Patent Publication Number: US-2021180306-A1

Title: Methods and systems for an adaptable temporary inlet protection assembly

Description:
TECHNICAL FIELD 
     The present invention relates in general to devices for filtering silt and debris from collecting in storm water drainage pipes at construction sites; and in particular to filtration devices configured to enclose an open end of a drainage inlet of a storm water drain system and trap and prevent silt and other debris from being washed into or otherwise being deposited within the of the storm water drainage system, while still enabling water to pass into the inlet. 
     BACKGROUND 
     In the construction of residential and other types of developments, the road system generally is first marked out and the streets into and through the development are cut and graded. Thereafter, the storm water drainage system for the development is constructed, typically including underground drainage pipes, collection boxes and culverts, and inlets that form the manholes or drain openings along the street. The inlets generally can include cylindrical concrete pipes that are installed vertically, but can also include square or V-grate type inlets, and/or other types or configurations. The lower ends of the inlets will connect to the collection boxes and the drainage pipes of the storm water drainage system, with their upper ends being substantially at or above street level. 
     During the construction of roads and drainage systems, until the street has been substantially completed, the drainage pipes and inlets must be kept substantially free of dirt and debris pursuant to state and county building codes. Keeping dirt and debris out of the drainage system is, however, very difficult to accomplish as during grading of the roads and curbs, as well as additional grading on site, dirt and debris typically is pushed to the sides of the street by the motor grader or bulldozer, and thus may pass into the upper ends of the inlets. In addition, rain, runoff and wind also tend to wash or blow dirt and debris into the open ends of the inlets, which will then collect in the collection boxes and sewer pipes. 
     Devices such as the Silt Saver® filter assembly have been developed to provide a system for temporarily protecting and preventing dirt and debris from enter the drainage pipes. Such devices have been effective in preventing dirt and debris from entering drop inlets and other, similar drainage pipes. However, drainage inlets and other, similar devices needing protection can vary in size and shape, particularly as new uses and new drainage structures are developed, and it is important for filter assemblies or structures for filtering silt for runoff water to be securely mountable to such newer and various existing inlet designs, so that silt and debris can be substantially filtered from runoff water flows and to guard against collapse or shifting of the filter assembly during high winds or other weather conditions. 
     Accordingly, a need exists for a silt retention and filter assembly that can remove silt, dirt, and debris from runoff water flows and prevent such materials being washed or blown into a stormwater drainage system, and that addresses the foregoing and other problems in the art. 
     SUMMARY 
     Briefly described, the present disclosure is, in one aspect, directed to methods and systems for providing a temporary and substantially rigid silt retention assembly for protection of drainage openings or inlets of storm water drainage systems from ingress of silt and debris. The silt retention assembly of the present disclosure generally is designed for use at construction sites for enclosing the open upper end of inlets, such as a drop inlet, a V-grate type inlet, or other drainage opening or inlet of a storm drainage water system, for example, during the construction of the streets, curbs, and the construction of the drainage system itself. The silt retention assembly includes a silt retention device having a body that can be substantially generally cylindrically shaped, although other shapes/configurations also can be used, and a base for mounting the silt retention device over an inlet of the storm water drainage system. The silt retention device typically can be formed from a rigid, durable plastic material, although other materials, and various shapes and/or sizes may be envisioned for the silt retention device. 
     In one embodiment, the body of the silt retention device can include an upper end and a lower end, with a series of spaced, vertically extending slats or ribs or other frame structure extending therebetween. Flow passages will be formed in the body for passage of water; for example, the slats can be spaced from one another to define a series of spaced openings or passages that enable the flow of water through the silt retention device while blocking passage of large debris, dirt and silt. The silt retention device further can include a top portion at the upper end of the body, which can be substantially flat, curved or dome shaped, and also can include radially spaced slots or openings to provide extra pathways for storm runoff to drain into the inlet. In other embodiments, the top portion can be substantially solid, open, or can be formed a pivotable or removable cover or lid to enable further access therethrough. 
     The base plate of the temporary silt retention assembly can be formed with or can be attached to the lower end of the silt retention device. In some embodiments, the base plate extends outwardly from the lower end of the silt retention device. In other embodiments, a bottom rim can be formed about the lower end of the body, slightly overlapping the sides of the body, and can function similar to and/or in place of the base plate. The bottom rim or base plate can project radially outwardly from the body, and it will be understood that the rim or base plate can be formed in various configurations, can be flat or with a slope, and may be integrated/formed with the silt retention device body or separately formed and attached to the lower end of the silt retention device via suitable fasteners. 
     The temporary silt retention assembly further will include an adapter that can engage and attach to the base plate or the bottom rim at the lower end of the body. The adapter generally will include a frame configured to be mountable to and be substantially co-extensive with the base plate or bottom rim along one or more sides thereof. The adapter further can include foldable or extensible cover features configured to provide an extension of the filtering structure of the temporary silt retention assembly. The cover feature generally will be flexible and sized/configured to substantially overlap and/or cover gaps or other exposed areas between the inlet structure such as to drop inlet or a V-shaped grate inlet, and silt retention device and can help seat and secure the silt retention assembly over the inlet structure. The adapter thus can extend the protective coverage of the temporary silt retention assembly to peripheral or other portions of the inlet to enclose and/or substantially block additional open areas or portions of the inlet not directly covered by the silt retention device body and/or base plate/rim, enabling the silt retention assembly to be used with and accommodate a wide range of varying size and/or configuration inlets. In addition, slots or openings also can be formed in the foldable cover feature to provide extra pathways for stormwater runoff to drain into the inlet. 
     In one embodiment, the adapter may be separately formed, with a configuration that fits selected size(s) or a range of sizes of drainage inlets or other structures. The adapter then can be attached in the field to the base plate or to the bottom rim of the silt retention device via a fitted engagement therewith or by use of suitable fasteners or other connectors. The adapter, base plate and the silt retention device body also may be formed as a single structure in a molding process, and in some embodiments, the base plate or bottom rim may not be required and the adapter may be directly attached to or formed with the silt retention device body. In still another embodiment, the base plate or rim and/or the silt retention device may be attached to the adapter component via a releasable locking mechanism formed or otherwise provided in the base plate, the silt retention device body, and/or the adapter. 
     In some implementations, such as when the adapter, the base plate, and the silt retention device are formed separately, the adapter may be transported to site in a generally folded flat arrangement. The adapter can be initially seated on the drainage structure, with its foldable cover feature released and extended/seated over and secured about the inlet structure. The base plate or rim and the silt retention device body then can be fitted over the adapter, secured in place with the adapter being seated and supported thereon. If further desired or as needed, the baseplate and silt retention device can be locked in place via fasteners or other connector mechanisms. 
     The components of the silt retention assembly, including the silt retention device, the base plate, and the adapter can be constructed from a substantially rigid, durable plastic material such as Polyvinylchloride (PVC), acrylonitrile-butadiene-styrene (ABS), high density polyethylene (HDPE), high molecular weight polyethylene (HMWPE), or an acetyl resin such as “DELRIN”, or any other similar rigid, durable, high strength materials, including metals such as aluminum, that are relatively lightweight for ease of handling. The components of the silt retention assembly further generally can be constructed by a molding process, including, for example, injection molding, rotational molding, blow molding, compression molding, extrusion molding, or thermoforming. 
     The molding process for the construction of the silt retention assembly, in one aspect, can include forming an initial mold of the silt retention device body of the silt retention assembly, with the base plates or rim portions and the adapters being formed in separate molds based on size and/or configuration needed. The base plate and adapter thereafter can be selected based on the size/configuration of the inlet(s) for which the silt retention assembly is to be used and separately transported and mounted to the silt retention device body in the field. 
     In other embodiments, the mold(s) for the components of the silt retention assembly can be integrated, either as a single mold, or may include provisions to selectively mount varying molds for the base plate and/or adapter portions to a mold for the silt retention device body, so that the base plate or rim, and/or the adapter components can be molded together as a single or substantially unitary structure. For example, molds for a base plate and/or an adapter having configurations based on an application to various inlet configurations can be selected and coupled to a mold for the silt retention device body, and thus molded with the silt retention device body to form a substantially integrated structure including the base plate/rim and adapter as part of the silt retention device body. Thus, a standardized mold can be used for the silt retention device body design, and can be customized to incorporate various base plate and/or adapter designs suitable for application in a wide variety of inlet configurations. 
     In use, a filter material formed from a silt screen, mesh or similar porous filtering material will be fitted over the silt retention assembly. The filter material generally can be sized and shaped to conform to the shape of the silt retention assembly typically being fitted over the top portion of the silt retention device body covering the slats thereof. For example, workers can wrap the body portion of the silt retention device with a silt screen or other filter material in place of the filter cap or cover. The silt screen material can be secured to the upper end of the silt retention device body, such as by fasteners, tape, or on hooks or similar fastening devices mounted to the body. The lower end of the silt screen material can be left overlapping the bottom portion of the silt retention device, the base plate or bottom rim, and the adapter, by a length selected to overlap the upper end of a drainage structure on which the silt retention assembly is mounted. 
     In some embodiments, the filter material can be formed as a cover or cap that also can be formed with or have attached thereto, a skirt portion that overlaps the bottom rim of the silt retention device, the base plate and/or the adapter. The top portion of the filtering material also can be painted or dyed a fluorescent color to make it easier to detect to warn of or signal the location of the inlet structure that is covered by the silt retention assembly. A ring or support tube also can be applied at the bottom of the cover (i.e. along the skirt portion), and can define a pocket or series of pockets about the bottom of the skirt portion, in which dirt and/or stones or other ballast materials can be placed to help hold the cover in place. 
     As dirt impounds against the silt retention device and adapter, the weight of the dirt further helps hold the silt retention device body on the inlet and hold the filter material against the silt retention device and adapter. The slats or ribs of the silt retention device body and the adapter provide strength and a substantially rigid support to the silt screen material against dirt and debris carried with stormwater flows so as to prevent the collapse of the silt screen material, thus blocking the passage of the dirt and debris into the drop inlet, while enabling rain and runoff water to pass therethrough and into the stormwater drainage system. 
     Once the curbs have been graded and are being poured, workers can dig out excess dirt from around the silt retention assembly and the inlet, and the silt retention assembly can be lifted upward and off of the drop inlet to enable a throat to be poured around the inlet to finish the drain or manhole. The filter material also will be removed from the silt retention device and adapter, which then can be cleaned of excess dirt and debris, leaving them ready for a next use. 
     Various objects, features and advantages of the present invention will become apparent to those skilled in the art upon a review of the following detail description, when taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       It will be appreciated that for simplicity and clarity of illustration, elements illustrated in the Figures are not necessarily drawn to scale. For example, the dimensions of some elements may be exaggerated relative to other elements. Embodiments incorporating teachings of the present disclosure are shown and described with respect to the drawings herein, in which: 
         FIG. 1  is a perspective view illustrating the mounting of a silt retention assembly over the upper end of an inlet for a drainage system; 
         FIG. 2  is a perspective view illustrating configuration of a V-shaped grate inlet for a drainage system for which a silt retention assembly may be adapted; 
         FIG. 3  is a perspective view illustrating a silt retention device body and base plate or rim of the silt retention assembly, according to an embodiment of the disclosure; 
         FIG. 4  is a perspective view illustrating an adapter for use as part of the silt retention assembly, according to an embodiment of the disclosure; 
         FIG. 5  is a perspective view illustrating installation of the adapter and retractable features of the silt retention assembly on a V-shaped grate inlet, according to an embodiment of the disclosure; 
         FIG. 6  is a perspective view illustrating another embodiment of the silt retention device body and the adapter with retractable features of the silt retention assembly, according to an embodiment of the disclosure; 
         FIGS. 7A and 7B  illustrate example geometries of the silt retention device body, the base plate, and the adapter of the silt retention assembly, according to an embodiment of the disclosure; 
         FIGS. 8A and 8B  illustrate example geometries of the silt retention device body, the base plate or rim, and the adapter of the silt retention assembly, according to an embodiment of the disclosure; 
         FIGS. 9A and 9B  illustrate additional example geometries of the silt retention device body, the base plate or rim, and the adapter of the silt retention assembly, according to an embodiment of the disclosure; 
         FIGS. 10A and 10B  illustrate still further example geometries of the silt retention device body, the base plate or rim, and the adapter of the silt retention assembly, according to an embodiment of the disclosure; 
         FIG. 11  is a perspective view illustrating the mounting of the silt retention assembly with a filter cover over an inlet for a sewer or drainage system; 
     
    
    
     The use of the same reference symbols in different drawings indicates similar or identical items. 
     DETAILED DESCRIPTION 
     The following description, taken in combination with the Figures is provided to assist in understanding the teachings disclosed herein. The description is focused on specific implementations and embodiments of the teachings, and is provided to assist in describing the teachings. This focus should not be interpreted as a limitation on the scope or applicability of the teachings. 
     In general, the present disclosure is directed to systems and methods for a temporary and substantially rigid silt retention assembly for inlets used in storm water drainage systems. The silt retention assembly of the present disclosure can be installed can be adapted to be used with a variety of inlets associated with storm water drainage systems, including ones with substantially complex and/or non-flat geometry. Some of the embodiments of the present disclosure contain molding processes to achieve flexible designs of the silt retention assembly. 
     Referring now to the drawings in which like reference numerals indicate like parts throughout the several views,  FIG. 1  illustrates a temporary silt retention assembly  10  according to principles of the present disclosure mounted over a V-grate inlet  11  of a storm water drainage system (not shown). The silt retention assembly  10  generally is designed as temporary but stable system for covering and protecting a drainage inlet such as a drop or curb or gutter inlet of a storm water drainage system from ingress of silt, debris, etc. . . . , such as during grading and construction of roadways, can be used with a variety of different type, size and/or configuration structures as well as during site grading of new residential or commercial constructions. The silt retention system will block silt and debris from collecting within the underground pipes of the storm water drainage system while enabling drainage of filtered run-off water into and through the storm water drainage system. Typically, the storm water drainage system will include underground concrete or metal drainage pipes, and/or collection boxes (not illustrated), with inlets, such as a drop inlet, or other types of drainage inlets  11 , mounted thereto. As illustrated in the figures, the silt retention assembly  10  is designed to be adaptable to securely seat upon and be used with drainage inlets or similar structures having a variety of different configurations and/or sizes, including ovals, square, rectangular, V-shaped, or other configurations. 
     By way of example only,  FIGS. 1-2  illustrate a drainage inlet  11  shown as a V-grate or type J inlet having substantially wedge or V-shaped ( FIG. 2 ) profile/construction and typically formed from concrete or similar material. The inlet  11  will have a body  12  with an open lower end  14  that generally will connect to a drainage duct or pipe (not shown) and an upper end  16  shown in  FIG. 2  as including inwardly/downwardly sloped portions  17 . The sloped portions  17  can have slots or openings defining grates  15  through which water drains into the storm water drainage system. To temporarily enclose and prevent dirt and debris from clogging the inlet, while still enabling storm runoff water to drain into the drainage system, the temporary silt retention assembly  10  of the present invention will be mounted on the upper end  16  of the inlet  11 , as illustrated in  FIG. 1 . It further will be understood that while a V-grate type of drainage inlet is illustrated for discussion within the present disclosure, other types, sizes and/or configurations of drainage inlets, including inlets or drainage structures/pipes with irregular surfaces and shapes, including non-flat surfaces, also can be protected using the silt retention assembly according to the present disclosure. 
     The silt retention assembly  10  of  FIG. 1  includes a silt retention device  100  having a body  101 , a base plate or bottom rim  102 , and an adapter  103 . The silt retention assembly  10  also may be formed with the silt retention device  100  and the adapter  103 , without a base plate. As further indicated with reference to  FIGS. 1 and 3 , in one embodiment, the body  101  of the silt retention device  100  can be generally substantially cylindrical in shape and approximately one to about three-four feet in height, although other shapes and sizes also may be envisioned. The size of the silt retention device further can be selected based on a size of the inlet or other component of the stormwater drainage system to be covered and protected, and further generally will be of a size selected or as needed to extend above the upper end  16  of the inlet  11  sufficient to enable water to pass therethrough as silt piles up against it, and to provide a visual indication or marker of the location of the inlet  11 . 
       FIG. 1  shows the silt retention assembly  10  and the silt retention device  100  fitted over and seated upon the upper end  16  of inlet  11 , but as indicated, the V-shape of the inlet creates open areas  15  on at least 2-sides thereof that are not enclosed by the silt retention device body  101  and base plate  102 . The adapter  103  extends the coverage of the silt retention assembly to overlap and cover such areas  15  and substantially eliminate such gaps in coverage through which silt, dust, debris can pass. As further indicated in  FIGS. 1 and 5-10 , the components of the silt retention assembly  10  may be formed to fit different types and sizes of inlets. For example, the adapter  103  can be sized individually to fit different shapes and sizes of inlets, while the silt retention device  100  and/or the base plate  102  or rim thereof may have a standard size and/or configuration. The silt retention device and adapter  103  accordingly can be easily configured/arranged to enable use of the temporary silt retention assembly and application to different types, configurations and sizes of drainage inlets  11 . 
     In addition, while  FIGS. 1 and 3  indicate that the silt retention device  100  and base plate  102  can be formed or integrated as a single unit or structure, i.e., with the base plate  102  formed as a component of the body  101 , the silt retention device  100  and base plate  102  also may be formed as separate components that can be assembled/attached together by way of a frictional or mating engagement, by fasteners, locking mechanisms, or other releasable connections. Similarly, though the adapter  103  is shown mounted or coupled to the base plate  102 , in some embodiments, it can be integrally formed with the base plate and/or the body of the silt retention device. 
     The components of the silt retention device, the base plate, and the adapter further typically can be molded, extruded or otherwise formed from a durable plastic material such as in the polyvinylchloride (PVC), acrylonitrile-butadiene-styrene (ABS), high density polyethylene (HDPE), high molecular weight polyethylene (HMWPE), or acetyl resin such as “DELRIN”, or any other similar rigid, durable, high strength materials, including metals such as aluminum, that are relatively lightweight for ease of handling. The silt retention device also generally will have an internal passage  21  ( FIG. 3 ) defined therethrough and along which storm runoff water passes and drains into the inlet  11 , and thus into the storm water drainage system of the development. 
     As shown in  FIG. 3 , the body  101  of the silt retention device  100  includes a lower portion  110  and a top portion  111 , and typically will be formed as a unitary structure. In some embodiments, the body  101  of the silt retention device  100  can be approximately 18 to 28 inches in height (though other heights can be used), with an open lower, first or bottom end  112  and defined in the bottom portion  110  and an upper or second end  113  at its top portion  111 . As  FIG. 3  indicates, in some embodiments, the body portion can be substantially tubular or cylindrical that can be closed or provided with an opening and can be tapered or slightly inclined from lower end toward upper end in order to enable additional silt retention devices to be stacked thereon for ease of storage and transport. The body further can include a spaced series of elongate slats or ribs  114 , extending between the upper and lower ends and of the body, and defining radially spaced openings  116  or passages therebetween. The slats and the passages therebetween can be formed with various dimensions (e.g. between approximately ½″-4″) as needed to enable water to drain through the body portion and into an internal passage of the silt retention device. It also will be understood that the dimensions of slats, and of openings/passages may be varied in accordance with the needs of the users of the silt retention device to provide larger or smaller passages. For example, larger slots or openings having various configurations such as rectangular or triangular can be used to provide larger open areas such as at the upper ends of the passages as needed or desired. 
     As also illustrated in  FIGS. 1 and 3 , the top portion  111  of the silt retention device  100  can have a reduced diameter compared to the diameter of the lower portion of the body, and can be slightly curved or arched, forming a curved or domed top end  113 , although it can be flat if so desired. The top portion covers or encloses the silt retention device body and also can be reinforced to support added weight. A series of radially spaced slots or upper openings  115  also can be formed in the top portion, for example, formed as elongated, substantially rectangularly shaped openings that extend at least partially across the top portion and provide additional passageways for overflow storm runoff into the drop inlet, when and as needed. A single, substantially centrally located opening also can be used in place of or in conjunction with the slots, and/or a removable door or cover also can be provided. In addition, the slots also can enable a pipe or bar to be inserted therethrough to provide a means by which the silt retention device can be lifted upwardly off of the drop inlet after use, i.e., after project completion. 
     Referring again to  FIG. 1 , in some embodiments, the base plate  102  of the silt retention assembly  10  can be formed about or attached to the lower end of the silt retention device body  101  to provide a platform for covering and seating the silt retention device over/on the inlet or other drainage structure. The base plate  102  generally will have an upper surface  121  that can be flat or slightly sloped, and a lower surface  122  with a rim or peripheral edge  123  configured to align with and receive the adapter  103  in a substantially mating or seating engagement therewith. It also will be understood that the base plate  102  can be formed with a substantially flat and/or other configurations. The base plate  102  also generally will have a thickness sufficient to provide stability and weight to the silt retention device when seated on an inlet. For example, it can have a thickness of approximately 1 to 4 inches, although other thicknesses also can be used. The shape and outer dimensions of the base plate  102  further can be selected based upon the configuration of the adapter  103 , as well as the configuration of the type and shape of inlet  11  over which the silt retention assembly  10  is mounted. 
     By way of example, in  FIGS. 1 and 3 , the base plate is shown with a substantially square footprint or shape that projects from the lower portion of the body of the silt retention device  100 , i.e. by about 3 to 12 inches, and is adaptable to fit directly over inlets or other drainage structures of various sizes and constructions, and/or to engage with various configuration adapters. In addition, although the base plate illustrated in  FIGS. 1 and 3  is shown with a substantially square configuration, and extending out from the lower portion of the body it is possible for the base plate to be formed in other configurations or shapes, such as with a rectangular shape, or a circular bottom rim that can be flared outwardly or otherwise configured to receive and engage or be coupled with the adapter. 
     Referring again to  FIG. 1 , the adapter  103  of the silt retention assembly  103  is configured to attach or otherwise engage with to the base plate  102  or directly with the lower portion of the silt retention device body  101 . As further illustrated in  FIG. 4 , in one embodiment, the adapter  103  will have a frame portion  104  that can be configured and/or sized so as to be substantially co-extensive with the base plate  102  such that the base plate can be received and at least partially seated thereon. The adapter  103  further can include one or more flexible, foldable or extendable cover features  105 . 
     The base frame  104  of  FIG. 4  can be made of wood, but may be constructed out of a variety of materials, including polyvinylchloride (PVC), acrylonitrile-butadiene-styrene (ABS), HDPE, high molecular weight polyethylene (HMWPE), or acetyl resin, such as “DELRIN”, or any other similar rigid, durable, high strength materials, including metals or alloys such as aluminum or stainless steel and can be constructed by attachment of frame members  104 A- 104 D, such as by fasteners, adhesives, by welding or molding the frame as a unitary structure. The base frame  104  can include reinforcement members  106  to substantially support the base plate  102  and the silt retention device  101 . The base frame  104  also may include grooves or connecting/locking features  107  adapted to engage and/or couple the adapter to the base plate  102  or to the silt retention device body  101  (for example as shown in  FIGS. 7A-10B ). Furthermore, the base frame  104  can have braces or supports  108  and generally will include an opening  109  that substantially aligns with the bottom opening of the silt retention device  100  and the openings  15  of the inlet structure  11  for passage of water therethrough. 
     As also noted, the shape and configuration of the base frame  104  can be constructed to match the configuration of the inlet  11 , and can be modified, i.e., the frame members can be extensible or can be constructed in sections or connectable pieces to enable the adapter to be assembled and fitted to the inlet structure with the silt retention device seated thereover as needed in the field. As illustrated in  FIG. 5 , the dimensions of the base frame  104  thus can be sized to coincide with the perimeter of the inlet structure  11 , or can be constructed in sections to enable the adapter to be assembled and fitted to the inlet structure as needed in the field. In addition, while the frame  104  is shown in the figures as being made of wood in one embodiment, other materials, such as metal or plastic/composite materials also can be used. 
     Referring to  FIGS. 4 and 5 , the cover feature  105  can be attached to the base frame  104  via fasteners  117 , adhesives, etc., or can be formed with the base frame  104  (i.e., by extrusion, welding, etc.). The cover feature generally will include a body  203  that will be flexible or foldable such that the cover feature(s)  105  can be folded substantially flat and flush with the base frame  104  for ease of transportation. Similar to the silt retention device  101 , the foldable feature  105  also can include slats  118  defining openings  119  to enable water to drain through the foldable feature  105  and into the inlet structure  11 . It will be understood that the dimensions of slots, openings or passages may be varied in accordance with the uses of the silt retention assembly  10 , e.g., to provide larger or smaller passages depending on projected water flows such that varying size slots or slots having various configurations such as rectangular, triangular, U-shaped, and so on, can be used as desired. In an embodiment, the foldable feature  105  may slant outwardly away from inlet structure  11  or can be formed with a curved construction. 
     During installation, as shown in  FIGS. 1, 5 and 6 , the foldable feature  105  can be moved or unfurled from its flat position into a position to overlap/abut the outside edges of the inlet structure  11  so as to cover and substantially enclose portions of the inlet/drainage structure not covered by the silt retention device and through which silt, dirt and debris could potentially pass. With the foldable feature  105  on two or four sides of the base frame  104 , the adapter  103  may be substantially secured around and enclose the inlet structure  11 . 
     Referring now to  FIG. 6 , in an embodiment, a silt retention device  100  can be provided with a body  201  configured to be installed directly over the adapter  103  without a base plate. The silt retention device body  201  of  FIG. 6  may be configured with a different configuration of slots or openings than the slits represented in  FIG. 1 , also may include a lip or bottom rim  204  that is formed about the lower portion. The adapter  103  of  FIG. 6  will include a cover feature  205  that may also have openings  206  and slats  207  (or other supports) configured differently than the slots indicated in  FIGS. 1 and 4-5 . Also, the cover feature  205  of  FIG. 6  may be configured to be foldable inwardly so as to be received within the inlet structure  11 , and engage an inner side wall thereof, which can help enclose the passage of the inlet and substantially secure the adapter within the inlet structure  11 . This may help reduce the size of the adapter. 
       FIGS. 7A-10B  illustrate various geometrical configurations of the silt retention system according to the principles of the present disclosure.  FIG. 7A  illustrates a silt retention assembly  702  with a silt retention device  704  having a circular configuration that can be adapted to fit over an inlet opening  705  of approximately 36″-48″ in diameter, although other shapes and greater or lesser sizes may be envisioned. The silt retention device  704  is shown as including or being attached to the base plate  706 , which in this case is of a square or rectangular configuration, and can have a substantially flat profile. The silt retention assembly of this embodiment will include an adapter  708  having a cover feature  710  (shown in the unfolded configuration in the partial cross-sectional view). The cover feature  710  of the adapter  708  is also shown with generally U-shaped slots  709  or openings enabling water to pass therethrough. 
       FIG. 7B  illustrates the silt retention device  704  with a generally circular configuration, but with a base plate  716  that has an elongated rectangular profile. The cross-sectional view illustrates that an adapter  720  is attached and extends along two sides to the inlet  718 , overlapping and covering/enclosing the sides of the inlet not enclosed by the silt retention device. 
     Referring now to  FIG. 8A , in another embodiment of the disclosure, a silt retention device  804  has a circular configuration attached to a base plate  806  of circular configuration. For example, the silt retention device  804  has a diameter of approximately 48 inches, while the base plate  806  has a diameter of approximately 60 inches. The base plate  806  also can be directly attached to the inlet  808 , without an adapter.  FIG. 8B  illustrates a cross-sectional profile of the embodiment illustrated in  FIG. 8A , wherein a silt retention device with a circular profile is attached to a base plate with a circular profile directly attached to the inlet  808 . 
       FIG. 9A , illustrates an arrangement of a silt retention assembly  900 , wherein the silt retention device  904  is of a circular configuration, connected directly to an adapter  906  of square configuration. As indicated in the partial cross-sectional view  910 , the adapter is attached to the inlet  908 . In  FIG. 9B , the silt retention device  914  has a circular profile and is connected to an adapter  916  of a rectangular configuration. Again, the adapter is shown as being connectable to the inlet  918  in the partial cross-sectional view of  FIG. 9B . 
     Referring to  FIG. 10A , a silt retention assembly  1002  is illustrated with a silt retention device  1004  having a circular configuration and directly connected to an inlet  1008  with a circular configuration without a base plate or an adapter, which is further illustrated in the partial cross-sectional profile  1010 . For example, the silt retention device  1004  may have a diameter of 48 inches, while the inlet may have a diameter of 24 inches. The silt retention device  1004  may include provisions to attached the silt retention device  1004  to the inlet  1008 .  FIG. 10B  illustrates another embodiment of the disclosure, wherein the silt retention device is attached to an inlet  1018  of square configuration. It should be noted that, in the embodiments illustrated with reference to  FIGS. 7A-10B , the silt retention device may be installed with a base plate or an adapter or both, or the silt retention device may be installed on its own. 
     Referring now to  FIG. 11 , in use, a filter material  30  is applied over and about the silt retention assembly  10  to filter silt and debris from storm water flows. The filter material generally is received over the silt retention assembly  10 , generally covering the silt retention device, the base plate and the adapter, and will formed from a porous filtering material, such as a polyester, polyolefin or polypropylene filter material, or a conventional silt screen or mesh material of the type known to those of skill in the art, and can also include a plastic, nylon, or wire mesh, or other similar filtering material or fabric. 
     As shown in  FIG. 11 , the filter material can be pre-formed as a cap or cover  35  sized and shaped to fit over the silt retention device with its lower edge  36  overlapping the adapter and base plate. Typically, the filter cap  35  will be cut or formed from sheets of the filtering material sewn together to form a skirt or body portion  37  and a top portion  38 , or otherwise attached in a configuration similar to that of the silt retention device, the base plate, and the adapter, so as to substantially match the profile of the silt retention assembly. It also would be possible to form the filter cap from a single sheet of filtering material sized and shaped to drape over and cover the silt retention device. 
     The top portion  38  of the filter cap generally will rest and be supported on the top portion of the silt retention device, with the silt screen material of the skirt or body portion  37  covering and being laterally supported by the slats of the body portion of the silt retention device. As also shown in  FIG. 11 , the lower edge  36  of the filtering material of the cover  35  is left overlapping the bottom rim of the silt retention device or the base plate or the adapter component by approximately 3 to 6 inches or more. The skirt of the filter cap at various spaced locations about its circumference defines an elongated, open-ended pocket or a series of pockets  41  spaced about the skirt of the filter cap  38 . Stone, dirt, sand, or similar filler material is placed within the pocket(s)  41  to provide additional weight and support for holding the filter cap  38  on the silt retention assembly to prevent the filter cap  38  from being dislodged from the silt retention assembly under high winds or excessive water run-off. Accordingly, once the silt retention assembly is installed over the upper end of an inlet  11 , the upper end of the inlet is likewise overlapped by the lower edge  36  of the filter cap as shown in  FIG. 11 . The filter cap will be held in place initially by stone and/or dirt placed by workers during the installation of the silt retention device and is further secured against the silt retention assembly by the silt and debris washed thereagainst and which the filter cap prevents from flowing into the drop inlet with the runoff or storm water passing through the silt retention device. 
     It is also possible to use a sheet or roll of conventional silt screen material that is wrapped about the silt retention device instead of using the pre-formed filter cap or cover  35  illustrated in  FIG. 11 . Such silt screen material can be rolled or wrapped about the body portion of the silt retention device  101  with its lower edge overlapping the bottom rim of the body portion or the base plate or the adapter by approximately 2 to 6 inches. The upper edge of the silt screen material typically will be secured to the top portion of the silt retention device by a series of fasteners such as screws or hooks, or other types of fastening devices including adhesives and metal bands or ties to secure the upper edge of the silt screen material to the silt retention device. 
     In addition, the top portion of the silt screen material or the filter cap can be dyed or painted with a fluorescent color, such as a bright orange or red, either at its center or in its entirety. This will make the filter cap and thus the silt retention assembly itself stand out more prominently and provide a clear and easy to recognize visual indicator of the existence and position of the drop inlet for workers. If the filter cap is replaced with the application of a sheet of silt screen material about the body portion only, the domed top portion of the silt retention device itself can be painted a fluorescent color to make it more recognizable and identifiable. 
     As indicated above, the silt retention device can be framed with the base plate, or can be formed with a rim in place of the base plate, and can be framed as a separate, generally standardized component. Different size and/or configuration base plates and/or adapter also can be formed as individual or separate components that can be designed/configured for particular sizes and/or configurations (or ranges thereof) inlets or other drainage structures. The adapters and base plates (if needed) then can be selected to match a particular application and mounted to the silt retention device body as needed in the field to extend the coverage of the silt retention device and provide further stability to the mounting of the silt retention device, enabling its use with a variety of drainage structures. 
     In an alternative method of forming the silt retention assembly, such as the silt retention assembly  10  of  FIG. 1 , according to the present disclosure, a first mold can be provided/formed for forming the body of a silt retention device comprising an end, and framework structure intermediate to the upper end and the lower end, with a series of water permeable openings therein. The body can be molded from a plastic or synthetic material, as a stand-alone piece or component. Alternatively, one or more secondary molds can be mountable to the first or base mold, for example with an attachment portion configured to accept a second mold. The second mold can be configured to form a base plate and/or an adapter for the silt retention device, wherein the base plate and/or the adapter comprise a flat portion extending outwardly along a longitudinal axis from the lower end of the silt retention device, the base plate and/or the adapter including a foldable feature downwardly extending from the flat portion. Still further, a separate, third or additional mold for forming the adapter can also be attached to the second mold to form a customized, unitary mold structure. Thereafter, the silt retention device, the base plate and/or the adapter can be molded as a single structure. 
     Although only a few exemplary embodiments have been described in detail herein, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of the embodiments of the present disclosure. Accordingly, all such modifications are intended to be included within the scope of the embodiments of the present disclosure as defined in the following claims. In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents, but also equivalent structures.