§ 181-8. Temporary limitation on sewer extensions., Chapter 181. Water and Sewer Main Extensions, Code of Ordinances, Lebanon

Purpose and findings.

(1)

A sewer line capacity study performed by Wright-Pierce Engineering in the course of the Planning Board's preliminary review of the proposed Carter Country Club - Houses on the Hill development, and the results of which are reflected in a report with a cover letter from Ryan T. Wingard, P.E., to City Engineer Christina Hall, P.E., dated July 17, 2017, and in a memorandum from Wright-Pierce to the City Engineer and Jay Cairelli, Assistant Director of Public Works dated July 24, 2017, has determined that portions of the sewer interceptor connecting Downtown Lebanon to the wastewater treatment facility (all areas east of the Terri Dudley Bridge, as shown on Exhibit A) - when flows from already approved but unconstructed development are factored in - are nearing their capacity (considered conservatively by the City as 80% of calculated full flow). Specifically, the Wright-Pierce study found that the existing residual capacity of the sewer interceptor, in the absence of any pipe replacements, was 110,000 gallons per day.

(2)

The City finds that the conclusions of the Wright-Pierce study evidence a clear and present emergency which must be addressed on a temporary basis pending remedial actions to increase the overall capacity of the line, in order to prevent the approval of sewer extensions, or combinations thereof, which, if implemented, could bring about a failure or overflow of the sewer interceptor, and cause serious health and environmental damage as well as violations of clean water and pollution laws.

(3)

When calculating residential sewage flows, the City has historically utilized a figure of 150 gallons per day per bedroom for a single-family dwelling (600 gallons per day for a four-bedroom house). To allot for wet weather conditions within the sewer system, this figure is peaked by a factor of six (or 3,600 gallons per day for a four-bedroom house).

(4)

In presentations made to the Council, representatives of both Wright-Pierce and Weston & Sampson have recommended that - in addressing the question of interceptor capacity - it would be reasonable for the City to reduce its sewage flow estimates associated with residential units to a level which, while still conservative, is closer to the figures used by New Hampshire Department of Environmental Services.

(a)

The City accordingly finds that, based on the information presented, utilizing the Metcalf and Eddy/AECOM Wastewater Engineering Treatment and Resource Recovery, Fifth Edition, Table 3-2, (assuming one person per bedroom) is the method to be used as follows:

1 bedroom flowrate = 103 gpd/capita x 1 person = 103 gpd = 105 gpd rounded

2 bedroom flowrate = 77 gpd/capita x 2 people = 154 gpd = 160 gpd rounded

3 bedroom flowrate = 68 gpd/capita x 3 people = 204 gpd = 210 gpd rounded

4 bedroom flowrate = 63 gpd/capita x 4 people = 252 gpd = 280 gpd rounded

(b)

In applying this calculation method to those developments previously approved, but not yet constructed (specifically ICV Phase II and 4 South Park Street), the recalculated residual capacity of the interceptor is 153,559 gallons per day.

(5)

Sewer extensions/connections granted.

(a)

The following sewer extensions/connections have been granted since the completion of Wright-Pierce's study of the interceptor capacity:

Thai Orchid Restaurant (Hanover Street) = 48 seats, 48 seats x 40 gal/seat X 6 = 11,520 gpd peaked

Lucky's coffee shop and bar = 980 gpd x 6 = 5880 gpd peaked (980 gpd based on 3 employees at 35 gpd and 54 seats at 20 gpd — 1 sewer unit for preexisting use.)

1 single-family home (2 bedroom) = 960 gpd peaked.

(b)

Applying the total allocation for those flows approved since the completion of Wright-Pierce's study (18,362 gallons per day) to the recalculated capacity when applying the Metcalf and Eddy method (153,559 gallons per day) yields a total new residual capacity of 135,997 gallons per day that may be allocated to future development.