SECTION X - CONSTRUCTION STANDARDS AND SPECIFICATIONS
A. Street Design and Construction Standards
1. The arrangement of streets in the subdivision shall provide for the continuation of the principal streets in adjoining subdivisions or for their proper projection when adjoining property is not subdivided, and shall be of a width at least as great as that of the existing connecting streets. Any newly created street must connect with an accepted street in the Town of North Hampton.
2. No street or highway right of way shall be less than 50 feet in width and may be required to be more if a greater street width is warranted in the opinion of the Board. The apportioning of street widths among roadways, sidewalks, and possible grass strips shall be subject to the approval of the Board.
3. No deadend or cul-de-sac streets shall be allowed; but if a street has a turn around at its end and said turn around contains at least a lot of legal size, the turn around will not be considered a cul-de-sac. No street that begins in North Hampton shall extend into another town without connecting with an existing street in that town.
4. The widths of blocks shall not be less than four hundred (400) feet.
5. Grades of all streets shall conform in general to the terrain and shall as far as practicable, not exceed 5% for major streets and 8% for minor streets. No street shall have a grade of less than 1/2 of 1%. All streets shall have a crown at the center with slopes of not less than 1/4" per foot from crown to sideline of surfaced roadway. The maximum grade within 100 feet of a street intersection shall be 3%.
6. Intersecting property lines at street intersections shall be joined by such curve of at least 20 foot radius. The minimum angle of two street intersections shall be 75 degrees.
7. The minimum centerline radius of curves and the maximum degree of curvature shall depend on the design speed and the slope of the road, as determined by Table V-6 of A Policy on Geometric Design of Highways and Streets 1984 by the American Association of State Highway and Transporta-tion Officials.
8. Shrubbery, trees or other obstructions of street corners shall be subject to such regulations as the Board may require.
9. Streets which join or are in alignment with streets of abutting or neighboring properties shall bear the same name. Names of new streets shall be named by the Board of Selectmen.
10. Where access to a subdivision depends on use of an existing public street(s) which does not meet the standards established in these regulations, the applicant shall improve such public street(s) or contribute to the improvement of such public street(s), in a sum equal to the proportionate use his subdivision will impose on said public street(s), assuming that all lands served by said public street(s) will eventually be similarly subdivided.
11. The Board of Selectmen may agree to plow and to apply winter surface treatment to a street once the performance security has been released, in total or in part. However, the Town shall not be responsible for any damage resulting from such plowing or treatment. All repairs to streets prior to acceptance of the deed for the street by the Board of Selectmen shall be accomplished by the person or persons or other entity offering the street for acceptance by the Town.
B. Roadway Specifications
1. All streets shown on the plan shall be graded to a depth of not less than 12 inches with gravel, covered with not less than 6 inches of selected gravel and shall be surfaced with an application of not less than three inches of base and one inch of hot top all in accordance with the NH Department of Transportation specifications. Sidewalks, if required, shall be separated from the shoulders by curbing or at least three (3) feet of grass planting and shall be four (4) feet wide. A finished road shall consist of a minimum of twenty-four (24) feet paved (travel) surface, four (4) feet of graveled shoulders on each side of pavement, and a gutter area capable of conducting water from one catch basin to another such that the minimum length between
catch basins is 400 feet.
2. Within the "right-of-way" to be paved, all stumps, rocks and ledge shall be removed, and ledge (or ledge fill) shall be kept at least two (2) feet below the finished surface profile.
3. All road bounds, grades, and contours, as well as all drainage pipes, culverts, and facilities shall be installed by grades established by a qualified engineer and shall be checked and certified by him, and any necessary corrections made under his supervision before the same may be submitted to the Town for acceptance.
4. The sub-base or base course under each street pavement shall be constructed as follows:
a. The base course under each street shall be composed of (1) bank run gravel with no stones larger than 6 inches, compacted to a minimum thickness of 12 inches (2) Select gravel, compacted to a thickness of six (6) inches, in accordance with The State of New Hampshire Department of Transportation Specifications for Crushed Gravel.
b. Base course shall not be constructed during freezing weather or on a wet or frozen sub-grade.
c. Grading and rolling shall be required to provide a smooth, even, and uniformly compacted base which is compacted to a minimum dry density of 95 percent. Compaction shall be tested at the expense of the contractor by an approved laboratory designated by the Town.
d. A minimum slope from crown edge of pavement of the finished base course shall be 1/4 inch per foot.
e. All unsuitable material shall be excavated and brought up to grade with satisfactory material.
f. At all times during construction, the sub-grade and all ditches shall be constructed and maintained so that the roadway will be effectively drained.
g. In areas where unsuitable soils are encountered in the sub-base, the depth of the bank run gravel shall be more than twelve (12) inches as specified.
h. Materials used for gravel sub-base and crushed gravel base shall meet or exceed standards described in Standard Specifications for Road and Bridge Construction, State of New Hampshire, Department of Transportation, 1990 as amended. Gradation tests performed by an independent laboratory, approved by the state to perform such tests, will be required for each type of material and shall be paid for by the subdivider.
C. Drainage Specifications
1. All storm drainage pipes shall be not less than twelve (12) inches, and designed for a 100-year storm by a registered professional engineer. Catch basins shall be pre-cast or solid block four (4) feet in diameter and the outlet pipe at least 3 feet above bottom of barrel section, all in accordance with the latest edition of the New Hampshire Department of Transportation Specifications for Road and Bridge Construction.
2. The stormwater system shall include an adequate number and sizes of catch basins and/or drop inlets such that the maximum length for a ditch to a catch basin is 400 feet, and shall be designed by a registered engineer for a 100-year storm.
3. No stormwater pipe, catch basin, drainage inlet, or cellar floor drain, draining surface or subsurface groundwater shall be connected to the sanitary sewer system if and when one exists. All storm water pipes shall be inspected by the Town Engineer or Road Agent before being covered. A 24 hour notice will be required before inspections.
4. The subdivider shall show evidence that his stormwater drainage system will not cause flooding or excessive siltation of waters upon or adjacent to the subdivision. Easements for stormwater pipes or drainage ditches will be required when they will be crossing private land. These easements shall be deeded to, the Town of North Hampton.
D. Water Lines
Whereas the Town is experiencing water contamination in individual wells, the following regulations are required:
1. When at the discretion of the Board it is feasible, a subdivider shall, at his expense, install a public water system, including necessary main extensions, in all streets shown on the plan.
2. In subdivisions where the Board does not require a public water system, the subdivider at his expense shall install mains, laterals to all lots, and connections for fire hydrants (all meeting water company standards) for future use when public water connection is available.
E. Inspections
1. The subdivider shall notify the Town Engineer and the Highway Agent as to the readiness for inspection of any such street at each stage of its construction. Approval or disapproval of any segment by the Town Engineer and the Highway Agent shall be in writing, with a copy to the Selectmen, and shall constitute only a recommendation relative to whether or not the Town shall accept the street concerned.
2. The following inspection schedule shall be abided by during construction of streets. The inspections shall be performed and documented for each item by a registered engineer retained by the Town at the expense of the developer.
a. Review of design engineer's layout and wetlands marking.
b. Inspection of clearing and grubbing and erosion control measures.
c. Inspection of fill placement. In-place compaction testing of fill is required every 3,000 square feet or as directed by the Town Engineer.
d. Inspection of drainage piping and buried utilities. Full time inspection is required, including the trench backfilling.
e. Inspection of sub-grade and slope work.
f. Inspection of gravel grade. Compaction testing of the gravel coarse is required every 200 linear feet of roadway.
g. Inspection of crushed gravel grade. Compaction testing of the crushed gravel coarse is required every 200 linear feet of roadway.
h. Inspection of final ditch work, slope work, landscaping and erosion control measures.
i. Inspection of headwall construction.
j. Inspection of binder coarse paving. Full-time inspection will be performed during the paving. After the binder coarse pavement and all work required prior to that point has been completed, the Developer can request, in writing, a reduction of the roadway bond to the Selectmen. The exact amount of the bond reduction is to be determined by the Selectmen.
k. Inspection of the wearing coarse pavement. Full-time inspection is required.
l. Remaining work inspection by developer and Town Engineer.
m. Final walk through inspection by the Town Engineer, Board of Selectmen, and Highway Agent.
n. Follow-up inspection.
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