Abstract:
The environment and growth of vegetation within a soil embedded culvert system is improved by directing artificial or natural light onto the vegetation within the enclosed passage defined by the culvert system. The light is produced either by internal electrical grow light fixtures or by external sunlight reflectors. A water spray system may also be used within the passage to improve the vegetation growth.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     As development across the United States continues to increase, the miles of roadway and number of stream crossings also increase. These roadways and crossings can have a potentially devastating effect on fish and wildlife in the area. Roadways often divide animal habitat, fragmenting populations and impeding migration patterns. While some wildlife passages have been implemented, they are still often inadequate or go unused due to the lack of natural vegetation and darkness in longer underground crossings. These wildlife passages, especially those for large mammals continue to become more important as the number of vehicle-animal incidents continues to increase.  
         [0002]     The water stream crossings, which result as part of roadway development, are often inadequate because vegetation on the adjacent stream banks is shaded out and unable to grow. These shaded, barren stream banks no longer provide a habitat for aquatic life and discourage fish from moving upstream. In addition, the absence of vegetation may enhance scour or erosion problems due to the stream.  
         [0003]     Thus, a significant limitation in culvert and bridge system design for environmentally sensitive areas is the changing of the natural habitat of streams, adjacent banks, and wildlife corridors. This alteration of the natural habitat can result in the elimination of plant growth and impede the migration of fish and wildlife in the area.  
         [0004]     According to the Transportation Research Board (TRB) of the National Cooperative Highway Research Program, Project 25-27, FY 2004, “Every year, the costs of personal injuries and property damage resulting from animal/vehicle collisions are considerable. Various means have been employed to mitigate these collisions, with varying degrees of success. In recent years, highway agencies have placed a growing emphasis on protecting the environment. While many smaller species of animals do not pose a threat to vehicles through collisions, they experience significant habitat loss and fragmentation as a result of roadway alignments. Transportation corridors limit the natural movement of wildlife, affecting individual species and ecosystems.” 
       SUMMARY OF THE INVENTION  
       [0005]     The present invention involves the method of using a lighting system and sometimes a watering system within enclosed environmentally sensitive underground culverts and bridges. The systems comprise lighting systems designed to provide natural or artificial light within the bridge or culvert corridor or passage along the length of the passage and may include the distribution of water for environmental and wildlife benefits. The systems described herein may be implemented in conjunction with each other or may be used separately, depending upon environmental needs.  
         [0006]     In accordance with preferred embodiments of the invention, the above features and advantages may be provided by installing a series of electrical plant growth lighting fixtures within an underground culvert or bridge assembly along the length of the assembly and by planting vegetation within the earth or soil extending within the passage defined by the culvert or bridge assembly. The lighting fixtures are connected by electrical conductors to a suitable power source which may include rechargeable storage batteries and a solar cell system for charging the batteries. The light generated from the lighting fixtures results in producing growth of the plants or vegetation within the culvert or bridge assembly along its entire length. The invention also provides for a water distribution or spray system along the length of the culvert or bridge assembly from spray nozzles attached to the assembly at spaced intervals along the length of the passage and connecting the spray nozzles by conduits to a suitable water supply source. The invention further provides for directing natural light into the passage defined by the culvert or bridge assembly by the use of natural light reflectors located externally of the assembly.  
         [0007]     Other features and advantages of the invention will be apparent from the following description, the accompanying drawings and the appended claims. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]      FIG. 1  is a perspective view of an underground culvert or bridge assembly incorporating an internal lighting system along the length of the assembly in accordance with the invention for improving the environment and growth of vegetation within the assembly;  
         [0009]      FIG. 2  is a cross-section of the underground culvert or bridge assembly shown in  FIG. 1 , taken generally on the line  2 - 2  of  FIG. 1 ;  
         [0010]      FIG. 3  is a section of a culvert or bridge assembly similar to  FIG. 2  and showing a water distribution system along the length of the assembly, in accordance with the invention; and  
         [0011]      FIG. 4  is a perspective end view of a culvert assembly similar to  FIG. 1  and illustrating generally a reflective lighting system for improving plant growth within the culvert assembly in accordance with the invention. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0012]     Referring to  FIG. 1 , an underground culvert or bridge assembly  10  includes a series of precast reinforced concrete culvert or bridge units or sections  12  each of which includes parallel spaced side walls  14  integrally connected by an arch-shaped top wall  16  to form a three sided open bottom section or unit. Each of the culvert or bridge units  12  may be constructed as disclosed in U.S. Pat. No. 4,687,371 which issued to the assignee of the present invention. While three of the precast concrete units  12  are illustrated in  FIG. 1 , the bridge assembly  10  may include many of the sections  12  and have substantial length, for example, over 50 or 100 feet. The bridge or culvert units  12  may also be constructed with a flat top wall or integrally connected with a bottom wall to form a box-like culvert or bridge assembly. In addition, in place of having a series of precast concrete culvert units which are assembled at the construction site, the culvert or bridge assembly may be constructed as a cast-in-place bridge or culvert or be constructed of metal culvert or bridge sections or units.  
         [0013]     In accordance with the present invention, the earth or soil S surrounding the culvert or bridge assembly  10  is extended through the passage  20  defined by the assembly, and vegetation V in the form of grass, ground cover or plants is planted along the length of the assembly and within the passage  20 . When used as an underground culvert assembly, a stream of water W may also flow through the bottom of the passage  20  between adjacent soil banks B which are planted with the vegetation V. In order to enhance the growth of the vegetation V, a lighting system  25  is installed within the culvert or bridge assembly  10  along the length of the passage  20 . As illustrated in  FIGS. 1 and 2 , the lighting system  25  may include a series of grow light fixtures  30  located at longitudinally spaced intervals along the length of the assembly  10  and passage  20  above the banks B of vegetation V.  
         [0014]     The electrical lighting fixtures  30  are connected by electrical conductors  32  and  34  to an electrical power source or supply  35  which may include a rechargeable storage battery  37  recharged by a bank of solar cells  39  or an external electrical power source  42  or a combination. The lighting fixtures  30  are provided with electrical grow light elements which produce growth of the vegetation V along the entire length of the passage  20  formed by the culvert or bridge assembly  10 .  
         [0015]     Referring to  FIG. 3 , an elongated culvert or bridge assembly, such as the assembly  10 , may also be provided with a water distribution or spray system  45  along the length of the passage  20  as formed by the assembly  10  and above the banks B of vegetation V. Preferably, the watering system  45  includes a series of water spray or misting nozzles  46  which are installed along the length of the assembly  10  either within or on the top wall  16  of each culvert or bridge unit  12 . The spray nozzles  46  are connected by a water supply line or conduit  48  to a timer and controller  50  connected to a water supply source or line  52 . The water sprays or mists from the nozzles  46  are preferably supplied at timed intervals and also provide for enhancing or promoting growth of the vegetation V within the banks B of soil extending through the culvert or bridge assembly below the top wall.  
         [0016]     As illustrated in  FIG. 4 , the growth of the vegetation V within the banks B along the length of the culvert or bridge assembly  10  may be enhanced or promoted by a natural light reflective system  60  including a plurality of external light reflecting elements  62  located at opposite ends of the culvert assembly and supported by corresponding brackets  63 . The elements  62  are positioned to reflect sunlight into the passage  20  along the length of the soil banks B. The reflective elements may be mounted on opposite end walls  64  of the culvert assembly or on wing walls  66  connected to opposite ends of the culvert assembly  10 . Since the natural light reflecting elements  62  do not require any electrical power source, the light reflective system  60  eliminates the cost of an electrical power supply.  
         [0017]     As mentioned above, the above described lighting and watering systems may be used together or separately, as conditions require. The artificial or natural light, as well as water distribution, within the passage  20  of the bridge or culvert assembly promote native plant or vegetation growth within the soil forming the adjacent stream banks B. By promoting the plant growth in the covered area under the bridge or culvert assembly, the systems reduce or prevent stream scouring or erosion as well as adding habitat area for fish and other animals. The plant growth also encourages fish and wildlife migration through the passage  20 . This results in an improved wildlife corridor and maintains the ecology of the area around the culvert.  
         [0018]     While the methods and systems herein described constitute preferred embodiments of the invention, it is to be understood that the invention is not limited to the precise methods and systems described, and that changes may be made therein without departing from the scope and spirit of the invention as defined in the appended claims.