Cu07821 ppt9 recapitulation
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Transcript of Cu07821 ppt9 recapitulation
Goal Course Watermanagement
• Knowledge of the working of the water system, how it works, what has an influence on what, what are you aiming at, which processes take place
• Policy
Goals
• Optimal circumstances for farmers and nature, optimal water table and gain
• Prevention of water trouble, fulfill on the rainfall event NBW, 1:25 year shower, Stowa
• Prevention of water shortage? No guidelines exist, even for a dry period, maintain the water level?
• Water framework directive, European directive, ecological quality. Is about the quality of the water system itself.
• Prevention of salination?
Model Sobek
• Area 1 500 hagsl +0,8 mDepth drainage 1 mSummer level (weir) -0,3 m , freeboard 1,1 m
• Area 2 500 hagsl +0,1 mDepth drainage 0,7 mSummer level (pump) -0,7 m , freeboard 0,8 m
• Infiltration 99 mm/hour !!• Depression 5 mm• μ=0,060 storage in soil• Drainage De Zeeuw Hellinga• No seepage• Pump 11 mm/day = 1,27 m3/s • Precipitation 96 hour 100mm, 4 days• Calculated steps 5 min, for 1 month
Questions
• What is the percentage surface water?• Surface water max 11,2 ha = 1,1 %• μ=0,060 storage soil• How much m3 of water can be stored in a
layer of 10 cm soil, in an area of 1000 ha.• 1000 x 10.000 x 0,1 x 0,06 = 60.000 m3• What is the amount of precipitation in m3?• 1000 x 10.000 x 100/1000 = 1.000.000 m3• How much water will be discharged (max)?• 11/1000 x 4 x 1000 x 10.000 =440.000 m3
More questions
• Give an estimate of the storage in the surface water.
• Average height (1,1 + 0,8)/2 = 0,95 m
• Assume rectangular ditch• 11,2 x 10.000 x 0,95 = 106.400 m3
And more questions!
• Suppose the entire area of 1000 ha is flat, will it submerge? (simpel approach to the problem)
• Rainfall 1.000.000 m3• Discharge pump 440.000 m3• Storage surface water 106.400 m3• Storage in soil 0,95 x 10 x 60.000 = 570.000 m3• Total of storage + discharge =1.116.400 m3• Answer is no, differences in height are needed, so
the water can flow to the lowest points.
Calibration!!!!
• Which information do you need for a good calibration?
• Precipitation• Variances in water level• GWL at the start of the rain shower• Discharge of the pump• Model that can be modified
Winter
• Area 1gsl +0,8 mDepth drainage 1 mWinter level (weir) -0,5 m , dry height 1,3 mGWL is 0,5 m below ground surface level
• Area 2gsl +0,1 mDepth drainage 0,7 mWinter level (pump) -0,9 m , dry height 1,0 mGWL is 0,5 m below ground surface level