Presentation on theme: "Sun wind water earth life living legends for design (AR1U010 Territory (design), AR0112 Civil engineering (calculations)) Prof.dr.ir. Taeke M. de Jong."— Presentation transcript:
Sun wind water earth life living legends for design (AR1U010 Territory (design), AR0112 Civil engineering (calculations)) Prof.dr.ir. Taeke M. de Jong Drs. M.J. Moens Prof.dr.ir. C.M. Steenbergen http://team.bk.tudelft.nl
Publish on your website: AR1U010 how you could take water, networks, traffic and civil works into account in your earlier, actual and future work. AR0112 calculation and observations of streams in any location and your design, check your observations As soon as you are ready with all subjects (Sun, Wind, Water, Earth, Life, Living, Traffic, Legends), send a message mailto:M.E.Wenmeekers-Thomas@bk.tudelft.nl referring your web adress, student number and code AR1U010 or AR0112.mailto:M.E.Wenmeekers-Thomas@bk.tudelft.nl
Q by measurement The velocity v of water can be measured on different vertical lines h with mutual distance b in a cross section of a river. You can multiply v x b x h and summon the outcomes in cross section A to get Q = (v*b*h).
Q(height) Normal representationLogarithmic representation
Hydrolic radius Cross length (Natte omtrek) by Pythagoras: Surface wet cross section: A P H Hydrolic radius:
Method Chézy The average velocity of water v = Q/A in m/sec is dependent on this hydrolic radius R, the roughness C it meets, and the slope of the river as drop of waterline s, in short v(C,R,s). According to Chézy v(C,R,s)=C Rs m/sec, and Q = Av = AC Rs m 3 /sec. Calculating C is the problem.
Method Strickler-Manning Instead of v=C Rs, Strickler-Manning used
Method Stevens Instead of v=C Rs Stevens used v=c R considering Chézys C s as a constant c to be calculated from local measurements. So, Q = Av = cA R m 3 /sec When we measure H and Q several times (H 1, H 2 …H k and Q 1, Q 2 … Q k ), we can show different values of A(H) R(H) resulting from earlier calculation as a straight line in the graph below. Surface wet cross section: Hydrolic radius:
Reading Q from H by Stevens When we read today on our inspection walk a new water level H1 on the sounding rod of the profile concerned we can interpolate H1 between earlier measurements of H and read horizontally an estimated Q1 between the earlier corresponding values of Q to read Q from graph.
Hydrographs River with continuous base discharge River with periodical base discharge
Using drainage data Duration lineDataset with peak discharges
Peak discharges The peak discharge Q T exceeded once in average T years (return period) is called T-years discharge. The probability P of extreme values is called extreme value distribution. The complementary probability P = 1 P discharge Q will exceed an observation (Q>X) is 1/T and the reverse P = 1 – P = 1 – 1/T. So, the reduced variable y = -ln(-ln(1 – 1/T)). Now we put in a graph: and
Constructing Gumble I paper T(y) and P(y)LogaritmicallyGumbel I paper
Storage When surface A varies with height h storage S is not proportional to height. By measuring surfaces on different heights A(h) you get an area-elevation curve. The storage on any height S(h) (capacity curve) is the sum of these layers or integral
Capacity calculation You can simulate the working of a reservoir (operation study) showing the cumulative sum of input minus output (inclusive evaporation and leakage). The graph is divided in intervals running from a peak to the next higher peak to start with the first peak. For every interval the difference between the first peak and its lowest level determines the required storage capacity of that interval. The highest value obtained this way is the required reservoir capacity.
Lowlands with spots of recognisable water management
Water managemant tasks in lowlands 05 Urban hydrology06 Sewerage 07 Re-use of water 08 High tide management 09 Water management10 Biological management 11 Wetlands 12 Water quality management 13 Bottom clearance14 Law and organisation15 Groundwater management16 Natural purification 01 Water structuring02 Saving water 03 Water supply and purificatien 04 Waste water management
Distance between trenches The necessary distance L between smallest ditches or drain pipes is determined by precipation q [m/24h], the maximally accepted height h [m] of ground water above drainage basis between drains and by soil characteristics. Soil is characterised by its permeability k [m/24h]. A simple formula is L=2 (2Kh/q).
Hooghoudt formula A simple formula is L=2 (2Kh/q). If we accept h=0.4m and several times per year precipitation is 0.008m/24h, supposing k=25m/24h the distance L between ditches is 100m. However, the permeability differs per soil layer. To calculate such differences more precise we need the Hooghoudt formula desribed by Ankum (2003).