveness. Therefore the ecologically required minimum flow may be highly controversial.

Among the modern tools used by sje is a habitat simulation model, which can quantitatively establish the relationship between river habitat and discharge, and then depict the results. From such studies predetermined low flow conditions have been adapted to meet the requirements of the water life as they change seasonally, and these oftentimes provide ecological and economic advantages as opposed to regulations that are constant and specified.

Hydropower / Energy Concepts / Certification

Presently most energy production is based on primary energy carriers like coal, gas, and uranium. Beside the problem that the related production processes bring the greatest environmental strains (CO2-Problem, waste disposal, and so on), these energy carriers will decline in the coming decades. As a result the relevance of renewable energy sources, of which hydropower is quantitatively the most important, gains permanence. All the more important is not only an environmentally sound, but also an efficient hydropower utilization.

There exist numerous possibilities to enhance the efficiency and therefore the cost-effectiveness of either the conceptual design of new or the optimization of existing hydropower plants. This in turn provides a window of opportunity to improve the ecological operability of the affected watercourse. The close relationship between ecological and economical considerations of hydropower utilization is evident in that eco-power, as produced at an environmentally sound hydropower plant, can attain increased total revenues so that not only the owner, but also the environment benefit.

sje carries out studies on efficiency and calculates cost-effectiveness for hydropower plants. Additionally, the office is auditor for the certification of hydropower plants through the association for environmentally sound electricity (VUE, Schweiz), that is concerned presently with criterion for the allocation of the farthest reaching, environmentally sound eco-power-label, "naturemade star".

Hydraulic Engineering

Today one must bear in mind that the planning and implementation of hydraulic engineering projects are multidisciplinary. Already in the planning process with the combination of project aims, the water body itself and its related ecosystem should be sought to be impacted as little as possible. The conception of a hydraulic engineering installation, which must at the same time consider aspects like fish passes, natural flow regime, habitat in and at the water, and sediment budget, calls for technical and environmental competence. Thereby helping, at an early stage, to raise environmentally relevant questions that go beyond minimizing costs, but instead boost the acceptance of interventions on behalf of water bodies and oftentimes also speeding-up more positive official practices.

River Basin Management

In recent years it has become clear that to achieve sustainable improvements in running waters considerations at the local level are insufficient. Because rivers and their ecosystems are divided hierarchtically, measures, which are in line with long term goals, must therefore reach the higher levels of this hierarchy. In the framework of river basin management, running waters in their entirety are considered and the interrelationships and effects on the hydrosystem as a whole must be evaluated.

sje is a partner in a work group that, in the framework of the EU funded project RIVERTWIN, is working to develop an integrated model for such management. Included in the comprehensive assessment, and then later in the strategic planning, are different aspects such as land use, climate change, geological boundary conditions, sociological aspects, and the like.

Field Measurements

In order to execute water resources and hydraulic engineering projects, a foundation of reliable data must be gathered. Included herein are exact tachometric measurements, without which the application of novel tools like hydraulic models and simulation systems do not make sense. sje does its own on-site investigations with modern measuring equipment and carries out the related data evaluation and GIS-based data preparation.

Model Development

Numeric modeling becomes increasingly important for the investigation of extremely complex dependencies between water bodies and the ecosystems they support. To this aim, existing models have to be adapted to new scientific insights, but at the same time meeting the requirements of practical engineering applications.

sje cooperates with the Institute for Hydraulic Engineering at the University of Stuttgart and has been instrumental in the further development of the modeling system, CASiMiR, which is composed of different modules; for example, with one it is possible to assess habitat in running waters, with another the cost-effectiveness of hydropower plants. Through the cooperation of researchers in the European Aquatic Modelling Network (an EU sponsored exchange program), new developments in the modeling of hydrosystems are warranting the integration of state of the art in terms of systems modeling.