Abstract: A drainage system for a natural turf athletic field includes a buried drainage network located above a water impermeable membrane which conforms to the topography of a compacted subsoil, the drainage network including a plurality of water impermeable pipe rows partially recessed in depressions in the subsoil and a plurality of water permeable conduit rows oriented perpendicular to and intersecting the pipe rows. At each intersection, a low profile coupling interconnects the respective pipe row to the respective conduit row, the coupling having a vertical dimension less than the combined vertical dimension of the pipe rows and the conduit rows. A fill layer covers the membrane and supports natural turf thereabove. The drainage network connects to a a gravity drain and a water supply. The design of the drainage network results in reduced excavation and simplified construction, thereby lowering the installation cost for the system.

Abstract: In a drainage pump station, a driving machine has a capacity greater than a shaft power necessary for no-discharge operation of a pump, and during severe flooding the pump is operated at an overload exceeding its design capacity. During maintenance operation water is fed from a river on the delivery side of the pump station into the station. When an inflow of rainwater into the pump station is great the pump is operated at the necessary capacity, when it becomes small the water level is kept above a rated value, and when the inflow rate is zero the pump discharge is increased to a capacity at which sediment can be discharged. A suction blower is disposed at the top of a suction sump and interstage valves are disposed in entrances of vertical shafts to effect efficient ventilation of the underground waterway. A feed channel is operated as a pressure channel and the pump is of variable capacity and the water level in the underground waterway is controlled to be constant.

Abstract: An apparatus for soil irrigation control comprising a control unit, a soil probe, and a temperature probe. The function of the invention is to provide day-to-day soil moisture measurement and control of the irrigation system it is attached to, usually a timer operated system. During operation, the control circuitry periodically measures the apparent electrical resistance between the two electrodes of the soil probe. A signal related to the measured resistance is then compared to a reference set by the user and functions to close or open an electrical switch that ultimately controls the application of irrigation water. The apparatus has a temperature sensor to compensate for effects upon the moisture sensor due to changes in soil temperature, and to also suspend irrigation when freezing conditions are pending. The apparatus also detects the presence of a external timer signal and sustains irrigation through completion of the timer cycle even though the moisture sensor may become wetted during the cycle.

Abstract: Soil adjacent to an elongated furrow is irrigated by flowing the water from a header into and along the furrow, and erosion of the furrow is reduced and infiltration into the soil is increased by dissolving solid flocculant in the header or in the furrow into the water. The solid flocculant is best provided as a block of particulate flocculant bonded by a water-soluble wax. The irrigation process is best conducted on a cyclic basis with the solid flocculant being removed from the header or furrow during the cycle and with the supply of water being continued so that there is subsequent run-off of water from the furrow.

Abstract: A vertical-shaft multi-stage pump has adjustable vanes on its lower stage. A vane angle operating mechanism has an operating shaft extending through a hollow portion of the drive shaft of the upper stage and a link mechanism connected to the operating shaft and the adjustable vane impeller for converting axial motion of the operating shaft into vane angle rotational motion. The pump is particularly suited for use in an underground drainage system.

Abstract: An automated furrow irrigation control method and system involves the initiation of an irrigation flow into an upstream end of a furrow at an initial water discharge rate; continuously or periodically sensing the progress of water flow along the furrow; continuously or periodically increasing the water discharge rate in response to the sensed progress of the water flow so as to ensure a substantially continuous flow in the furrow at a flow rate which lies substantially between .+-.30% of a constant value; sensing the arrival of the water flow at a downstream end of the furrow; reducing the water discharge rate in response to the sensed arrival of the water flow at the downstream end of the furrow; sensing the percolation of the water flow at the downstream end down to a predetermined depth; and terminating the irrigation flow in response to the sensed percolation.

Abstract: A plurality of drainage pumps are disposed on a high floor gradation state in a circular arrangement. A plurality of drainage pumps are disposed on a low floor gradation state in a circular arrangement. The drainage pumps disposed on the high floor gradation are installed at a high level, with the drainage pumps having a low pump head and a large capacity in comparison with the drainage pumps disposed at the low floor gradation. An outer shape of an underground pump construction building is in the form of a circular cone shape spreading toward an upper portion of the underground pump construction building. The amount of power for discharging the drainage can be reduced and the construction area for the underground pump construction building can be reduced thereby minimizing the necessary requirement for installation of the underground pump construction.

Abstract: A system is provided for controlling the moisture content of a planted surface. The system includes a plurality of drain conduits located beneath the planted surface for collecting liquid from the planted surface. The system also includes a sealed collection tank coupled to the plurality of drain conduits. The collection tank is located beneath the planted surface to collect liquid passing through the plurality of drain conduits. The system also includes a vacuum pump coupled to the collection tank for removing air from the collection tank to provide a suction force in the collection tank and in the plurality of drain conduits to draw liquid from the planted surface through the plurality of drain conduits and into the collection tank. An elevated air tank is coupled between the vacuum pump and the collection tank. The elevated air tank is located at a remote location spaced apart from the collection tank.

Abstract: A treatment system for aerating, cooling and heating or draining a site such as a golf course green or a playing field. A mobile blower can be connected and disconnected with an underground duct network situated under the site through a suitable valving arrangement so that one blower can be used in servicing a number of sites.

Abstract: A device for ensuring free flow to roof rainwater outlets, especially on flat roofs, in connection with ice formation. The device comprises a feed means (1) in the form of at least one channel member (2) extending outwards from a gully (4) and being provided with a plurality of side inlet openings (6) along its length, and a heating cable (11) arranged within the channel member (2) and which is arranged to be thermostatically connected within a chosen temperature interval, to melt ice which has formed around the gully (4). The temperature interval of the thermostat suitably is ca. 2.degree. C. and this interval preferably is displaceable within a chosen temperature range, e.g. between -5.degree. C. and 0.degree. C. Alternatively, the thermostat records the surface temperature of the roof covering and connects the heating cable (11) when the temperature rises and passes 0.degree. C.

Abstract: A plural drainage pumps PH are disposed on the high floor gradation state at the circular shape. A plural drainage pumps PL are disposed on the low floor gradation state at the circular shape. The drainage pump PH disposed on the high floor gradation is installed at the high level. The drainage pump PH is set one having the low pump head and the large capacity in comparison with those of the drainage pump PL disposed on the low floor gradation. An outer shape of an underground pump construction building is formed a circular cone shape spreading toward an upper portion. The discharge water power can be reduced and the construction area for the underground pump construction building can be reduced and further the engineering working amount such as a digging working at the underground can be lessen.

Abstract: A gray water reclamation system is disclosed. The system includes a gray water filter and a gray water conduit for receiving exclusively gray water from at least one household source and passively delivering the gray water through a water filter to remove impurities therefrom. Filtered water is temporarily stored in an underground tank. A sensing apparatus such as a pressure tank determines when gray water is required by an outside irrigation system, inside toilets or other appliances. Suitable controls direct a pump to transmit water from the storage tank to either irrigation apparatus or, after further filtering, to appliances in need of water.

Abstract: An underground water channel is provided in an underground of a large depth, and rain water and the like flow into this underground channel from flood control channels, conduits and rivers through vertical shafts. A pump well of a pump station is connected to a downstream end of the underground channel, and water flowing into the pump well is discharged by a pump to a discharge tank. The pump is disposed generally at a medium water level of the underground channel, and a lowest water level L.W.L enabling draining is the medium water level of the underground channel. In an open channel flow operation of an open channel-closed channel mixed flow operation, water level of the underground channel is maintained at the lowest water level L.W.L, so that the underground channel is in an open channel condition.

Abstract: A fitting for mating a fluid flow main line, such as a sewage disposal line, with a branch line to a residence, industrial building, or commercial building intended to be serviced. The fitting is mated to a T interposed in the main line which the branch line is intended to intersect. The fitting is, in turn, at its end opposite that by which it is mated to the T, interfitted to the branch line to provide for relative telescoping movement between the fitting and the branch line. Damage to the main line as a result of settling of the earth in which the branch line is buried is protected against.

Abstract: An underground drainage facility including a drainage pump adapted to be operated if an inflow water channel is constructed as a closed channel. Overflow weirs in water channels such as rivers or the like on an inflow side are less than a maximum water level. A vertical-shaft multi-stage adjustable-vane impeller is used as a drainage pump. Consequently, even a drainage pump of a high pressure head and large capacity can perform a waiting running and accommodate a variation in a quantity of inflowing water to the drainage facility.

Abstract: A system is provided for controlling the moisture content of a planted surface. The system includes a plurality of drain conduits located beneath the planted surface for collecting liquid from the planted surface. The system also includes a sealed collection tank coupled to the plurality of drain conduits. The collection tank is located beneath the planted surface to collect liquid passing through the plurality of drain conduits. The system also includes a vacuum pump coupled to the collection tank for removing air from the collection tank to provide a suction force in the collection tank and in the plurality of drain conduits to draw liquid from the planted surface through the plurality of drain conduits and into the collection tank. An elevated air tank is coupled between the vacuum pump and the collection tank. The elevated air tank is located at a remote location spaced apart from the collection tank.

Abstract: An apparatus for use in conjunction with a silt collecting pond to prevent silt from being washed from adjacent land by rainwater comprises a base adapted to rest on the bottom of the pond and a cylindrical cage defining an upwardly open interior volume extending upwardly from the base. A conduit communicates between the interior volume of the cage and the exterior of the pond. Silt cloth is mounted about the cage and a floatable safety lid is adapted to cover the upper opening of the cage. In operation, silt bearing rainwater enters the pond and rises about the apparatus. Water passes through the silt cloth at a predetermined rate such that the water stands in the pond a sufficient time to allow silt to precipitate therefrom. When the pond has been filled with silt, a sleeve is slipped into the cage and a grated lid placed atop the sleeve so that the device thereafter provides for drainage of surface rainwater from the land.

Abstract: A hydraulic diverter comprises a pair of tubes connected to receive water from a storm drain. One of the tubes is connected to discharge the water into a basin, while the other is connected to discharge water and bed sediment load into a bypass line. The storm water flow is preferentially directed through one tube or the other by changing the relative elevations of the tubes. The tubes are coupled together to change elevations by a pulley system or a swivel system. The pollutant laden "first flush" flow of storm water is diverted to the basin, while subsequent or "sustained" flow transporting bed sediment load is directed through the bypass line. The storm water itself is utilized to change the relative elevations of the tubes when the storm water flow transitions from a first flush flow to a sustained flow.

Abstract: A moisture sensing device (2) operating according to the tensiometer principle which in the case of complete drying out emits the same signal as on reaching the maximum moisture content, in the case of complete drying out emits a signal corresponding to that with the minimum, set moisture content. A drying out prevention means (40) provided for this operates with the same contactor (24) and is operated by the same control member (18) as the sensing device (2) in normal operation. The switching point for the drying out prevention means (40) can be adjusted by means of an adjusting device (48). However, the water supply is switched on by the signal emitted on drying out.

Abstract: A positively closing nozzle and method of its use in underground irrigation wherein the nozzle is elongated with inlet means at one end and positively closing means at the other end opened by water pressure applied to the nozzle, one or more nozzle being arranged underground in a selected pattern for irrigating plants or the like, the valve being operated by water pressure for producing a circumferential flow pattern of irrigation, the flow pattern being adjustable either by means of a spring-load or flow emitter means in the nozzle.

Abstract: A waste water treatment and disposal system for further treating waste water effluent from a primary treatment system in which a system controller controls the operation of the system. A dosing tank accepts effluent from a primary treatment system and is evacuated on demand by a pump which is energized in response to a fluid level switch in the dosing tank. The pump forces the effluent through a filtering system to remove solid waste therefrom, and then forces a portion of the filtered effluent into a hydro-pneumatic pressure tank which, upon call, will backflush the filter to remove the trapped solids therein. The system controller will monitor the system to operate the level of the dosing tank, the operation of the pump and the various valves which control the flow throughout the system. The filtered effluent will ultimately be discharged into a disposal area by any number of well known methods.

Abstract: A water backflow preventing system is provided for a given area having a sewer line for receiving rain and other water where the sewer line is incapable of carrying, without backup, a given flow rate of water. The sewer line is provided at a given point therealong with at least one overflow opening into which opening water which cannot be handled by the sewer line will rise and overflow. Water storage tank means are buried in the ground below the sewer line and into which the overflow water from said opening will drain and be temporarily stored. The storage tank means have a volume to store many thousands of gallons of water which cannot otherwise flow in the sewer line. A pump is placed in the bottom of the storage tank means. Various float switches are placed in different parts of the system for controlling the pump.

Abstract: An apparatus for containing liquids and pollution within a liquid drainage comprising a first conduit, a second conduit, a liquid barrier, a means for lifting, and a means for sensing pollution. The second conduit is smaller in relative diameter than the first conduit and is positioned so that the second conduit outlet end is located within the first conduit. The second conduit has a flexible portion of its length which permits the outlet end of the second conduit to be lifted while the inlet end of the second conduit remains stationary. The liquid barrier guides fluid flow into the second conduit inlet during normal flow, guides fluid flow into the second conduit and liquid flow over the top of the liquid barrier and into the first conduit during floods and retains liquid during normal flow when the outlet end of the second conduit is lifted. The apparatus further comprises a means for lifting which is electrically connected to a sensing means.

Abstract: In a drainage system wherein drain water is collected from a drainage path including a small river, guided to a plurality of drainage pump facilities, and drained into a destination river, a drainage distribution amount is determined for each of the plurality of drainage pump facilities in accordance with an actual precipitation or estimated precipitation, a river water level at a drainage point of each of the plurality of drainage pump facilities is estimated in accordance with the drainage distribution amount and a change in a detected water level at an upstream of the destination river, and the drainage distribution amount for each of the plurality of drainage pump facilities is corrected so as to make the estimated river water level have a value equal to or smaller than an upper limit of the river water level at the drainage point.

Abstract: An irrigation system comprises a pump facility 11 for pumping up seawater from the sea, an artificial seawater lake 31 formed in an inland area, a freshwater producing plant 41 for producing freshwater from seawater, an artificial freshwater lake 51, and an irrigation canal 61 for supplying the freshwater to a projected irrigation area. A solar-cell power generation plant 21-25 is constructed for supplying electric power to operate the irrigation system. The irrigation including the artificial seawater lake is formed in an inland area in a comparatively short time, and freshwater is produced from the seawater stored in the artificial seawater lake. Therefore freshwater can be supplied to a projected irrigation area at an early stage of the construction of the irrigation system.

Abstract: An underground system for supplying water to and removing water from an athletic facility having a surface which is susceptible to excessive moisture and dryness. The system includes an array of pipes which are positioned within rectangularly cross sectioned trenches having substantially level bottoms. Water is supplied to and removed from the array of pipes by a water control system at ambient pressures. The system may be installed into existing athletic facilities without excessive damage or disruption to their surfaces.

Abstract: Water is removed from an underground perforated pipe by a submersible pump inserted into an imperforate pipe extending from above ground to below ground level for communication with the perforated pipe. An inflatable bladder seals the submersible pump to the inner wall of the imperforate pipe for facilitating suction of water from the perforated pipe into the imperforate pipe. Water is drawn into a proximal end of the pump and expelled out of a distal end of a pump, and out of the imperforate pipe above ground level. By sealing the pump to the inner wall of the imperforate pipe, the pump is capable of drawing water from an underground perforated pipe located at a depth greater than the pumping capacity of the pump for drawing up water.

Abstract: A valve is installed into an underground conduit to control drainage of water through that conduit. The drainage control valve includes a perforated plate across the conduit. The latter plate is formed with a peripheral groove rectangular in cross section and a hollow tube made of flexible material is inserted into this groove to seal the joint between the plate and the inner surface of the conduit. A flap also made of flexible material is applied against the upstream surface of the plate and is formed with a peripheral edge taper whereby pressure applied on the flap by water upstream of the drainage valve forces the edge taper against the upstream plate surface to form a sealed joint between these flap and plate. The upper portion of the flap is attached to the upper portion of the plate through screw and nut assemblies. These assemblies traverse rigid washers inserted in respective holes made in the flap.

Abstract: Preferably for irrigation purposes wherein a sloping conveyance includes multiple and like sized orifices aligned therealong in near level relationship to thereby provide diverted water balanced access to the orifices. A uniflow system incorporating sloping supply, downstream valved-riser and orifice line segmentation in relative position whereby selective valve actuation causes a diversion to well-up to and out the orifices simultaneously and thereby cause the automatic distribution of duplicated flow to the land. Actuator assembly mounting automates the diversion. Actuator mounting in communication with a remote controller further automates diversions through systems programming.

Abstract: A water backup monitoring system for a buried sewer line is provided, the sewer line being provided at a given point therealong with at least one overflow opening into which opening water which cannot be handled by the sewer line will rise and overflow. A manhole extends between the sewer line and the surface and surrounding said overflow opening to permit a man to gain access to the area of said overflow opening. A standpipe in the manhole communicates with the overflow opening, into which standpipe water rises when backflow conditions exist in the sewer line. A backflow-indicating tube is provided outside of this standpipe, and into which backflow water flows from the overflow opening so that the water in the backflow-indicating tube and the standpipe are at the same level. The tube provides an indication of the level of the water therein. A one-way valve in the tube permits water to rise in the tube, but prevents it from draining therefrom.

Abstract: The present invention is a self-contained residential and commercial treatment system which is capable of purifying waste water and then distributing the purified water by means of a sprinkler system or a drip feed irrigation system or of recycling the purified water in some manner.

Abstract: The disclosure herein describes a control device for use with an underground drainage and irrigation network formed of a main conduit line and of adjacently disposed water permeable secondary conduit lines. At least one head control stand is used defining a water-collecting chamber with a pair of float members therein. These floats are operatively connected to respective drainage and irrigation control valves. The chamber communicates with an underground duct having a free, perforated end positioned between a pair of secondary lines to collect underground water received in the chamber to influence the floats. The valves are operated by the floats to maintain an underground water table between the two adjacent secondary lines at a level adequate for optimal plant growth.

Abstract: A surface, subsurface continuous feed moisture maintenance system for microscopic volume irrigation utilizing a preset flow rate valve, provided in a single preset flow rate stage or multiple preset flow rate stages, a moisture actuated sensor valve and a plurality of permeating, moisture distribution tubes. The preset flow rate valves are selected and set according to plant moisture needs in the geographical area being irrigated. The moisture actuated sensor valve gradually opens or closes water flow to the system according to soil moisture level conditions and thus prevents over watering and conserves on water resources. The moisture permeating action of the distribution tubes complement the preset flow rate of the valve and the moisture actuated sensor valve to maintain the subsurface at a constant moisture level.

Abstract: The disclosure herein describes a control device for use with an underground drainage network of main collectors and adjacently disposed water-collecting pipes. A head control stand is used defining a water-collecting chamber with a float member therein. The latter is operatively connected to a valve disposed in an associated main collector and is opened as a result of the float member being influenced by the measurement of the water table depth between two adjacently disposed water-collecting pipes of the network. The valve remains opened as long as the level of underground water exceeds a value corresponding to optimal plant growth.

Abstract: A drainage valve for use in pressure systems where pressure surges occur for draining an underground water system when the water pressure in the underground water system is off and for sealing the drainage valve against drainage when the water pressure is on comprising a housing having a first annular support and sealing surface and a second annular support and sealing surface for supporting a member that is nonextrudable through a drain passage in the drainage valve under normal operating pressures and surge pressures encountered in water supply systems and to permit said nonextrudable member to open said drain passage when the water pressure is off.

Abstract: The disclosure relates to a built-up playing court structure having a stable moisture content controlled surface layer with playing qualities equivalent to conventional clay courts. The playing court structure comprises a built-up court surface layer, a barrier surface which is substantially impervious to moisture, a containment wall, a subsurface bed of aggregate, and means for controlling the moisture content of the court surface. A subsurface moisturizing and drainage system provides a horizontal playing surface, highly resistant to any washing away of surface materials. Controlling surface moisture also provides a consistent playing surface with no loss of surface materials due to wind.

Abstract: An apparatus is described that has been created to maintain a constant level of saturation of water near the foundation of houses, buildings, or the like. The maintenance of such a level of moisture is essential to the structural integrity of foundations especially in those geographic locations where the level of soil moisture varies significantly from season to season. Soil, when it absorbs water, expands. This soil can exert tremendous pressure on the foundation of a house. To prevent cracking of foundations, and thus, to prevent the need for costly repairs, the apparatus described herein provides sufficient moisture to the soil surrounding the foundation of a house such that additional moisture (i.e. rain) does not cause the soil to expand dramatically.

Abstract: A device for protecting irrigation land local flooding caused by damaged sprinklers or broken risers. The device, in accordance with the present invention is designed to be situated within a piping component upstream of each individual sprinklers and it is completely enclosed within the piping component. The device detects and responds to the excess flow caused by damaged sprinkler or broken riser by shutting off water to the damaged sprinkler. In so doing, the device allows the remainder of the irrigation circuit to operate without interruption, albeit temporarily without the service of the damaged sprinkler. The device has no external housing and therefore the component itself is not vulnerable to physical damage from outside.

Abstract: In one aspect a novel valve, when used with water conveying conduits of water supply or of irrigation systems, will purge them of residual water in the conduits, when the water supply is "cut off", but will close the system when the water supply is on (e.g. there is water pressure above a predetermined threshold, or a "head" occurs). When this valve is closed the system then operates, conventionally, and for irrigation systems to eject water from water dispensing nozzles or spray heads located at or in proximity to the ground surface so that irrigation can take place. With this novel valve, the periodic (or annual) need to purge the irrigation system of residual water to clean out contaminants or to prevent winter freeze-up is avoided, since self-purging of the residual water and of any water suspended solids in the network takes place each time the water pressure in the system is reduced to approximately zero (or to below the said predetermined threshold pressure), as on each occurance of water shut off.

Abstract: A land drainage system comprising sub-soil tubes (1) connected to a suction container (3) has the container evacuated by a dual function system comprising liquid pumping means (4) and air extracting means (6). A reservoir (5) can contain liquid to be passed into the soil (e.g. for irrigating the land).

Abstract: A plant watering system for flower pots, plant boxes or open fields which uses watering cylinders located adjacent to the plant roots with the watering cylinders connected to a water supply unit through a closed pipeline system with the water supply unit maintaining a constant level of irrigation water. Moistening of the soil in the region of the watering cylinders permits the inherent suction intensity of the soil to suck water from the reservoir to the plant root when the available water in the soil is low and to not suck water from the reservoir when there is adequate moisture in the soil. The watering cylinders having means to prevent growth of roots therein while permitting water to be discharged to the surrounding soil.

Abstract: In association with a subsurface drainage/irrigation tile system, a head control stand is provided to selectively control the flow of water through a drainage/irrigation tile system and in turn control the depth of the water table. An actuating unit which includes a water level sensor floating on the surface of the water table is disposed within a riser pipe which extends upward from a subsurface drainage tile. A valve disposed within the drainage tile is connected to the water level sensor and opens upon the sensor raising in response to a raising in the water table which allows water to flow through the valve and subsequently closes the valve upon lowering of the water table.

Abstract: The present invention relates to a water detection subassembly and method for forming same, for use in association with water detection system operating within a digital computing center. The subassembly includes a perforated protective semi-circular shield fitted about a fabric mesh supporting copper conductors connected to a low voltage source. The perforations of the shield are formed into two distinct patterns: The first series comprises sets of openings adjacent to the apex of the shield and periodically spaced therealong. Each opening has a common arcuate length L, a width W, and an internal spacing S and, more importantly, is of sufficient dimension to allow easy entry of aerosol mixtures of air and water droplets originating from above the shield.

Abstract: An underground structure formed of rock and cinders permits an artificial water table to be maintained at a selected distance below the ground level. The installation includes a watertight membrane that lines a basin excavated in the earth. A ballast layer of generally uniform size rock is laid on top of the watertight membrane in the basin, and the ballast layer is extremely permeable by water. The ballast layer is covered by a permeable membrane such as cloth. The permeable membrane is, in turn, covered by a layer of finely divided particles such as crushed volcanic ash or cinders. The particles of this fine layer are prevented from penetrating the ballast layer by the permeable membrane. The fine layer permits water to diffuse through it by capillary action. The fine layer is topped by a finish layer which is appropriate to the use to be made of the installation.

Abstract: The present invention relates to a water detection subassembly and method for forming same, for use in association with water detection system operating within a digital computing center. The subassembly includes a perforated protective shield fitted about a fabric mesh supporting copper conductors connected to a low voltage service. In that way, the shield completely isolates the fabric mesh and copper conductors against abuse such as provided from workmen's shoes coming into contact with the subassembly during repair, replacement or renovation of computing equipment at the center.The shields are conveniently formed from commercially available plastic pipe such as PVC, sliced longitudinally and then attached to the concrete sub-floor of the computing room along the two cut longitudinal surfaces. Since a pair of shields can be formed from each section of plastic pipe, the shields are inexpensive to manufacture.

Abstract: A control method for an open channel for obtaining a stable condition of flow of water by coping with a transient change therein, comprising the steps of representing each space divided by gates of the open channel by a three water tank model including three imaginary water tanks in series and two imaginary conduits connecting the imaginary water tanks with each other; solving this model so as to obtain estimated future values of parameters of a state of the open channel; and determining a degree of opening of each gate so as to keep a liquid level of the space constant on the basis of the estimated future values of the parameters.

Abstract: A flow compensated controller for use in automatically controlling the water level in an open channel is disclosed. An electrical signal received from a transducer at a measuring location and corresponding to the actual water level in the channel at that location is amplified and compared with an amplified signal corresponding to the desired water level. An error signal corresponding to the difference between the two signals is fed into a proportional amplifier and also into an automatic reset unit. The outputs of the proportional amplifier and the automatic reset unit are fed into a summing amplifier. The output of the summing amplifier is fed into a motor modulation driver whose output is connected to a pair of gate operator relays, one relay connected for sending a control signal to the gate operator to move the gate in one direction and the other relay connected for sending a control signal to the gate operator to move the gate in the other direction.

Abstract: An improved irrigation system. The irrigation system includes a primary canal, a secondary canal having enclosed ends such that a flow of water entering the secondary canal accumulates therein and eventually overflows unless a sufficient volume of water is removed from the secondary canal, a water metering unit for diverting water from the primary canal to the secondary canal, siphons for transferring water from the secondary canal to a field adjacent the canal, and apparatus for monitoring the level of water in the secondary canal and activating an alarm when water in the secondary canal rises past a selected level.

Abstract: A synthetic surface, such as artificial turf, rubberized asphalt, concrete composition, particulate mixtures and the like, is applied on top of a subsurface base system, which in turn is on top of a subgrade. A liquid impervious membrane is positioned between the subgrade and the base system. The base system comprises an upper layer of sand-containing particulate material in which liquid characteristically moves in the vertical direction and a lower layer of gravel in which liquid characteristically moves well in the horizontal direction as well as downwardly. The material of the upper layer does not significantly penetrate into the gravel. The base system has a non-rutting upper surface. The non-rutting surface is accomplished by planting grass, cutting the grass at least once, and then killing the grass. The synthetic surface is then applied. A conduit system is positioned in the lower gravel layer of the base system, and a water reservoir is established in the base system.

Abstract: An irrigation system in which a main channel is connected to a series of irrigation bays by separate distribution channels and the flow of water to each bay is controlled centrally in response to the moisture content in each bay. The bays are irrigated in sequence by a central control system.