HomeMy WebLinkAbout20191587 Ver 1_Future Situation_20191115
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system was last upgraded around 2007 (Exhibit B, Appendix B). Based on current visitor records
and written notifications from environmental agencies, the sewer system flow from staff and visitors
has exceeded the permitted flow and will need immediate attention.
There are no accurate records of how much wastewater is generated from this facility. The peak
water usage during the summer months is approximately around 240,000 gallons per month. The
low flow water usage is approximately 65,000 gallons a month. For the purpose of this report it will
be assumed that the average water usage is around 150,000 gallons per month.
Based on recent water sales records, monthly portable toilet usage, and pump and haul
operations, it is estimated that their average flow during the summer months maybe close to 10,000
GPD, and a maximum daily flow of up to 15,000 GPD.
SECTION 3. FUTURE SITUATION
Population Projections and Characteristics:
Population Projections:
Population projections attempt to predict future growth and where it will occur for planning
purposes. It is difficult to predict major factors such as natural catastrophes, changes in ways of
life, medical innovations, large developments, industrial expansions, fuel shortages, or other
unpredictable events, but in order to provide a basis of planning, a projection to the future
population is essential. Anticipated future populations are most confidently determined by
intensive studies of past and present trends and then correlating this data with knowledge of the
areas being analyzed. Residential population projections will be made by considering the area
currently served by the Town, along with County projections during the next 20 years.
Population information utilized by this report was obtained from the U.S. Census Bureau,
interviews with County/Town personnel, the recently adopted 2035 Comprehensive Land Use &
Master Plan, and public information available on the internet and other resources found in
Appendix D.
According to the above sources, the population in Andrews has remained relatively the
same in the last several years, at approximately 1,800. Similarly, the Cherokee County population
has slightly increased over the last few years with county population being at 28,000.
Refer to Table 3.1 in this report for Population Data and historical trends in Cherokee
County and the Town of Andrews.
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Table 3.1. Town and County Population Data
Sewer Line Extension to Snowbird Wilderness Outfitters
Town of Andrews, Cherokee County, North Carolina
1990 2000 2010
Cherokee County 20,170 24,298 27,444
Town of Andrews 2,551 1,602 1,781
Source: U.S. Department of Commerce, Bureau of the Census.
A significant decline in growth rate has been observed over the 1990 to 2000 period due
to the de-annexation of the Valley-town Township, followed by a small recovery over the last 15
years. Similarly, Cherokee County has seen a slight growth in population growth of almost 35%
over the last 25 years.
According to the historical data from the 2035 Land Use Comprehensive Masterplan, the
projected growth rate for the Town of Andrews using the Geometric Projection method for the
next 20 years is shown on Table 3.2.
Table 3.2. Town of Andrews Population Projections
Sewer Line Extension to Snowbird Wilderness Outfitters
Town of Andrews, Cherokee County, North Carolina
Projected Year 2010 2020 2030 2040
Population 1,781 1,882 1,989 2,090
Based on the referenced future projections, a slight growth rate of approximately 5 %
every 10 years is anticipated in this area.
Populations characteristics:
Populations characteristics in the planning area based on the 2010 US Census and the
2035 Comprehensive masterplan are described below:
There are approximately 780 households within the Andrews town limits with an average
household size of 2.19 and an average family size of 2.9 persons. Approximately 88.8% of the
citizens are of Caucasian (white) origin, 7.5% of Hispanic or Latino origin, 1.3% of African
American origin, 1.1 % of American Indian origin, 1% of Asian origin, and 3.8% of other origins.
The median age of population in Andrews is 33.8 years.
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The homeownership in Andrews is roughly at 71% while the majority owner-occupied
home values fall below $100,000.
Roughly 25 percent of the homes are older than 50 years old, approximately 65 percent
are between 20 to 50 years old and only 10 percent are 10 years old or newer.
The median household income and per capita income are $23,594 and $12,167
respectively. For comparison purposes, the NC State averages are twice as much, while the
Cherokee County numbers are approximately 50 percent higher.
Similarly, the percent of individuals under the poverty level are 29.8% while the percent of
families under the poverty level is roughly at 23.2 %. For comparison purposes, the NC State
averages are half the reported numbers, while the Cherokee County is 10 percent lower across
the board.
The majority of employment is in the service sector (33.6%), followed by management,
science, and arts occupations (25.3%). The remaining percentage is spread between
entertainment, recreation, accommodation and food services. The rate of unemployment for
Cherokee county (not available for the Town) is at its highest in the last 10 years, at 10 percent.
Refer to Appendix D for additional information on the Town, and Regional demographics.
Flow Projections:
The future growth potential and capacity need for the project planning area is presented
in this section. Projections are based on a 20-year design period.
The growth potential of the planning and service areas is the most important factor in
projecting the future infrastructure requirements. The two (2) key areas to be investigated include:
the institutional sector (Snowbird Camp), and the residential sector. The anticipated growth as
described elsewhere in this report is numerically summarized below:
1) Institutional Development:
According to the economic and community development projections, some institutional
growth is anticipated during the 20-year projected planning period for this area. For planning
purposes, the following design criteria and assumptions will be utilized:
Current Average Snowbird Staff = 120 people/day
Current Average Summer Visitors = 600 visitors/day (Exhibit A)
Future Average Snowbird Staff = 180 people/day (assumed)
Future Snowbird Summer Visitors = 900 visitors/day (Projection based on Exhibit D,
Appendix F)
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Assume 600 students in summer day school
Assume 300 student visitors from Retreats and Conferences
Therefore:
Future Staff Flow = 180 staff people x 25 gpd/employee (Item A, Exhibit A, Appendix I)
=4,500 GPD
Future School Flow = 600 summer day school visitors /day x 15 gpd/person (Item B,
Exhibit A, Appendix I) = 9,000 GPD
Future Conference Flow = 300 conference visitors/day x 5 gpd/visitor
(Item C, Exhibit A, Appendix I) = 1,500 GPD
Total Future Institutional Flow Projection = 4,500+ 9,000+ 1,500
= 15,000 GPD
Therefore, for planning purposes, we will use 17,500 GPD.
2) Residential Development:
The residential projections over the 20-year planning period are typically estimated
by investigating U.S. Census information of the Town, County, and State, by considering
upcoming area projects/developments that involve new house construction, and by estimating the
number of septic tank conversions to public sewer. These areas have been investigated as such,
and the projected outcome is listed below:
i) Current customers to be served:
The assumption that no residential customers will be connected to the proposed
sanitary sewer line at startup, will be assumed for planning purposes. Up to 30
potential customers may be connected in the immediate future (Refer to Exhibit A-
1 in Appendix A for more information) from septic tank conversions.
ii) U.S. Census Contribution:
Based on the U.S. Census Bureau, the estimated annual population growth
for the Town of Andrews is estimated to slightly increase over the next 20 years as
previously discussed in the demographic information section in this report.
Therefore, the additional flow projection due to population growth over the
next 20 years for this area is:
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Potential customers to be served = 30 customers x 5% growth rate/10-year
x 2 ten year periods = 3 new customers in 20 years.
ii) Similarly, according to the local planning office, and other Town Officials,
there are no known plans for new residential development during the next several
years:
However, for planning purposes, and in order to account for future
unforeseen residential growth, and further septic tank conversions, we will
consider an additional 50 new units as the projected growth during the next
20 years.
Therefore;
1) Additional Residential Growth from known and unforeseen sources:
50 Home Units
2) Additional Residential Growth from Population Projections:
33 Home Units
Total New Customers to be gained over the next 20 years = 50 + 33
= 83 Customers
For planning purposes, we will use 90 future customers.
Therefore, Additional Future Residential Flow is determined as follows:
Assuming 3-Bedroom House Generates 360 GPD/House (Item E, Exhibit A,
Appendix I)
Assuming 2-Bedroom House Generate: 240 GPD/House (Item D, Exhibit A,
Appendix I)
And Assuming 50 Houses are 3-Bedroom, while the Remaining 40 Houses
are 2-Bedroom;
Projected Flow = 50 Units x 360 GPD = 18,000 GPD
40 Units x 240 GPD = 9,600 GPD
Therefore, Total Future Residential Flow Projection = 27,600 GPD
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In order to determine the future average design capacity of the proposed infrastructure, the
institutional and residential flows were added together;
Therefore, the average design daily flow = 17,500 GPD + 27,600 GPD= 45,100 GPD (42 gpm-
18hr Q)
Similarly, and according to 15A NCAC guidelines, and using a peak/average flow ratio of 4, the
peak daily flow in the proposed sewer line will be approximately
= 4 x 45,100 GPD = 180,400 GPD (168 gpm- 18hr Q).
Downstream Sewer Analysis for Future Situation:
According to preliminary information provided by the Town, the existing 8” gravity line
(vitrified clay material) along Aquone Road has enough reserve capacity for this line extension.
Based on the previous flow analysis, the average projected flow will be 42 gpm and the daily peak
instantaneous flow will be 168 gpm (18-hour flow estimates). Similarly, the WWTP has enough
reserve capacity to accept the additional flow also. The percent of new flow to the plant capacity
is 45,100 gpd/ 1,500,000 gpd is approximately 3%. The current plant flow is at 0.4 MGD. The
projected plant flow from this project will be 0.45 MGD. The reserve capacity to the WWTP will be
1.5 MGD – 0.45 MGD = 1.05 MGD.
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Table 3.3. Future Flow
Sewer Line Extension to Snowbird Wilderness Outfitters
Town of Andrews, Cherokee County, North Carolina
Supporting Information Appendix Reference:
Project Contains: Pump Stations/Force Mains Gravity
Sewers
Complete this table in accordance with Section 6.4 of the guidance.
Pump Stations/Force Mains
Name
Firm Pumping
Capacity
(gpm)
Current Peak
Flow
(gpm)
Future Peak
Flow
(gpm)
% Change in
Flow
% Capacity
Utilized
Gravity Sewers
Name
Capacity
(gpd)
Current Peak
Flow
(gpd)
Future Peak
Flow
(gpd)
% Change in
Flow
% Capacity
Utilized
Aquone Road 470,880 100,000 280,400 180% 60
Future flows established based on future projections and 15A NCAC guidelines.
Existing line capacity determined based on minimum pipe slope for 8” line.
Current peak flow was assumed.
SECTION 4 – NEED AND PURPOSE
Purpose:
The Snowbird Wilderness Outfitters is a major employer and a large visitor attraction sit e (camp)
near the Town of Andrews. The camp is located on the outskirts of the corporate limits. The
camp site has surpassed its projected growth and is currently experiencing problems collecting,
treating, and disposing sanitary wastewater from its facilities. Portable bathrooms along with
periodic pump and haul operations are employed to keep up with the growing number of
visitors. In addition, the camp has plans to expand their operations and construct new buildings
at the current site. The County Health Department will not permit such construction unless the
Snowbird’s on-site sewer treatment and disposal system is upgraded, or other such sewer
services are provided. The Town of Andrews has previously expressed interest in providing
sanitary sewer services to this Camp, and the residential areas along the way, as part of the
previously prepared 2035 comprehensive masterplan. This report will examine ways to