STORM DRAINAGE AND FLOOD CONTROL PLAN T ! COUNTY new jersey The preparation of this report was financialfy aided through a Federal grout from me Urban Renewal Adminiitration of the Department of Housing and Urban Development 'mder the Urban Planning Assistance Program authorized by section 701 of the Housing Act of 1954, as amended. The remainder has been financed by local funds and by an appropriation of the state of New Jersey as port of the Cooperative Governmental Planning Program. Prepared by : ELSON T. KILLAM ASSOCIATES, INC. APRIL UNION COUNTY 1971 PLANNING BOARD ELSON T. KILLAM ASSOCIATES, INC. VIII. CHRONICALLY FLOODED AREAS Exhibit XV shows the locations of reported areas of frequent flood­ ing within Union County. Two basic distinctions have been made tidal flooding and flooding from storm water runoff. The areas of tidal flooding shown on Exhibit XV will generally occur during a fifty-year frequency tide with tidal elevation of +10' and with no storm water runoff. The total area inundated under such conditions has been estimated to be approximately 4,800 acres or 7.3 percent of the total land area of the County! The method of reducing this extensive area of flooding is discussed in Chapter IX of this report. Other areas of frequent flooding shown on Exhibit XV occur from storm water runoff during periods of heavy rainfall. Questionnaires were sent to each municipality in the County requesting data on the location and description of areas of frequent flooding. It was re­ quested that areas of flooding be predicated upon occurring on the average of at least once every five years, cause extensive property damage, endanger human lives, or halt travel on arterial streets. A form was prepared and submitted to each municipality to provide answers to the following questions:' 1. What locations are frequently flooded? 2. What is the frequency of flooding? 3. What is the depth of flooding in streets? 4. What is the cause of flooding? 5. Are improvements planned and, if so, when? 6. Is the flooding beyond the control of your municipality? - 46 - ELSON T. KILLAM AS SOCIATES, INC. The locations reported have been plotted on Exhibit XV and have been divided into three classifications. The first, stream flooding denotes areas where extensive flooding occurs as a result of a major water course overflowing its bank. The causes of flooding of this variety are generally insufficient stream channel capacity, insuffi­ cient bridge capacity, encroachment into the flood plain or the in­ adequacy of a major conduit. The second classification, severe local flooding, has been used to describe areas where a limited area is flooded but flooding is frequent, property damage is high, human lives are endangered, or traffic is halted on arterial streets. Local flooding has been placed in this classification, particularly where the flooding occurs on State or County roads or the flooding in one municipality may result from inadequate facilities in another municipality. The causes of this type of flooding are generally a stream channel restriction, an inadequate bridge or culvert, or a grossly inadequate local collection system. The third classification, minor local flooding, has been used to show those areas where flooding was reported to occur but does not create the condition specified under severe local flooding and is generally within the control of a single municipality. In this report, emphasis has been placed upon tidal flooding, stream flooding and severe local flooding. IX. TIDAL FLOODING PROGRAM Tidal flooding in the eastern area of Union County is a relatively frequent occurrence. Exhibit XVI, Flood Tide Frequencies, shows that the yearly high tide is at elevation +5.8'. The fifty-year frequency tide reaches elevation +10.0'. (All elevations are in feet above mean sea level as measured at Sandy Hook, New Jersey.) - 47 - i s™%, r™ KILL.N. h- LiJiu u. ELEVATIONS IN FEET ABOVE MEAN SEA LEVEL AT O SANDY HOOK, NEW JERSEY SOURCE; u.s. ARMY CORPS OF ENGINEERS ELSON T. KJI.LAM ASSOCIATES, INC ffyJr&mlic and Samt&ry Engineers 48 ESSEX STREET, MtLLBURN. NEW JERSEY O7O.4! 10 20 30 40 50 60 80 iOC 1 X\/ HI J 1B!I $*% 1 T"T" ELSON T. KILLAM ASSOCIATES, INC. The discussion of the tidal area adjacent to the Arthur Kill will be made in two sections. The first section will deal with the area east of the New Jersey Turnpike and the second, the area west of the Turnpike. An area of approximately 2,800 acres east of the New Jersey Turn­ pike is below elevation 10.0'. With the exception of the Elizabethport area, the land use is generally heavy industrial, petrochemical, or vacant tidal marsh. In some locations, buildings and bulkheads have been constructed directly adjacent to the Arthur Kill. In other loca­ tions, tidal marshes border the Arthur Kill. The industrial residents of this area have constructed their facilities with full awareness of the inevitability of periodic flooding during periods of extremely high tides. Protection of the entire area land east of the Turnpike against periodic tidal flooding, even if desired, would not be economically feasible. The soil conditions adjacent to the Arthur Kill and the extremely long dike that would be required to prevent flooding are the controlling factors. However, local areas east of the Turnpike may be protected by either placing fill to the desired elevation or by the construction of limited dikes and local pumping facilities. There are approximately 2,000 acres west of the New Jersey Turn­ pike which are below elevation +10.0' which are susceptible to periodic flooding from high tides. However, the construction of the Turnpike to elevation +12 has isolated this area from the Arthur Kill, with the exception of only nine locations. These are the bridges and - 48 - ELSON T. KILLAM ASSOCIATES, INC. culverts for the major streams listed below: 1. Rahway River, Linden 2. Marshes Creek, Linden 3. Piles Creek, Linden 4. Morses Creek, Linden 5. A Culvert at Standard Oil, Linden 6. A Culvert Near Alien Street, Linden 7. Elizabeth River, Elizabeth 8. Great Ditch, Elizabeth 9. Bound Creek, Elizabeth All tidal flooding which inundates areas west of the Turnpike enters through these nine culvert locations. Where the area east of the Turnpike is primarily susceptible directly to tidal flooding, the low areas immediately west of the Turnpike are generally susceptible to both tidal flooding and storm runoff. For this reason, simply closing off these nine openings during periods of flood tide is not a solution. There are two means of solving this problem of extensive flooding west of the Turnpike during high tides. The first is to provide tide gates and a pump station at the Turnpike crossings to prevent tide water enty and to discharge the flow of the stream into the Arthur Kill during high tides. This type of installation was proposed for the area tributary to Bound Creek, known as Newark Meadows project, to protect the low-lying areas - 49 - ELSON T. KILLAM ASSOCIATES, INC. in the City of Newark and Frelinghuysen areas from frequent flooding during high tides and heavy rainfalls. This is a proposed City of Newark Project which would also benefit tributary areas of the City of Elizabeth. The second approach to limiting the tidal flooding of low lying areas is to construct dikes and levees along the river banks and to provide pump stations to eject the local runoff into the River. This approach has been recommended by the United States Army Corps of Engineers for the Elizabeth River and has been undertaken, in part, in the City of Rahway. For more detailed discussion, the area west of the New Jersey Turn­ pike has been divided into the four natural drainage basins: 1. Newark Airport, Bound Creek 2. Elizabeth River 3. Morses Creek 4. Rahway River 1. Basin 1, Newark Airport is defined as that area north of Livingston Street in Elizabethport. A substantial area of the City of Newark, Newark Airport and a large area of Elizabeth are drained by a peripheral ditch which skirts the west, south and southeastern boundaries of Newark Airport. This main interceptor ditch has recently been constructed by the Port Authority and provides a very satisfactory open channel outlet for storm water runoff during periods of low tides. However, during high tides, no outlet is provided for storm water runoff as the existing tide gates at the Turnpike culvert are then closed by tidal action. - 50 - ELSON T. KILLAM ASSOCIATES, INC. As a result, the storm water runoff in the peripheral ditch backs up, creating surcharge, and flooding in low-lying areas, and extensive damage and interruption to traffic results. To relieve this condition, the construction of a storm water pumping station was proposed in 1961. The Port Authority offered to contribute toward the cost of construction which would be undertaken by the City of Newark, the pri­ mary beneficiary of the proposed improvement. The report recommended that the area of Elizabeth, generally north of North Avenue and west of Division Street, also be serviced by the proposed pumping station. Since the report was prepared, the peripheral ditch has been constructed immediately north of North Avenue. The area immediately south of North Avenue, which is tributary to Great Ditch, is also susceptible to flood­ ing and is isolated from the Arthur Kill with the exception of a single culvert under the Turnpike. The tributary area to the Great Ditch at the Turnpike culvert is approximately one square mile. It has been planned to divert the western third of this drainage area, above Division Street, into the peripheral ditch. The southern portion will remain tributary to the Arthur Kill through the Great Ditch.