Fluids and Drainage Engineering - Essay Example

Download file to see previous pages... The most common use of engineering hydrology is the prediction of design events. This may be considered analogous to the estimation of design loads on structures. Design events do not mimic nature, but are merely a convenient way of designing safe and economical structures for water resources schemes. Civil engineers are principally concerned with the extremes of nature, design events may be either floods or droughts. The design of hydraulic structures will normally require the estimation of a suitable design flood and sometimes a design drought (Bedient and Huber, 1992). A large range of factors control the shape of hydrographs. These include: precipitation type and intensity, catchment shape, catchment gradient, land use and vegetation, soil type, geology etc. A hydrograph is the time-series record of water level, water flow or other hydraulic properties, and can be used to gain insights into the relationships between rivers and aquifers. Typically, a stream hydrograph shows the fluctuations in stream flow through time and is a commonly available dataset routinely measured to support the management of water resources. For a gaining stream, where groundwater is contributing to stream flow, analysis of the stream hydrograph can indicate the magnitude and timing of this contribution (Patra, 2001). Hydrographs are analyzed to find out discharge patterns of a particular drainage basin, Help predict flooding events, therefore influence implementation of flood prevention measures. Storm Hydrographs show the change in discharge caused by a period of rainfall. See Table 1 for the rainfall and river elevation data of River Thaw.
Table 1. Rainfall and river elevation data of River Thaw
Date
Time
Rainfall (mm)
Date
Time
River Level (m)
26.07.2007
00:00:00
0
26.07.2007
00:00:00
0.33
26.07.2007
01:00:00
0
26.07.2007
01:00:00
0.33
26.07.2007
02:00:00
0
26.07.2007
02:00:00
0.33
26.07.2007
03:00:00
0
26.07.2007
03:00:00
0.326
26.07.2007
04:00:00
0
26.07.2007
04:00:00
0.326
26.07.2007
05:00:00
0.2
26.07.2007
05:00:00
0.33
26.07.2007
06:00:00
0.6
26.07.2007
06:00:00
0.326
26.07.2007
07:00:00
4.2
26.07.2007
07:00:00
0.345
26.07.2007
08:00:00
6
26.07.2007
08:00:00
0.393
26.07.2007
09:00:00
3.4
26.07.2007
09:00:00
0.412
26.07.2007
10:00:00
2.4
26.07.2007
10:00:00
0.431
26.07.2007
11:00:00
3
26.07.2007
11:00:00
0.472
26.07.2007
12:00:00
3.2
26.07.2007
12:00:00
0.532
26.07.2007
13:00:00
2.4
26.07.2007
13:00:00
0.577
26.07.2007
14:00:00
0.2
26.07.2007
14:00:00
0.6
26.07.2007
15:00:00
0.2
26.07.2007
15:00:00
0.626
26.07.2007
16:00:00
0.2
26.07.2007
16:00:00
0.633
26.07.2007
17:00:00
0.2
26.07.2007
17:00:00
0.637
26.07.2007
18:00:00
0
26.07.2007
18:00:00
0.637
26.07.2007
19:00:00
0
26.07.2007
19:00:00
0.641
26.07.2007
20:00:00
0
26.07.2007
20:00:00
0.641
26.07.2007
21:00:00
0
26.07.2007
21:00:00
0.637
26.07.2007
22:00:00
0
26.07.2007
22:00:00
0.637
26.07.2007
23:00:00
0
26.07.2007
23:00:00
0.633

The flood hydrograph is basically a dual plot of river discharge as a line ...Download file to see next pagesRead More