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Laboratory Teaching Exercises

Index to Exercises

Exercise A - Rainfall-Runoff Relationships (Storm Hydrographs)

Exercise B - Generation of Overland Flow

Exercise C - Initiation and Characteristics of Bedload Motion

Exercise D - Effect of Changing Stream Power on Channel Morphology

Exercise E - Effect of Base Level Change

Exercise F - Scour in Open Channel Flow

Exercise G - Water Abstraction from a Well in a Confined Aquifer

Exercise H - Water Abstraction from a Well in an Unconfined Aquifer

Exercise I - Water Abstraction from a Number of Neighbouring Wells

Exercise J - Rainfall on a Circular Island with a Central Well

Exercise K - Ground Water Flow between Two Canals With and Without Rainfall

CAUTION:

Although the sand tank cannot move suddenly when adjusting the

elevation, extreme care should be taken when operating the jacks to prevent
crushing of fingers, hands or other objects between the upper and lower frames.

General Equations and Constants

Equations

Discharge (m³/s) = Discharge (l/min) x (50/3)

Average channel depth (or width) (m) = Sum of depths (or widths) (m)

number of

depth (or width) measurements taken

Rainfall Intensity (mm/hr) = ((Rainfall Flow Rate (l/min) x (50/3

Catchment Area

(m²)) x (5/18)

Sediment Transport Rate (kg/ms) = (Sediment Yield (kg)

Time taken (s))

Average width (m)

Sediment Transport Rate (kg/s) = Sediment yield (kg)

Time taken (s)

Valley Slope (%) = Reading from scale on end of simulator

Darcy’s Equation =

Thiem’s Equation =

Содержание S12-MKII

Страница 1: ...Advanced Environmental Hydrology System Instruction Manual S12 MKII ISSUE 21 February 2014...

Страница 2: ...Water Feeds 10 Sand Tank 11 Outlet Collecting Tank 12 S12 MKII 50 S12 MKII Including Data Logging and Educational Software 12 Overhead Spray Nozzles 13 River Inlet Tank 13 Choice of Granular Material...

Страница 3: ...Generation of overland flow 37 Exercise C Initiation and characteristics of bedload motion 39 Exercise D Effect of changing stream power on channel morphology 42 Exercise E Effect of base level change...

Страница 4: ......

Страница 5: ...Customer Support helpdesk Monday to Thursday 0830 1730 and Friday 0830 1300 UK time Contact details are as follows United Kingdom International 0 1425 478781 calls charged at local rate 44 0 1425 4787...

Страница 6: ...l cycle bounded by the arrival of net rainfall on the ground surface and catchment run off either by surface streams or well abstraction The hydrological cycle describes the complete movement of water...

Страница 7: ...n excavations and the drainage of lakes and polders Geologists and geographers are frequently faced with problems which involve hydrological processes such as drawing up a water balance for a catchmen...

Страница 8: ...4 Equipment Diagrams Figure 1 Front View of S12 MKII Hydrology System...

Страница 9: ...Equipment Diagrams 5 Figure 2 Plan View of S12 MKII Hydrology System...

Страница 10: ...Armfield Instruction Manual 6 Figure 3 End View of S12 MKII Hydrology System...

Страница 11: ...erous the RCD will switch off the electrical supply and reduce the severity of any electric shock received by an operator to a level which under normal circumstances will not cause injury to that pers...

Страница 12: ...organisms The COSHH Regulations The Control of Substances Hazardous to Health Regulations 1988 The COSHH regulations impose a duty on employers to protect employees and others from substances used at...

Страница 13: ...Appropriate storage and handling Although these regulations may not be applicable in your country it is strongly recommended that a similar approach be adopted for the protection of the students oper...

Страница 14: ...verflow pipe 2 on the side of the side of the sump tank ensures that the tank cannot be overfilled A drain valve 6 is connected to a tapping at the base of the sump tank The centrifugal pump draws wat...

Страница 15: ...Two cylindrical wells 19 are also included in the sand tank floor The wells are covered with stainless steel mesh to prevent the loss of sand Valves and pipework beneath the sand tank allow the water...

Страница 16: ...sediment fall into the open area of the tank A vertical mesh screen 30 supported by perforated plates on either side ensures that sediment is retained in the tank The water flows through the mesh alo...

Страница 17: ...zle allows the pattern to be changed as required Since the flowrate through each nozzle is dependent on the pressure if the appropriate pressure regulator 12 is adjusted to give the required flowrate...

Страница 18: ...ed If this is necessary then the sand must be given multiple washes with intermediate drying on trays to eliminate the soluble salts etc The sand should also be graded using sieves to remove those fra...

Страница 19: ...m high Large rectangular closed ring with hole 1000mm x 500mm x 60mm b Impermeable catchment 1000 gauge Polythene sheet sufficient to cover the catchment area c Permeable catchment Sheets of absorbent...

Страница 20: ...GREEN YELLOW EARTH BROWN LIVE HOT BLUE NEUTRAL Supply fuse rating 5 AMP S12 MKII B or S12 MKII 50 B The equipment requires connection to a single phase fused electrical supply The standard electrical...

Страница 21: ...Laboratory Drain A drain will be required at floor level for draining the system during maintenance using the drain valve 6 at the base of the sump tank It is not necessary to provide a permanent conn...

Страница 22: ...lied 5 Adjust the inclination of the sand tank to zero shown by the level indicator 36 using the scissor jacks 34 at the right hand end of the frame The jacks are operated by inserting the loose jack...

Страница 23: ...oth flowmeters Make sure that the in line valve on both French drains is fully open Open both feed flow control valves 13 below the flowmeters then adjust both pressure regulators 12 to give maximum f...

Страница 24: ...stop logs approximately half full Switch off the pump and close the feed flow control valves 14 Place a single drop of wetting agent in each manometer tube 20 to minimise the effect of surface tension...

Страница 25: ...ressure sensor on the side of the collecting tank that is used to measure the water level Fill the plastic syringe with water then insert the catheter through the tapping Gradually inject water into t...

Страница 26: ...C A flexible tube connected from a pressure sensor inside the data logger is connected to the collecting tank via a Guest quick release connector to measure the water level inside the collecting tank...

Страница 27: ...he software is split into three parts to suit the different exercises associated with S12 MKII Part 1 of the software is used to determine the Sand Factor voidage of the sand used in the sand tank Par...

Страница 28: ...zero the reading fill the collecting tank until water flows out over lowest point of the weir Wait for the level to settle and stop flowing over the weir then press the Zero button The Height and Out...

Страница 29: ...ory or similar such place invalidates conformity with the protection requirements of the Electromagnetic Compatibility Directive 89 336 EEC and could lead to prosecution Environmental Conditions This...

Страница 30: ...ement to prevent water loss when it is disconnected prevents water in the tank from draining onto the floor If it is necessary to drain the river inlet tank then the loose quick release fitting suppli...

Страница 31: ...sary against Legionella or other hazardous micro organisms Refer to the notes on Water Borne Hazards within the Important Safety Information section If the temperature of the water will exceed 20o C i...

Страница 32: ...ectronic load sensor fitted to S12 MKII 50 When the optional data logging accessory is fitted the electronic sensor used to measure the total weight of the outlet collecting tank may require re calibr...

Страница 33: ...tral Well Exercise K Ground Water Flow between Two Canals With and Without Rainfall CAUTION Although the sand tank cannot move suddenly when adjusting the elevation extreme care should be taken when o...

Страница 34: ...er N m x Hydraulic radius m x Slope m per m Shear Velocity g x Hydraulic radius m x Slope m per m Boundary Reynolds Number Shear velocity m s x Grain diameter m Kinematic viscosity m s Shields Paramet...

Страница 35: ...Laboratory Teaching Exercises 31 Total Sinuosity Total thalweg length m Valley length m Nickpoint Speed cm min Distance travelled by nickpoint cm Time taken to move distance min...

Страница 36: ...horizontal distance it has to travel and also on the velocity Figure A1 shows lines of equal flow time for a catchment of similar proportions to the model in which the flow velocity is everywhere the...

Страница 37: ...arallel to the top edge of the tank then use the sand scoop to create a channel of rectangular cross section centrally down the length of the tank between the river inlet and the deep outlet at the fo...

Страница 38: ...Armfield Instruction Manual 34 Proceed as in a but cut off rain while hydrograph is still rising Figure A4 will result Figure A4 Figure A5...

Страница 39: ...ing double hydrograph when plotted will show the much larger run off values obtained for the second storm which falls on a previously saturated catchment The method for drawing the hydrograph outlined...

Страница 40: ...tank and their effects on the run off hydrograph of a standard storm compared Results Description of catchment area and initial channel planform Sketch of catchment area Time since start of run secs R...

Страница 41: ...or valley leading to the deep cut out at the foot of the tank Include areas where overland flow would be expected to form such as areas close to the water table and or areas of flow convergence Keep t...

Страница 42: ...d flow including source areas use references to sketch above Conclusions What conditions produced the best examples of overland flow What factors may have contributed to its development Did overland f...

Страница 43: ...cal threshold of motion CR is crossed and sediment grains start to move along the channel bed At flow intensities just above the threshold of motion sediment particles move by rolling and sliding alon...

Страница 44: ...sediment yield measurements at each stage Each run should last for 20 25 minutes with sediment yield measured every five minutes or more frequently for high sediment flow rates The channel should be...

Страница 45: ...Basing your conclusion on your observations is there a specific threshold of motion for river bedload If so is there a defining relationship between bed slope river flow rate Shields parameter and in...

Страница 46: ...ough the degree of meandering can vary considerably Meandering is associated with intermediate valley slopes steeper than those of straight channels but less than those leading to braiding bed sedimen...

Страница 47: ...hange during this time Make notes on the presence of features such as bars terraces scour holes and the position of the channel thalweg Measure the channel length by laying a piece of string along the...

Страница 48: ...the sand surface in steps across the entire width of the tank Reference points should be recorded for any notable features such as the positions of the channel sides sand bars sub channels and thalweg...

Страница 49: ...onveyance capacity and localised flooding Procedure Connect the flexible piping from the river inlet tank to the quick release connector on the 5 l min flow meter Fit one of the two 50mm stop logs int...

Страница 50: ...to the end and then moved along the tank in steps of 10cm At each position the second ruler is then used to measure the distance from the top line of the tank to the sand surface in steps across the e...

Страница 51: ...tank Set the slope of the sand tank to approximately 2 Smooth and lightly tamp down the sand level with the top of the sand tank Use the scoop provided to cut an initial straight channel into the sed...

Страница 52: ...the second ruler is then used to measure the distance from the top line of the tank to the sand surface in steps across the entire width of the tank Reference points should be recorded for notable fe...

Страница 53: ...rise in a borehole which penetrates the cover until an equilibrium pressure is obtained at the bottom of the borehole Figure G1 The imaginary surface which contains the water surfaces in any such bore...

Страница 54: ...ed at this level large enough to take the closed ring arranged with its centre opening over the well tube The closed ring is now placed in position with its transparent central standpipe sight tube in...

Страница 55: ...ngs It is also possible to prepare a plan from these graphs showing piezometric surface contour lines Abstraction from a single well in a confined aquifer of rectangular plan The apparatus is set up i...

Страница 56: ...re values obtained with the manometer tubes Results Volume collected I Time to collect sec Q0 m3 s H m Tapping position m Manometer readings m S H manometer reading Calculate k from one of the two equ...

Страница 57: ...e water table Figure H1 Ground water abstraction from a well will again result in the lowering of the water table but in the unconfined aquifer under consideration this means at the same time a reduct...

Страница 58: ...vation can be drawn from the manometer readings for abstraction from the centrally placed well and from these a contour plan of the water table surface may be prepared So long as the coefficient of pe...

Страница 59: ...Exercise H 55 Calculate k from one the equation provided in the theory Conclusion Compare the results obtained with typical permeability values of different types of aquifer...

Страница 60: ...to small drawdown values it is suggested that small Qo values should be used Draw the required flows from each well in turn measuring the drawdown produced in each case with the manometers Now establ...

Страница 61: ...lake This situation differs from the excavation dewatering problem in that the drainage takes place from the floor of the polder This means that ground water flows into the polder is collected in a r...

Страница 62: ...Armfield Instruction Manual 58 Results Conclusion Did the results observed fit with the results predicted by theory Suggest reasons for any differences...

Страница 63: ...rately to the position of the ring and other ground features The water filled ditch surrounding the island serves to isolate its ground water conditions from effects outside In the second part of this...

Страница 64: ...dding the water tables determined previously under each separate ground water flow Results Rainfall Flow Rate ______ l min Ground Water Inflow Rate ______ l min Tapping position m Manometer reading ra...

Страница 65: ...rench drain on the same side as the highest of the two canals and turn on the water supply This will establish the ground water flow without recharge and the correct flow can be found by experiment Co...

Страница 66: ...n Manual 62 Conclusion Did the experiment suggest that the theory of superposition is applicable to this simulation How might simulations of this type be applied to civil engineering projects such as...

Страница 67: ...West Street Ringwood Hampshire England BH24 1DY Tel 44 0 1425 478781 Fax 44 0 1425 470916 Email sales armfield co uk support armfield co uk Web http www armfield co uk US Office Armfield Inc 9 Trento...

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