The numerous disciplines are responsible for the development and design of a hydroelectric facility development. The following explains their general areas of responsibility in the design team:
The Hydropower Engineer is a generalist who is familiar with the whole scope of hydropower development and is able to assist Owners in assessing the probable potential of a site for installation of a hydroelectric or pumped storage project, guide the process of selecting consultants for prefeasibility studies, feasibility studies, definitive design and estimation, construction contract preparation, tendering and award, site supervision and commissioning.
A site for hydroelectric development is often selected in the first instance by geospacial analysis. Programs such as Global Mapper or ARC GIS can be used to download satellite topography for an area as a digital terraine model (DTM) or digital elevation model (DEM), locate sites that look promising, map reservoir areas for various possible full supply elevations, check otehr data sets to investigate the locations of parks, land ownership, etc. that might affect the project, and even obtain first estimates of dam volumes.
The primary expert on catchments is the hydrologist who is responsible for developing the key data on which the design of the hydro facility is based, such as:
- Rainfall intensity versus month of the year, duration and probability, which is primarily used for the design of roof drainage and site drainage;
- Flood discharge versus probability, which is used to find how large the spillway and diversion works need to be;
- The Maximum Probably Flood, which is used to determine the size of the spill release facilities for dams with a High or Extreme consequence classification;
- Daily or monthly inflow sequences for the reservoir, which is normally based on records from flow gauging stations on the same river or nearby rivers, with appropriate adjustments for catchment size, elevation and rainfall pattern; and
- The shape of the Flood hydrograph, which shows how the reservoir inflow will rise after a major storm in the catchment, and how quickly it will fall after the rain stops.
The Hydrotechnical Engineer
University courses for Hydrotechnical engineers include hydrology, so they sometime perform the above calculations. However, they usually receive the results from the hydrologist and then produce design inputs such as the following:
- design flows for roof drains and culverts based on the rainfall intensity data;
- design discharges for the diversion works, based on the flood frequency data;
- reservoir routing calculations to determine the resulting reservoir outflows, based on the flood frequency data, probable maximum flood and the inflow hydrograph;
- dam break calculations to determing the discharge hydrograph from the reservoir in the event of a dam breach;
- inundation mapping to determine the timing and extent of downstream flooding for both normal floods and a dam breach event;
- the Incremental Consequence Category of the dam (the consequences that would result with the dam in place versus the consequence if no dam were built) based on the consequence of the mapped inundation;
- the design flood for the dam based on the Incremental Consequence Category;
- the flow-duration curve, which shows the relationship between reservoir inflows and probability of occurrence, from the inflow sequences.