Patent Publication Number: US-6338595-B1

Title: Storm water control header for culverts

Description:
FIELD OF THE INVENTION 
     The present invention relates to a header intended for installation into culverts, water conduits, and watercourses for the purpose of restricting and controlling the flow of storm water in ditches, swales and other watercourses. 
     BACKGROUND OF THE INVENTION 
     During rainstorm events, and as a result of snow-melt, runoff water is directed into swales ditches and other conduits including storm sewers, and conducted in a largely uncontrolled manner to watercourses, lakes and rivers. In severe storms this can result large volumes of water moving at high velocities which can, in many instances, erode watercourses, and river banks, and damage culverts, roads and driveways, as well as carry contaminants from the watershed with deleterious results to the environment. 
     In undeveloped areas, interception and infiltration often retains much of the initial rainfall, but in developed areas, where the surface is largely impervious, or in situations where the ground has reached maximum saturation, or is frozen, the rapid rate of runoff can have extreme results, degrading water quality and damaging sewer infrastructure. 
     A system or device which will capture and detain high volumes of initial runoff for later release at a controlled rate into the drainage system, will delay and reduce water flow volume and velocity, protecting the infrastructure and the natural watercourses from physical and ecological damage. 
     The present invention provides for this control in a simple and effective manner, and functions without moving parts and little if any maintenance requirement. 
     SUMMARY OF THE INVENTION 
     In accordance with the present invention, a control header for culverts comprises a head-wall having an opening on the downstream face which is sized to match the diameter of the culvert, attached wing-walls, extending away from the head-wall on opposite sides thereof, and an adjustable inlet control device for regulating the flow through the opening into the culvert. Preferably the wing-walls are hinged to the head-wall, permitting the header to adapt to a variety of applications. 
     The above structure prevents erosion and damage to culverts and driveways overhead, and adjacent to the ditch or swale served by the culvert, as well as downstream watercourses of all types. The adjustable inlet is provided with screening means to facilitate the removal of trash and floatable solids by limiting their passage through drainage systems and into watercourses. Moderation of the velocity and volume of water flowing in the ditch reduces erosion in receiving watercourses thereby reducing erosion and undermining of banks. First flush water is detained which allows precipitation of suspended solids and improved water quality. Extended detention of storm-water aids in groundwater recharge and augmenting downstream base flow. Erosion and heaving of road and driveway crossings is achieved by controlling piping and saturation of bedding materials. Safety of individuals and animals is enhanced by providing means for their escape or removal at each header location. The esthetic appearance of an integrated head-wall and wing-wall assembly creates a clean image. 
     When used in a linked system, with applicant&#39;s headers installed in series at multiple culvert locations, the combined upstream storage capacity can provide both water quality and quantity benefits and minimize requirements for “end of pipe” pond facilities that are expensive and generally require the use of otherwise utilizable land. 
     In accordance with the present invention, the header can be manufactured from non-corrosive plastic or ferrous materials, and is compact in form to facilitate low cost packaging and shipping. Designed for assembly in the field, flexibility is provided since the header can be easily adjusted to suit a variety of installation requirements, various construction materials and situations. By means of knock outs the “low flow rate of the header can be adjusted to detain large volumes of rainwater, providing slow release into the system at a controlled rate. 
     The header includes an overflow weir which provides for the exact and specific control of the water levels retained at each culvert location, while allowing for passage of large volumes of water once the upstream storage area has reached maximum volume, or in extreme runoff events. 
     The header is so designed that a single stock-keeping unit can be used for and installed in a multiplicity of culvert sizes, thus simplifying inventory control and reducing inventory units and management. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective of the header of the present invention, 
     FIG. 2 is a section of a ditch showing the culvert header installed in the ditch, 
     FIG. 3 is a perspective of the adjustable inlet control device, 
     FIG. 4 is an exploded view of the components of the control device of FIG. 3, 
     FIG. 5 is a perspective view of the head-wall or flat plate of the header, 
     FIG. 6 is a perspective view of the downstream side of the plate of Figure, and 
     FIG. 7 is a perspective of a wing-wall attachable to the head-wall 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to FIG. 1 there is shown a culvert or conduit header of the present invention consisting of a head-wall  10  in the form of a flat plate, with an adjustable inlet control device  11  mounted on the upstream face and a thimble  13  (FIG. 6) on the downstream face thereof. Detachable wing-walls  12  are shown mounted on either side of the head-wall  10 . 
     As shown in FIG. 2, the header is installed in a substantially vertical position with the adjustable inlet device  11  on the upstream side of the head-wall  10 , and with the thimble  13  inserted in the upstream end of the culvert  20 . Conventionally, the wing-walls  12  are positioned either side of the head-wall  10 , with the free ends of the wing-walls upstream of the head-wall  10 . Aggregate  21  is placed on top of the culvert  20  and behind the header, and a driveway  30  is constructed on the aggregate  21 . 
     During a heavy rainstorm, such as a thunder shower, rapid flow of water through the ditch  25  is impeded by the header holding back water  40  upstream of the head-wall  10 , which is released by the adjustable inlet control device  11 . The thimble  13  is of the same size and shape as the culvert, having an outside circumference the same as the inside circumference of the culvert, and is shown in greater detail in FIG. 6 hereof. 
     FIG. 3 is a perspective view of the adjustable inlet control device  11  mounted on the head-wall  10 . FIG. 4 is an exploded view of the inlet control device  11 . The control device  11  consists of a base section  14 , an upper wall section  15 , and a cover section  16 . The base section  14  is provided with openings  17  and knockouts  18 , which may be removed in sufficient number so as to permit the passage of volumes of water that are less than, or at maximum not in excess of the flow of water during the average occasion rainfall experienced in the area of installation. Flows greater than this such as are encountered during a storm event are restrained and slowly released at a moderate flow rate over an extended period of time. The flow moderation, and slow release of the large volumes of water substantially reduces the risk of washout of culverts, and the risk of overloading downstream flow channels, and consequent damage to the drainage system, and risk of pollution from such damage. 
     The upper wall section  15  of the inlet device  11  is designed so that it can be installed and adjusted to various heights so that it will detain volumes of water upstream of the header  10 , to a level that is relevant to the topography of the installation. In order to accomplish this, the top edge  19  of the upper wall section  15  is designed to form a weir. Recessed grooves  19 A may be embossed below the rim  19  of the upper wall section  15 , to provide guides to assist in and facilitate cutting or removal of the rim  19  of the upper wall section  15  so as to further refine the height of the weir section. 
     The cover  16  is an optional section designed to prevent the flow of debris or floatables into the inlet device  11  and to the culvert  20 . The width and length of the inlet device  11  are so designed that the cross-sectional area of the inlet device is approximately equivalent to the area of the largest culvert or conduit into which the spillover water will be released in order to provide unimpeded flow of water in extreme storm events. 
     Referring to FIGS. 5 and 6, the head-wall  10  is shown in upstream and downstream views respectively. In FIG. 6 a plurality of thimbles  13  are shown, which may be used for connection to a plurality of different sizes of culvert. These thimbles  13  are arranged eccentrically so that the thimble selected will be as low on the head-wall  10  as possible. Indentations  10 A molded into or scribed on the upstream face of the head-wall opposite the thimbles are provided as guides to assist in cutting out portions of the head-wall  10  in order to provide the opening required for the culvert, by removal of thimbles  13  which are smaller than that required for the installation of the correct size of culvert header thimble  13  into the culvert  20 . Reinforcing ribs may also be molded into the downstream side of the head-wall  10 . The side walls may be similarly strengthened, as required. 
     The vertical edges  10 C and  10 D are designed with tabs C and D for interlocking the head-wall  10  to the sidewalls  12  by inserting a pipe or re-bar through the tabs of the vertical edges of the adjoining walls. The top edge and lower edge of the head-wall, may be formed so as to provide purchase for construction materials that may be installed to retain grade above or below the edge of the walls. The preferred material for forming the control header of the invention is polyvinyl chloride (PVC) although other materials may be selected for specific applications or locations. Strength requirements are not high since the material backfilled against the downstream side of the header resists the forces of the water against the upstream side of the header. 
     Persons understanding the invention will appreciate that variations in the construction of the header may be made that will fall within the scope of the appended claims.