Salinity intrusion is of growing concern in many regions where natural fresh water flows are impacted because of direct human activity such urbanization and dam construction, as well as climate change. Mathematical model of these natural systems can be efficiently used for estimating and evaluating the nature of the salinity intrusions on a seasonal and long-term basis.
Changing atmospheric temperatures affects water temperature and has adverse impact on a wide range of aquatic life. Simulation of the thermal regime coupled with forecast temperature scenarios helps regulators minimize the impacts of climate change and evaluate mitigation options.
Adapting to rising sea levels and mitigating the impacts of storm surges and associated flooding is a pressing need in coastal areas.
Salinity intrusion is of growing concern in many regions where natural fresh water flows are impacted because of direct human activity such as urbanization and dam construction, and sea-level rise due to climate change. Estimating and evaluating the nature of the salinity intrusions on a seasonal and multi-year basis is a complicated process for which numerical modeling can bring great benefits.
Instream habitat suitability studies are required for a wide variety of planning applications where aquatic organisms are an important consideration in the decision-making process. At certain flows, for example, the water may be too fast for juvenile fish or velocities may be too high for fish to spawn. At other flows, the water may be too shallow for spawning or suitable spawning gravel may not be covered by water.
Water temperature has significant and systematic effects on biological processes at all levels of organization, from phytoplankton to whole ecosystems. In addition to its own effects, temperature influences several other parameters and can alter the physical and chemical properties of water such as dissolved oxygen and photosynthesis production. Some organisms, particularly aquatic plants, flourish in warmer temperatures, while some fishes such as trout and salmon prefer colder streams.
Once-through Cooling Systems Thermoelectric power plants often make use of once-through cooling (OTC), a system whereby the water from nearby waterbodies is circulated through pipes to absorb heat from the steam in the condensers. The emission of this heated water back into the waterbody can have significant ecological impacts. For example EFDC+ has been used…
Stratified Lakes Large steep sided lakes with slow moving water are an example of where sharp thermoclines are often found in the summer months. The hypolimnion is often depleted of oxygen at this time due to the biological oxygen demand of bacterial decomposers. At depth there is also reduced photosynthetic activity. The density differences results…
Lake Washington is second largest natural lake in the State of Washington, USA. It is lake with steeply sloping sides and also has long-term, high quality vertical temperature records. This makes it an ideal case to test the Sigma-Zed layering approach. DSI developed a hydrodynamic model of this water body with 1,183 cells and 55 layers to assess the accuracy for prediction of the epilimnion and hypolimnion.
Lake Mead is the largest reservoir in the USA, and 16th largest man-made lake in the world. Lake Mead is formed by the Hoover Dam along the Colorado River. EFDC modeling studies have indicated that water level drawdown plays an important role in thermal stratification and water movement of Lake Mead during receding water levels (Li, 2010).