HomeMy WebLinkAboutFINAL - Silver Spur Estates W&WW Study
SILVER SPUR ESTATES
WATER AND WASTEWATER SYSTEM
ADEQUACY STUDY
November 2022
SILVER SPUR ESTATES
WATER AND WASTEWATER SYSTEM
ADEQUACY STUDY
November 2022
Prepared by:
SUNRISE ENGINEERING, INC.
47 East 4th Avenue
PO Box 609
Afton, WY 83110
Tel: (307) 885-8500
Fax: (307) 885-8501
Silver Spur Estates i
TABLE OF CONTENTS
1.0 INTRODUCTION ...................................................................................................................................................................... 1
1.1 General Information .......................................................................................................................................................... 1
1.2 Study Process ...................................................................................................................................................................... 1
2.0 SITE INFORMATION .............................................................................................................................................................. 2
2.1 Site Location and Topography ..................................................................................................................................... 2
2.2 Hydrogeologic Setting .................................................................................................................................................... 2
2.3 Soil Types ............................................................................................................................................................................. 3
2.4 Aquifer Characteristics .................................................................................................................................................... 4
2.4.1 Depth to Groundwater, Aquifer Material and Flow Type............................................................................... 4
2.4.2 Aquifer Thickness, Confinement & Surface Interaction .................................................................................. 4
2.4.3 Transmissivity/Hydraulic Conductivity/Gradient/Porosity.............................................................................. 5
2.5 Existing Water Rights ....................................................................................................................................................... 7
2.5.1 Surface Water ................................................................................................................................................................ 7
2.5.2 Groundwater .................................................................................................................................................................. 7
3.0 ON-SITE WASTEWATER SYSTEM ADEQUACY ............................................................................................................. 8
3.1 Percolation Rates............................................................................................................................................................... 8
3.2 Leach Field Size.................................................................................................................................................................. 8
3.3 Separation Distances ....................................................................................................................................................... 9
3.4 Shallow Impermeable Layer .......................................................................................................................................... 9
3.5 Slope of Ground Surface ................................................................................................................................................ 9
3.6 Depth to Ground Water.................................................................................................................................................. 9
3.7 Aquifer Impacts .................................................................................................................................................................. 9
3.7.1 WDEQ Appendix A Calculations ........................................................................................................................... 10
3.7.2 WDEQ Appendix B Calculations ............................................................................................................................ 11
3.7.3 WDEQ Appendix C Calculations ........................................................................................................................... 13
3.8 Wastewater Conclusions & Recommendations .................................................................................................... 14
4.0 ON-SITE WATER SYSTEM ADEQUACY ......................................................................................................................... 15
4.1 Design Considerations .................................................................................................................................................. 15
4.2 Water Quality ................................................................................................................................................................... 15
4.3 Water System Conclusions & recommendations ................................................................................................. 15
5.0 REFERENCES .......................................................................................................................................................................... 16
FIGURES
APPENDIX A – WELL PERMIT DATA WITHIN ONE MILE AND SELECT WELL STATEMENTS OF COMPLETION
APPENDIX B – SOIL MAP, SOIL MAP UNIT DESCRIPTION REPORT, AND PERCOLATION TEST DATA
APPENDIX C – WATER QUALITY DATA
Silver Spur Estates | 1.0 INTRODUCTION 1
1.0 INTRODUCTION
1.1 GENERAL INFORMATION
The purpose of this study is to evaluate the impact, safety, and adequacy of the proposed wastewater treatment
systems and water systems for the Silver Spur Estates subdivision. The proposed subdivision is located
approximately 1.5 miles north of Bedford in Lincoln County, Wyoming. The project area is in the foothills just
west of County Road 121 within Section 20, Township 34 North, Range 118 West, 6th P.M. Lincoln County,
Wyoming.
The proposed subdivision consists of 7 parcels totaling approximately 35.22 acres, with a gross density of 5.03
acres each. Actual lot sizes will vary from about 2.00-acres to 23.00-acres. The lots will be utilized for single-
family residential use. A vicinity map of the project area is shown as Figure 1, and a draft Preliminary Plat is
shown as Figure 2. Figures can be found at the end of the report.
Wyoming State Statute 35-11-302 (a) (xi) allows the administrator to consult with the County Commissioners
and the State Engineer’s Office for developing standards. These standards are administered through the
Wyoming Department of Environmental Quality, specifically Chapter 23: Minimum Standards for Subdivision
Applications. These regulations are used to determine if the water and wastewater facilities for the proposed
subdivision will be safe and adequate.
The Silver Spur Estates will use individual on-site wastewater treatment systems and individual on-site wells for
each lot.
1.2 STUDY PROCESS
This study follows the requirements set forth in Sections 7 and 8 of the Wyoming DEQ Water Quality Rules and
Regulations Chapter 23 (July 2012). This study will determine whether the proposed wastewater systems will
be safe for the surrounding environment and will be adequate for treatment of the anticipated wastewater
flows. The study will also determine whether the proposed individual on-site wells will provide safe water in
adequate quantity and quality.
Silver Spur Estates | 2.0 SITE INFORMATION 2
2.0 SITE INFORMATION
2.1 SITE LOCATION AND TOPOGRAPHY
The Silver Spur Estates subdivision is located in the low foothills on the east of Star Valley north of Bedford.
The area has gently sloping topography with a grade generally draining west to the Salt River. The project area
has no existing development and was previously used for agricultural purposes as irrigated pasture. There are
some single-family residences in the surrounding area, generally on lots of similar or smaller sizes. The Salt
River is approximately 3.5-miles to the west of the development.
2.2 HYDROGEOLOGIC SETTING
As shown on Figure 3, the proposed subdivision is located on an area of coalescing alluvial fans off the Salt
River Range to the east and the alluvial deposits associated with the floodplain of the Salt River. The
Quaternary-age alluvium in this area is generally composed of unconsolidated sand and gravel interbedded
with clay and silt (Forsgren Associates & Weston Engineering 2009). The bedrock beneath these
unconsolidated deposits is the Tertiary-age Salt Lake Formation. The Salt Lake Formation is a complex stack of
sedimentary rocks – sandstone, shale, and conglomerate – of widely variable hydrogeologic characteristics, up
to 1,000 ft thick (Miller et al., 1996). Figure 3 also shows the locations of all wells within one mile of the proposed
subdivision.
The Wyoming Water Development Commission (WWDC) funded a Well Construction and Testing Report for
the Town of Thayne in 1997. The report includes geologic and hydrologic data for Thayne Well No. 1
(P130958.0W) located in the NWSE Sec 24 T34N, R119W, approximately 2 miles west of the proposed
subdivision. At Thayne Well No. 1, the unconsolidated alluvial deposits were judged to be 20 ft. thick, and the
well is completed in the underlying Salt Lake Formation at a depth of 310 ft (Forsgren Associates, 1997). Another
WWDC report describes the Bedford Well No. 1 (P81829.0W) located approximately 2 miles to the south of the
proposed subdivision. The lithologic log of the Bedford Well No. 1 identifies alluvial deposits from the surface
to a depth of 102.5 ft and the well is completed in the underlying Salt Lake Formation at a depth of 310 ft
(Sunrise Engineering, 2019). A third WWDC groundwater study on the Star Valley Ranch includes details on a
test boring located in the SENE Sec 6 T34N, R118W approximately 2.8 miles northwest of the proposed
subdivision. In the WWDC test boring the unconsolidated alluvial deposits were judged to be 100 ft. thick
(Forsgren Associates & Weston Engineering, 2009). Underlying the alluvium, the boring penetrated the
underlying Salt Lake Formation to a depth of 492 ft. The degree of consolidation appears to have been the
primary distinction between the alluvium and the Salt Lake Formation. The WWDC lithologic descriptions are
best described penetrations near the proposed subdivision and are used as a reference for the general
stratigraphy and approximate thickness of formations in the region.
There are nearby water wells with lithologic logs that are located approximately 0.2 miles east (P30432.0W),
0.4 miles northeast (P150302.0W), 0.4 miles north (P154393.0W), and 0.4 miles northeast (P159511.0W) of the
proposed subdivision. The lithologic log from P30432.0W identifies gravel and clay layers consistent with
descriptions of alluvial material in the region from 0 to 240 ft where it encountered a layer of “solid rock”. The
lithologic log of P150302.0W identifies gravel consistent with descriptions of alluvial material in the region until
200 ft where it encountered “limestone”. The lithologic log of P154393.0W identifies gravel and clay layers
Silver Spur Estates | 2.0 SITE INFORMATION 3
consistent with descriptions of alluvial material in the region until 187 ft where the driller encountered
“limestone ledging”. The lithologic log of P159511.0W identifies clay and gravel to a depth of 200 ft which is
the total depth of the well. Well number P159511.0W does not appear to fully penetrate the alluvium; however,
in the other three wells the drillers all identified a rock layer that is likely the base of the alluvium. These wells
are closer to the proposed subdivision than the wells in the WWDC reports which may explain the thicker
alluvial deposits at that location. Due to their proximity to the proposed subdivision these wells have been
used as analogs for the thickness of the alluvium in the proposed subdivision.
Table 1 is a list of wells the Wyoming State Engineer’s Office (WSEO) classified as complete within half a mile
of the proposed subdivision. Appendix A contains a summary of permitted groundwater rights within one mile
of the proposed subdivision. A total of 37 complete groundwater permits are within one mile of the proposed
subdivision and 12 complete groundwater permits are within half a mile of the proposed subdivision.
The contact between the alluvial deposits and the underlying Salt Lake Formation is indistinct in this area as
both provide a complex interlayering of relatively unproductive clay layers and relatively productive gravel
lenses. None of the lithologic logs for the wells in Table 1 include explicit reference to the Salt Lake Formation.
Under locally favorable conditions, either unit has been found to support high-capacity wells. For the present
report, we assume the unconsolidated aquifer extends to a depth on the order of 200 ft beneath the proposed
subdivision. (Detailed distinction between the two units is not critical for the purposes of assessing water /
wastewater suitability for this project.)
In summary, the strata to serve as the water supply for the proposed subdivision consists of the unconsolidated
alluvial fan deposits off the mountains to the east, interlayered with the alluvial deposits of the Salt River, which
flows from south to north west of the proposed development. The underlying Salt Lake Formation provides a
potential deeper aquifer should the production of the overlying strata prove unsuitable at a specific location.
The unconsolidated deposits would also constitute the receiving strata for wastewater effluent from individual
septic systems.
Table 1 – Wells within Half of a Mile
2.3 SOIL TYPES
There is one major soil type present in the project area according to the NRCS Web Soil Survey
(https://websoilsurvey.nrcs.usda.gov) and Soil Survey of Star Valley (Soil Conservation Service, 1976). The major
Silver Spur Estates | 2.0 SITE INFORMATION 4
soil type is Huffine Silt Loam, 3 to 6 percent slopes (HuB). See Appendix B for the NRCS soils map of the project
area. The soils survey contains the following information regarding these soils.
Huffine Silt Loam, 3 to 6 percent slopes (HuB). The Huffine series consists of somewhat well-drained
soils that formed in wind-deposited silt or alluvium on alluvial fans. In a representative profile the
surface layer is brown silt loam about 7 inches thick. The upper part of the subsoil is brown silt loam
about 4 inches thick. The lower part of the subsoil is brown silty clay loam about 20 inches thick. The
substratum is brown very gravelly loamy sand to a depth of 60 inches or more. This gently sloping soil
is on alluvial fans. Permeability is moderate. Runoff is slow, and the hazard of erosion is slight. This soil
is used for irrigated crops, for range, and as wildlife habitat. The entire project area is in this soil type.
No other soil types are mapped in the project area.
2.4 AQUIFER CHARACTERISTICS
2.4.1 Depth to Groundwater, Aquifer Material and Flow Type
There are 12 complete groundwater permits within half a mile of the proposed subdivision (Table 1).
The depths to water reported for wells within a half a mile that are likely completed in the alluvium
(wells with a total depth of less than 200 ft) in the study area vary from 75 to 103 ft, with an average
depth to water of 86 ft. The water-bearing zones in these wells are universally described as “gravel”
and strata overlying the water-bearing zones (where identified on the lithologic log) are commonly
described as more clay rich.
Water flows westward towards the Salt River and the center of the basin. To some extent, the depth
to water in the alluvium is a function of proximity to the river, which is presumably the base elevation
for the local alluvial groundwater flow system. But the reported depths to water can vary greatly
depending on the depth at which the well is completed, the conditions under which the measurement
was taken (e.g. less than full recovery following testing), the season, and simple errors. These are not
quality-controlled data.
No information on seasonal variations of groundwater levels in the study area have been developed.
Given the normal cycles of recharge (including that provided by local flood irrigation), groundwater
highs are expected to occur in late summer and groundwater lows in late winter. As discussed above,
the variations in depth to water reported with domestic well completions are likely the result of a
combination of aquifer hydraulics and seasonal fluctuations.
The age and genesis of the alluvial deposits are consistent with the absence of known structures of
interest to the present study (e.g. faults, fracture zones, etc.). Nor are these deposits conducive to the
development of karst features. Groundwater flow will occur as flow through porous media, although
the permeability and porosity of individual strata will vary substantially.
2.4.2 Aquifer Thickness, Confinement & Surface Interaction
Subtraction of depths-to-water from total well depths calculate an average saturated interval of 81 ft
for the wells likely completed in the alluvium (with a total depth of less than 200 ft) within half a mile
of the proposed subdivision as shown in Table 1. As many of these wells do not fully penetrate the
alluvium, the full saturated thickness of the alluvial aquifer is likely greater than the calculated average,
Silver Spur Estates | 2.0 SITE INFORMATION 5
depending on local conditions. Additionally, the underlying Salt Lake Formation is saturated in the
area as well.
The clay and clay-rich layers discussed above likely serve as many local confining layers in the alluvial
aquifer. The alluvial deposits consist of a complex interbedding of sands, gravels and clays and
stratigraphic detail is insufficient to identify the lateral extent of such features. Pending more detailed
investigations, the overall aquifer is considered to be “semi-unconfined”. Surface recharge infiltrates
downward to eventually enter strata with useful water-bearing properties, but that process is likely
complex.
The vadose zone, through which recharge travels downward to reach the water table, is a mix of gravel,
sand, and clay strata, likely varying substantially in composition from place-to-place. The average
thickness of the unsaturated zone is 86 ft for the alluvial wells (less than 200 ft deep) listed in Table 1.
Interaction between surface and groundwater consists of the infiltration of local precipitation,
snowmelt, and irrigation water to recharge the aquifer, general groundwater flow direction is from
east to west, and discharges from the aquifer to the Salt River (including supplying riparian zone
evapotranspiration).
2.4.3 Transmissivity/Hydraulic Conductivity/Gradient/Porosity
In general, “permit yield” may or may not reflect actual measured production for domestic wells as
many domestic wells are limited to 25 gpm by the WSEO, but most of the values on Table 1 are
reported as “amount of water being pumped” on the Statements of Completion. The average of these
values is 20 gpm.
Some of the wells reviewed for which completion details were reported, are simply completed as
open-ended casings, rather than providing opportunity for groundwater to enter the well through
perforations or screen sections. This is an inexpensive approach that has proven adequate. It indicates
relatively high permeability in the final stratum in that sufficient water enters through the bottom of
the well.
Table 2 compiles the test data reported for which specific discharge rates and drawdown values were
reported with well completion forms. There were no reported pump tests with data for the wells
completed in the alluvium within 0.5 miles of the proposed subdivision therefore pump test data from
alluvial wells located within one mile were used. Transmissivity values are estimated using the pumping
rate, pumping time, and drawdown from the well completion reports. Driscoll (1986) developed
formulas to approximate the transmissivity for both confined and unconfined aquifers that are based
on generic assumptions about the aquifer and well test. Due to the quality of the data reported on
the well completion forms it is reasonable to use these assumptions and formulas to approximate the
transmissivity for these wells.
The “aquifer thickness” is poorly determined because the wells do not fully penetrate the alluvial
aquifer and all the wells in Table 2 are completed with open-ended casings. Listed in Table 2 is the
total thickness of the specific water-bearing stratum in which the well casing is open as reported as in
Silver Spur Estates | 2.0 SITE INFORMATION 6
the WSEO permit files. Due to the quality of the test data, and in the interest of conservatism the
parameters calculated in Table 2 are the minimums possible to produce the reported results.
In terms of productivity, these tests confirm that the alluvial aquifer is abundantly capable of meeting
the needs of individual residential lots. In terms of specific aquifer parameters, an average hydraulic
conductivity of at least 68.7 ft/day is indicated. There is a large variation in hydraulic conductivity (9-
301 ft/day). This variation is likely due to the variability of the aquifer itself, the well completion method,
and completion interval of the well.
Table 2 – Aquifer Test Data Extracted from WSEO Permit Files
Permit Number Rate
(gpm)
Drawdown
(ft)
Time
(hrs)
Specific
Capacity
(gpm/ft)
Transmissivity
(gpd/ft)
Aquifer
Thickness
(ft)
Hydraulic
Conductivity
(ft/day)
57641.0 12 1 1 12 18,000 30 80
90043.0 21 10 2 2 3,150 40 11
84049.0 10 1 2 10 15,000 40 50
84280.0 20 2 2 10 15,000 20 100
94289.0 10 10 2 1 1,500 23 9
91118.0 15 1 1 15 22,500 10 301
88550.0 12 1 3 12 18,000 30 80
40619.0 (Test 1) 25 10 2 3 3,750 13 39
40619.0 (Test 2) 20 5 3 4 6,000 13 62
41165.0 (Test 1) 30 13 2 2 3,462 38 12
41165.0 (Test 2) 30 14 4 2 3,214 38 11
Figure 4 is a potentiometric surface of the alluvium based on approximate groundwater elevations for
select wells for which the depth to water was reported upon well completion (dates and circumstances
vary) and for which the well has been located with sufficient accuracy to support estimation of surface
elevation. The former come from individual well Statements of Completion filed with the WSEO; the
latter are taken from topography maps.
Overall consideration of recharge/discharge relationships require that the groundwater gradient be
generally from east-to-west as precipitation and irrigation provide recharge across the aquifer and
regional groundwater discharge is to the Salt River. However, quantification of a meaningful gradient
is complicated by disparities in the reported data and the likely presence of multiple water-bearing
zones that are not fully integrated hydraulically. (There are both horizontal and vertical gradients in
the aquifer; lateral flow is being estimated using a composite horizontal gradient.)
A groundwater gradient is approximated by calculating an average gradient between sets of wells
shown on Figure 4. The average gradient from eight sets of wells at various locations on Figure 4 was
calculated to be 0.018 ft/ft.
Porosity of the saturated zone has not been directly assessed. An approximate value of 0.25 is
suggested based on the nature of the alluvial deposits (e.g. Sterrett, 2007).
Silver Spur Estates | 2.0 SITE INFORMATION 7
2.5 EXISTING WATER RIGHTS
2.5.1 Surface Water
A water right search was conducted for the development area. The proposed development has surface
water rights from Strawberry Creek by way of the Alto Canal Sprinkler Group Pipeline (previously Alto
Canal). Though the Hardman Canal crosses the northeast corner of the proposed development, no
surface water rights from the Hardman Canal are associated with the development area.
There is an existing Alto Canal line on the south side of the property. A water right distribution plan
proposes a lateral running north inside the right-of-way of the road to supply irrigation water to Lots
4-7. The Alto Canal company only wants one distribution point from their main line, so the developer
may run another lateral from this point for irrigation to Lots 1-3. The rights for areas within the
roadways will be either detached or abandoned. The proposed water right distribution map will be
filed with the Wyoming State Engineer’s Office.
2.5.2 Groundwater
There are no existing wells within the development boundary. Appendix A lists all groundwater rights
of record within one mile of the proposed subdivision.
Silver Spur Estates | 3.0 ON-SITE WASTEWATER SYSTEM ADEQUACY 8
3.0 ON-SITE WASTEWATER SYSTEM ADEQUACY
3.1 PERCOLATION RATES
Three percolation tests were performed within the proposed project area in September 2021. Refer to Figure
5 for test hole locations and Appendix B for percolation test data. The results from the three tests ranged from
0.77 to 4.5 min/inch. The maximum allowable percolation rate for Lincoln County is 1 min/inch and the
minimum allowable percolation rate is 60 min/inch. According to DEQ Chapter 25, Section 8I:
Coarse sand or soils having a percolation rate less than one (1) minute per inch (mpi) are unsuitable
for subsurface effluent disposal. These soils may be used if a one (1) foot layer of fine sand or loamy
sand is placed below the constructed soil absorption system. The soil absorption system shall be sized
based on the percolation rate of the fill material.
For this study, a percolation rate of 5 min/inch will be used. This assumes the use of a 1 foot layer of fill material
with a percolation rate of 5 min/inch.
Pits dug for percolation tests were at depths ranging from 4 ft to 6 ft. Also, an observation pit was dug to a
depth of 9.5 ft. No signs of groundwater were detected at these depths. Surrounding wells have recorded
static water levels at depths between 110 and 300 ft. With general slopes of 2-3% and minimum lot sizes of
about 2 acres, there should be no issue finding an acceptable location for a septic system on each lot.
3.2 LEACH FIELD SIZE
The size of leach field required for an on-site wastewater system depends upon the type of buildings it will
serve, the number of buildings, and the size of those buildings. It is anticipated the Silver Spur Estates
subdivision will be used for single-family residences. Lincoln County and DEQ regulations call for domestic
sewage flows of 150 gallons per day per bedroom for a single-family dwelling, with the flow declining slightly
for each additional bedroom. Also, the absorption system loading rate of 0.80 gallons per square foot per day
is given for the percolation rate. Given these values, Table 3 shows the required leach field area for a 2-, 3-, 4-
, 5-, or 6-bedroom system.
Table 3 - Required Leach Field Size
# of Bedrooms Peak Flow Rate (gpd) Req’d Leach Field Size (ft2)
2 280 350
3 390 488
4 470 588
5 550 688
6 630 788
Proposed lot sizes will range from 2.00-acres to 23.00-acres, with an average of about 5.03-acres per lot. Each
lot will have an individual standard septic tank with leach field. The minimum sized lot will be large enough to
accommodate the required leach field area as well as a replacement drain field area.
Silver Spur Estates | 3.0 ON-SITE WASTEWATER SYSTEM ADEQUACY 9
3.3 SEPARATION DISTANCES
Lincoln County and Wyoming DEQ requires the following separation distances:
From To Septic Tank To Absorption System
Wells (including neighbors) 50 100
Public Water Supply Well 100 200
Property Lines 10 10
Building Foundation (w/o foundation drains) 5 10
Building Foundation (w/ foundation drains) 5 25
Potable Water Pipes 25 25
Septic Tank -- 10
Stream or Surface Water (incl. intermittent) 50 50
Systems shall not be located beneath buildings, parking lots, roadways, or similarly compacted areas.
Each lot in the Silver Spur Estates subdivision will have an on-lot individual standard septic system. This
subdivision will have an average lot size of roughly 5.03 acres thereby meeting County requirements.
3.4 SHALLOW IMPERMEABLE LAYER
Lincoln County regulations state that an on-site small wastewater facility must be at least 4 ft above any
impermeable layer. Lithologic logs on the well Statement of Completion forms were obtained from the WSEO
for wells in the vicinity of the subdivision, and the data reviewed to determine if any impermeable layers were
present. There are no indications of a shallow impermeable layer according to the well logs.
Soil percolation rate tests were performed within subdivision boundaries, resulting in a rate of 0.77 to 4.5 min/
inch. A test pit was dug and observed in the development area to a depth of 9.5 ft. No impermeable layers
were observed.
Review of the nearby well logs, percolation test data, and project site shows no shallow impermeable layer
which will cause problems with leach field effluent.
3.5 SLOPE OF GROUND SURFACE
The proposed development is located within the low foothills of the lower Star Valley, previously used as
irrigated cropland. The slopes across the project area range between roughly 2% and 3% from east to west.
There will be no issues with siting of wastewater tanks and leach fields due to ground slope.
3.6 DEPTH TO GROUND WATER
Lincoln County and WDEQ regulations state that an on-site small wastewater facility must be at least 4 ft above
seasonally high ground water. No water was observed in the test pit to a depth of 9.5 ft. As mentioned in
Section 2.4.1, the average depth to groundwater is estimated at 86 ft.
3.7 AQUIFER IMPACTS
Water quality data for the aquifer receiving septic system effluent are provided in Appendix C. Both the
laboratory analysis and the widespread use of the alluvial aquifer for area drinking water identify the aquifer
as Class I under WDEQ regulations.
Silver Spur Estates | 3.0 ON-SITE WASTEWATER SYSTEM ADEQUACY 10
The impact of proposed individual wastewater disposal systems on the receiving aquifer has been evaluated
as per WDEQ Chapter 25, Appendices A and B.
3.7.1 WDEQ Appendix A Calculations
The DEQ Chapter 23 Appendix A cumulative nitrate loading analysis uses the following nitrogen mass
balance equation (Wehrmann Model):
𝐶𝑘 =(𝑉𝑎𝐶𝑎 + 𝑉𝑖𝐶𝑖 + 𝑉𝑟𝐶𝑟 − 𝑉𝑘𝐶𝑘)
(𝑉𝑎 + 𝑉𝑖 + 𝑉𝑟 − 𝑉𝑘)
where: Co = diluted concentration of NO3- as N leaving the subdivision
Vb = volume of groundwater entering the subdivision from up gradient area
Cb = ambient concentration of NO3- as N contained in the groundwater entering the
subdivision
Vi = volume of precipitation infiltrating beneath the subdivision
Ci = concentration of NO3- as N contained in the infiltrating precipitation
Vs = volume of septic effluent introduced beneath the subdivision
Cs = concentration of NO3- as N contained in the septic effluent
Vp = volume of groundwater pumped by wells beneath the subdivision
Cp = concentration of nitrate-nitrogen contained in the pumped groundwater
This analysis estimates the average nitrate concentration of groundwater following acceptance of
septic system leachate and subdivision precipitation recharge. The nitrate concentration of the septic
system effluent is diluted by infiltrating precipitation and groundwater flow beneath the proposed
subdivision to produce a lower nitrate concentration at the subdivision boundary.
The value of Vb is calculated using an average hydraulic conductivity of 68.7 ft/day or 513 gpd/ft2
(from Section 2.4.3), an aquifer width measured as the cross-section perpendicular to east-to-west
groundwater flow (1,306 ft), an effective aquifer thickness of 81 ft (saturated thickness in Section 2.4.2),
and an aquifer gradient of 0.018 ft/ft. Thus, the value of Vb is:
𝑉𝑎 = 513𝑎𝑘𝑎
𝑎𝑟2 × 1,306 𝑎𝑟× 81 𝑎𝑟× 0.018 𝑎𝑟
𝑎𝑟=976,828 𝑎𝑘𝑎
The value of Cb is taken as 0.27 mg/L from the Allred Well sample results (Appendix C).
Precipitation also dilutes the concentration of nitrate from the septic system effluent. Precipitation
input is estimated as the infiltration rate (ft/day) of precipitation multiplied by the subdivision area (ft2).
The proposed subdivision is approximately 35.22 acres, or 1,534,000 ft2. The mean annual precipitation
is 23.57 inches. The percentage of total precipitation that reaches the aquifer varies widely as a function
of precipitation patterns (both spatial and temporal), the characteristics of the surface, competition
from vegetation, evaporation, and runoff, etc. Estimates commonly fall in the 5 - 10% range. Assuming
a generic 5% of precipitation infiltrates the aquifer to be conservative, the value of Vi is:
𝑉𝑖 = (0.05 × 23.57 𝑖𝑘.
𝑦𝑟× 1 𝑎𝑟
12 𝑖𝑘.× 1 𝑦𝑟
365 𝑎𝑎𝑦𝑟)× 1,534,000 𝑎𝑟2 × 7.48 𝑎𝑎𝑘
1 𝑎𝑟3 = 3,087 𝑎𝑘𝑎
The value of Ci is assumed to be 0.05 mg/L (WDEQ Chapter 23 default worksheet value).
Silver Spur Estates | 3.0 ON-SITE WASTEWATER SYSTEM ADEQUACY 11
The value of Vs is the product of the effluent recharge per lot and the number of lots. The effluent
recharge is taken as 300 gpd/unit (WDEQ Chapter 23 default value for three-bedroom homes). The
value of Vs is:
𝑉𝑟=300 𝑎𝑘𝑎 × 7 𝑘𝑘𝑟𝑟=2,100 𝑎𝑘𝑎
The value of Cs is assumed to be 40 mg/L (WDEQ Chapter 23 default value for conventional septic
systems).
The daily volume of groundwater pumped by wells beneath the subdivision is calculated in Table 4
(Section 4.1) and we assume landscape water will be provided from the domestic-supply wells.
Therefore, the value of Vp is calculated as 6,300 gpd.
Similar to the value of Cb, the value of Cp is taken as 0.27 mg/L from the Allred Well sample results
(Appendix C).
Thus, the value of Co leaving the subdivision area at the down-gradient property boundary is:
𝐶𝑘 =976,828 × 0.27 +3,087 × 0.05 +2,100 × 40 –6,300 × 0.27
976,828 +3,087 + 2,100 – 6,300 = 0.35 𝑘𝑎/𝐿
Sensitivity Analysis. The calculated nitrate concentration is obviously sensitive to the accuracy of the
input parameters. While we have developed our estimates based on the available information, as
detailed above, many of the relevant parameters are only approximately known for this site. The
following sensitivity analysis indicates the conclusion that the diluted nitrate concentration will be less
than the 10 mg/L limit at the down-gradient boundary is robust.
The nitrate balance is dominated by the calculated groundwater flux through the alluvial aquifer.
The least well-constrained parameter in that calculation is the permeability of the portion of the
aquifer into which septic system effluent will be introduced. Application of a 50% lower hydraulic
conductivity value (257 gpd/ft2) increases the calculated Co to 0.44 mg/L.
The percentage of precipitation that infiltrates to recharge groundwater is rarely well constrained.
Increasing the percentage of precipitation to 10% (all other parameters as in the base case)
produces no net effect, i.e., a calculated Co value of 0.35 mg/L.
3.7.2 WDEQ Appendix B Calculations
The calculations presented in WDEQ Chapter 23, Appendix B provide estimates for the vertical travel
time from a leach field to the water table and the distance leachate arriving at the groundwater table
will travel horizontally over any remaining time within a total period of two years.
Vertical Travel Time. The Appendix B analysis uses the following equation to calculate vertical travel
time:
𝑟1 =𝑑×𝜃
0.5×𝛼
where: t1 = vertical travel time in years
Silver Spur Estates | 3.0 ON-SITE WASTEWATER SYSTEM ADEQUACY 12
d = depth to groundwater in cm
θ = volumetric soil moisture
α = total recharge (effluent + precipitation in cm/yr)
The value of d is taken as 86 feet (2,621 cm) from Table 1.
The value of θ is assumed to be 0.321 mL/cm3 from Chapter 23, Appendix B, for “sandy clay”, the
default value, the description for which is reasonably consistent with the driller logs of the alluvial
deposits (see attached Statements of Completion in Appendix A).
The required soil absorption infiltration area for a three-bedroom home is 488 ft2, as presented in
Table 3. The total annual effluent discharge per individual system is estimated as:
3 𝑎𝑎𝑎𝑟𝑘𝑘𝑘𝑟 × 100 𝑎𝑘𝑎
𝑎𝑎𝑎𝑟𝑘𝑘𝑘 × 365𝑎𝑎𝑦𝑟
𝑦𝑟 × 1 𝑎𝑟3
7.48 𝑎𝑎𝑘=14,639 𝑎𝑟3
𝑦𝑟
Across the area of the individual leach field, the effluent recharge to the aquifer in inches per year is
thus:
(14,639 𝑎𝑟3/488 𝑎𝑟2 )× 12 𝑖𝑘.
𝑎𝑟 = 360 𝑖𝑘.
To calculate total flux into the aquifer through the leach field footprint, 5% of the average annual
precipitation is added to the effluent volume. The average annual precipitation is 23.75 inches
(discussed above). Therefore, the value of α is:
𝛼=(360 𝑖𝑘.
𝑦𝑟+0.05 × 23.57 𝑖𝑘.
𝑦𝑟)(2.54 𝑎𝑘
𝑖𝑘.)=917 𝑎𝑘
𝑦𝑟
Thus, the value of t1 is:
𝑟1 =
2,621 𝑎𝑘× 0.321 𝑘𝐿
𝑎𝑘3
0.5 × 917 𝑎𝑘
𝑦𝑎𝑎𝑟
= 1.83 𝑦𝑎𝑎𝑟𝑟
Because the vertical travel time is less than two years, the horizontal distance the leachate will migrate
will need to be calculated.
Horizontal Travel Distance. The horizontal travel distance is a function of horizontal travel time and
horizontal linear velocity as follows:
𝑋= 𝑟2 × 𝑣
where: X = minimum allowable isolation distance
t2 = horizontal travel time
v = average groundwater linear velocity
The value of t2 is calculated as follows:
𝑟2 = 2 𝑦𝑟−𝑟1
Silver Spur Estates | 3.0 ON-SITE WASTEWATER SYSTEM ADEQUACY 13
where: t1 = vertical travel time in years (calculated above)
t2 = horizontal travel time
Thus, the value of t1 is:
𝑟1 =2 𝑦𝑟−1.83 𝑦𝑟 = 0.17 𝑦𝑟× 365 𝑎𝑎𝑦𝑟
𝑦𝑟= 62 𝑎𝑎𝑦𝑟
The value of v is calculated per WDEQ Chapter 23 Appendix B as follows:
𝑣 = 𝑘 × 𝑖 / 𝑘
where: v = average groundwater linear velocity
k = hydraulic conductivity (permeability) of the saturated aquifer (ft/day)
i = hydraulic gradient (ft/ft)
n = effective porosity (dimensionless)
The values of k and i were determined above as 68.7 ft/day and 0.018 ft/ft, respectively. The value of
n is estimated at 0.15 based on the specific yield value for gravel with clay layers identified in the USGS
report titled Specific Yield – Compilation of Specific Yields for Various Materials (Johnson 1967). Thus,
the value of v is:
𝑣 =(68.7 𝑎𝑟
𝑎𝑎𝑦× 0.018 𝑎𝑟
𝑎𝑟)÷ 0.15 = 8.24 𝑎𝑟
𝑎𝑎𝑦 = 3,009 𝑎𝑟
𝑦𝑟
Thus, the value of X for the remaining travel time of 0.17 years is:
𝑋= 62 𝑎𝑎𝑦𝑟× 8.24 𝑎𝑟
𝑎𝑎𝑦= 511 𝑎𝑟
To maintain a 2-year travel window from the subdivision boundary, it may be prudent to site septic
system leach fields towards the eastern portions of the westernmost lots in the proposed subdivision.
(Those lots are 560 feet “deep” in the direction of groundwater flow.)
3.7.3 WDEQ Appendix C Calculations
WDEQ Chapter 23 Appendix C calculations are provided to assess potential impacts to public drinking
water supply wells. Based on data from the U.S. Environmental Protection Agency (EPA) Drinking Water
Watch website (2022), there are no public drinking water supply wells nearer than two miles from the
proposed subdivision. The Thayne Well No. 1 (P130958.0W) is located approximately two miles west
of the proposed subdivision and the lithologic log for the well states that the well is completed in the
Salt Lake Formation. The well draws water from both screened and open hole completions from
between 143 and 310 feet deep, i.e., starting 57 feet below the groundwater table. The well also has a
reported static water level of 27.7 ft which indicates that the aquifer it is completed in is confined. The
Bedford Well No. 1 (P81829.0W) located approximately 2 miles to the south of the proposed
subdivision is completed in the Salt Lake Formation and is distinctly not down gradient of the proposed
subdivision. Based on the distance from the proposed subdivision, location, lithology, depth-of-
completion, and the Cumulative Nitrate Loading Analysis calculated above, we do not consider these
Silver Spur Estates | 3.0 ON-SITE WASTEWATER SYSTEM ADEQUACY 14
wells to be at risk of contamination from the wastewater disposal facilities of the proposed subdivision
and no calculations are indicated under the appendix.
3.8 WASTEWATER CONCLUSIONS & RECOMMENDATIONS
The proposed Silver Spur Estates subdivision consists of 7 single-family residential lots. The lots will have a
minimum acreage of approximately 2.00-acres and will average 5.03-acres each. Each lot will utilize an on-site
wastewater system (standard septic system and leach field) and an individual on-site well. The Lincoln County
regulations for minimum lot size will be met. There will be adequate building space available at each site for
construction of a leach field and replacement leach field while still meeting the required separation distances
and slope requirements.
According to WDEQ Rules & Regulations Chapter 25 Section 2, soil absorption systems with a soil percolation
rate less than 5 min/inch require an application sealed and signed by a professional engineer. The highest
percolation rate recorded was 4.5 min/inch. Therefore, all wastewater systems within the subdivision will require
approval by a professional engineer.
The soils in this subdivision have percolation rates which suggest wastewater will receive adequate treatment
and will not create surfacing problems. It is not anticipated shallow impermeable layers or groundwater depth
will cause problems with individual on-site wastewater systems. The topography is gently sloping with a general
grade of 2% to 3%.
The cumulative nitrate loading analysis indicated the impact due to the subdivision will be under the nitrate
threshold of 10 mg/L set by DEQ. Use of individual on-lot standard septic systems will be allowed. No off-site
public water wells are located where there is potential for contamination from the proposed subdivision.
Risk of groundwater contamination appears to be low due to the low density of the development and soils
that will allow for adequate treatment of the wastewater with adequate setbacks. The groundwater flux through
the alluvial aquifer will extensively dilute any impact from the wastewater systems. The geology of the area and
characteristics of the aquifer indicate use of individual on-lot wastewater systems is appropriate.
Silver Spur Estates | 4.0 ON-SITE WATER SYSTEM ADEQUACY
15
4.0 ON-SITE WATER SYSTEM ADEQUACY
4.1 DESIGN CONSIDERATIONS
The Silver Spur Estates subdivision will have a build-out of 7 lots for single-family residential use. Water
demands for the subdivision will be served by individual on-site wells capable of design flows of 10-gpm or
900-gpd per lot. Details for estimated water usage can be found in Table 4.
Table 4 - On-Lot Water Requirements
Lot #’s Type Water System Average Day
Use (gpd)
Peak Day
Use (gpd)
1 - 7 Single-Family
Residential Individual On-site Wells 6,300 17,136
There are no existing wells located within the proposed subdivision area. However, as listed in Table 1 and
compiled in Appendix A, domestic-supply wells in the immediate area are commonly permitted for flows in
excess of 10 gpm. Reported yields for the Table 1 wells less than 200-ft deep (i.e. presumably completed in the
alluvial aquifer) average 15-gpm. The highest reported yield is 1,200-gpm for an irrigation well. (The peak-day
demand listed in Table 4 averages 1.7-gpm.)
4.2 WATER QUALITY
Owner-reported assessments of the water quality from the aquifer available to host individual domestic wells
for the proposed subdivision are uniformly “good” (which is the highest ranking available on the reporting
form). Specific water quality data are provided for a 2022 sample from the David Allred well (about 2,300-ft
north of the proposed subdivision border) in Appendix C. Both the laboratory analysis and the widespread use
of the alluvial aquifer for area drinking water demonstrate its suitability.
Potential sources of contamination of the aquifer consist of on-site septic systems and the inherent exposure
to surface application and accidental release of the various chemicals associated with residential living. In
addition, the area is in the midst of agricultural lands, exposing the shallow aquifer to recharge potentially
including agricultural chemicals. The potential impact of local wastewater disposal facilities with respect to
nitrate concentrations is evaluated above.
4.3 WATER SYSTEM CONCLUSIONS & RECOMMENDATIONS
The proposed Silver Spur Estates subdivision consists of 7 lots, with an average lot size of 5.03 acres and a
minimum lot size of roughly 2.00 acres. Single-family residential lots will utilize individual on-lot wells. Lincoln
County regulations for minimum lot size for subdivisions will be met.
Water quality testing indicates the water is safe for domestic purposes. Data from area wells indicate that
adequate water will likely be available from the on-site wells. The results of this study indicate that the use of
individual on-lot wells to serve the Silver Spur Estates Subdivision is appropriate.
Silver Spur Estates | 5.0 REFERENCES 16
5.0 REFERENCES
Driscoll, F.G., 1986. Groundwater and Wells, Second Edition, p 1021. Empirical equations used to estimate
specific capacity and transmissivity.
Forsgren Associates, Inc., (August 1997) Well Construction and Testing Report Level II Feasibility Study Thayne,
Wyoming. Prepared for Wyoming Water Development Commission.
Forsgren Associates & Weston Engineering (February 2009). Star Valley Ranch Groundwater Level II Study;
consultant report for Wyoming Water Development Commission
Larsen, M.C., LaForge, J.S., and Wittke, S.J., 2015, Surficial geologic map of the Afton 30' x 60' quadrangle,
Sublette and Lincoln counties, Wyoming: Wyoming State Geological Survey Open File Report 15-9,
scale 1:100,000.
Miller, Cheryl A., Maria Plafcan, and Melanie L. Clark. 1996. Water Resources of Lincoln County, Wyoming; U.S.
Geological Survey Water-Resources Investigations Report 96-4246.
Natural Resources Conservation Service, U. (March 1976). Soil Conservation Service.
Soil Survey. (2021, October 27). Natural Resources Conservation Service, United States Department of
Agriculture. Retrieved from Web Soil Survey: https://websoilsurvey.nrcs.usda.gov/app/
Sterrett, Robert. 2007. Groundwater & Wells; Johnson Screens, third edition, p. 19 (approximate average value
from Table 2.1 for “sand & gravel mix”).
Sunrise Engineering, (October 2019) Bedford Water Supply Level I Master Plan. Prepared for Wyoming Water
Development Commission.
U.S. Environmental Protection Agency. 2022. Drinking Water Watch, Public Water Supply Systems Search. EPA
Region 8. < https://sdwisr8.epa.gov/Region8DWWPUB/index.jsp>
Wyoming Department of Environmental Quality. (July 2012). Water Quality Rules and Regulations Chapter 23.
Wyoming Department of Environmental Quality. (July 2012). Water Quality Rules and Regulations Chapter 25.
FIGURES
www.sunrise-eng.com
AFTON, WYOMING 83110
47 EAST 4TH AVENUE
TEL 307.885.8500 Z FAX 307.885.8501
ENGINEERING
DESIGNED BY: RVH
DRAWN BY: LKF
DATE: 03/09/2021
FIGURE: 1
FIGURE 1 - SILVER SPUR ESTATES
PROJECT AREA VICINITY MAP
LOCATED IN SECTION 20, T34N R118W
LINCOLN COUNTY, WYOMING
ORTHN
45
6
7 9
16
1718
19 20 21
30
1
12
13
24
25
R. 118 W.
T.
34
N.
P182556.0W
P30432.0W
P64159.0W
P154393.0WP165648.0W
P204831.0W
P183764.0W
P175293.0W
P150302.0W
P172831.0W
P212180.0W
P159511.0W
P157203.0W
P175012.0W
P204545.0W
P204201.0W
P206788.0W
P180975.0W
P168154.0W
P103204.0W
P147046.0W
P75547.0W
P170580.0W
P98330.0W
P72334.0W
P167762.0W
P41165.0W
P40619.0WP84280.0W
P94289.0WP136131.0W
P119433.0W
P91118.0WP88550.0W
P84049.0W
P57641.0WP49279.0W
P166828.0W6025605060756100612561506175 6
2
0
0
6
2
2
5
6
2
5
0
6025605060756100
6125615061756200
6
2
5
0
6
2
7
5
63
0
0
63256350P47186.0W
P108182.0W
P38915.0W
P38915.0W
P30432.0W
P215144.0W P213605.0W
P185203.0W SUBDIVISION BOUNDARY
1 MILE BUFFER BOUNDARY
Alluvium and Slopewash (as)
Alluvial fan and alluvial deposits (fa)
Landslide Deposits (l)
Residuum and Slopewash (rRs)
Residuum and bedrock outcrops (rsR)
Slopewash and Residuum (sRr)
P61107.0W
LEGEND
Water Well Permit Number
\\wwc.local\work\Sheridan\Sunrise Engineering\2022032 Sunrise Engineering Chapter 23 Reports\05CAD\Sheets\SILVER SPUR ESTATES.dwg 11/1/2022 3:56:37 PM jackie m. carswell
0 1/2 1
GRAPHIC SCALE (MILES)
SILVER SPUR ESTATES
LINCOLN COUNTY, WYOMING
FIGURE 3:
SURFICIAL GEOLOGY
W ENGINEERINGWC
PREPARED BY:
1849 TERRA AVE.
SHERIDAN, WY 82801
17
19 20
6088P103204.0W 6045P204545.0W
6062P183764.0W
6037P175293.0W
6026P150302.0W
6046P204831.0W
6014P212180.0W
6027P157203.0W
6030P172831.0W
6042P206788.0W
6033P147046.0W
6058P180975.0W
6090P175012.0W
6041P168154.0W 6042P167762.0W 6006P170580.0W
6083P61107.0W
6055P96625.0W
6206P75547.0W
R. 118 W.
T.
34
N.60756100612561506175620062256250627563006325635063756400624062006120608060406160608060406200612061606240SUBDIVISION BOUNDARY
1 MILE BUFFER BOUNDARY
6083P61107.0W
LEGEND
Water Well Permit Number
Static Water Elevation
Potentiometric Surface Contour (40' Interval)
Potentiometric Surface Contour (Inferred)
Ground Surface Contour (5' Interval)
\\wwc.local\work\Sheridan\Sunrise Engineering\2022032 Sunrise Engineering Chapter 23 Reports\05CAD\Sheets\SILVER SPUR ESTATES.dwg 11/1/2022 3:56:37 PM jackie m. carswell
W ENGINEERINGWC
0 1/8 1/4
GRAPHIC SCALE (MILES)
SILVER SPUR ESTATES
LINCOLN COUNTY, WYOMING
FIGURE 4:
POTENTIOMETRIC SURFACE
PREPARED BY:
1849 TERRA AVE.
SHERIDAN, WY 82801
www.sunrise-eng.com
AFTON, WYOMING 83110
47 EAST 4TH AVENUE
TEL 307.885.8500 Z FAX 307.885.8501
ENGINEERING
DESIGNED BY: RVH
DRAWN BY: LKF
DATE: 11/17/2022
FIGURE 5 - SILVER SPUR ESTATES
PERCOLATION TEST LOCATIONS
LOCATED IN SECTION 20, T34N R118W
LINCOLN COUNTY, WYOMING
ORTHN
APPENDIX A – WELL PERMIT DATA WITHIN ONE MILE AND SELECT
WELL STATEMENTS OF COMPLETION
PERMIT PRIORITY STATUS OWNER FACILITY NAME USES TWN RNG SEC QTR-QTR
PERMIT
YIELD
(gpm)
TOTAL
DEPTH
(ft)
STATIC
DEPTH
(ft)
PWBF
Top
(ft)
PWBF
Bottom
(ft)
P101244W 01/16/1996 Complete SHARON BARTHOLOMEW BARTHOLOMEW WELL #1 DOM_GW 034N 118W 16 NW1/4SE1/4 20 505.00 348 450 500
P108182W 09/26/1997 Complete ROBERT P/JENNIFER M GIESE LONE STAR #1 DOM_GW; STK 034N 118W 16 SW1/4SE1/4 25 500.00 335 440 500
P102561W 06/03/1996 Cancelled ELLEN HEINER CHARLES G HEINER #1 DOM_GW; STK 034N 118W 16 NW1/4SW1/4 25
P50308W 09/20/1979 Cancelled CHARLES HEINER CHAS-HEINER #1 IRR_GW 034N 118W 16 NW1/4SW1/4 1200
P60885W 05/17/1982 Cancelled David H. & Susan B. Day DAY #1 DOM_GW; STK 034N 118W 16 SW1/4NE1/4 25
P103204W 08/05/1996 Complete LESTER BARBER FAMILY TRUST B&B #1 DOM_GW 034N 118W 17 SW1/4SW1/4 22 140.00 80 100 140
P150302W 04/10/2003 Complete MICHAEL S. HOLCOMB & RUTH
A. BESS
HOLCOMB 1 DOM_GW 034N 118W 17 NE1/4SW1/4 15 240.00 180 220 240
P154393W 10/10/2003 Complete RANDAL & DIANA HILL HILL #1 DOM_GW 034N 118W 17 NW1/4SE1/4 25 300.00 187 240 300
P157203W 03/25/2004 Complete JOHN SCOTT & KAREN K BARBER LOVEY 1 DOM_GW 034N 118W 17 NW1/4SW1/4 15 200.00 140 180 200
P159511W 06/14/2004 Complete BRAD & MONICA BARFUSS BARFUSS #1 DOM_GW 034N 118W 17 NE1/4SW1/4 25 200.00 75 163 200
P165648W 03/10/2005 Complete ROBERT AND JUDITH GONET GONET #1 DOM_GW 034N 118W 17 NW1/4SE1/4 15 265.00 200 260 265
P170281W 10/27/2005 Abandoned WILKES FAMILY TRUST WILKES TRUST WELL DOM_GW; STK 034N 118W 17 SE1/4SE1/4 25
P172831W 01/23/2006 Complete LINDA BUTTERFIELD BUTTERFIELD #1 DOM_GW 034N 118W 17 NW1/4SW1/4 20 230.00 150 220 230
P175293W 06/16/2006 Complete EDWARD LOWERY LOWERY #1 DOM_GW 034N 118W 17 NE1/4SW1/4 20 240.00 180 235 240
P183764W 11/13/2007 Complete RAYMOND AND GLORIA HINTZE HINTZE #1 DOM_GW 034N 118W 17 NW1/4SE1/4 20 240.00 180 235 240
P204545W 09/14/2015 Complete DONALD AUSTIN AUSTIN #1 DOM_GW;STK 034N 118W 17 SW1/4SW1/4 10 160.00 103 120 147
P204831W 11/06/2015 Complete SCOTT BALK BALK #1 DOM_GW 034N 118W 17 NE1/4SW1/4 20 242.00 180 220 242
P207577W 07/07/2017 Complete DAVID ALLRED LOST CREEK STABLES DOM_GW;STK 034N 118W 17 NW1/4SE1/4 20 300.00 217 232 310
P209113W 06/05/2018 Complete KENT FULLER SHOP WELL DOM_GW; STK 034N 118W 17 NW1/4SW1/4 10 220.00 121 180 210
P212180W 04/22/2020 Complete QUINN AND DIANA HEINER Q & D HEINER #1 DOM_GW 034N 118W 17 NW1/4SW1/4 20 220.00 170 200 220
P212443W 05/30/2020 Incomplete GREGORY L FLESHMAN HOME DOM_GW 034N 118W 17 SW1/4SE1/4 25 180.00 110 160 180
P212552W 06/17/2020 Incomplete BRIAN AND HEIDI ROBISON ROBISON #1 DOM_GW;STK 034N 118W 17 NE1/4SW1/4 25
P215646W 09/22/2021 Incomplete CORY THOMAS LAJINESS THOMAS 1 DOM_GW 034N 118W 17 NW1/4SW1/4 25
P72334W 04/21/1986 Complete EDNA QUINN QUINN #1 DOM_GW 034N 118W 17 NE1/4NE1/4 10 115.00 58 -1 -1
P75547W 09/11/1987 Complete JACK ELLIS ELLIS #1 DOM_GW 034N 118W 17 NE1/4NE1/4 5 134.00 70 70 90
P136587W 07/19/2001 Cancelled JOSEPH GEORGE STANEK II /
CHRISTY ANN JOHNSON
STANEK # 1 DOM_GW 034N 118W 18 SE1/4NE1/4 25
P147046W 09/17/2002 Complete BRIAN J. ROBERTSON FLYING J DOM_GW 034N 118W 18 SW1/4NE1/4 15 135.00 80 130 135
P167762W 05/20/2005 Complete STEVEN & DEBORAH CAPPS 4-C RANCH DOM_GW; STK 034N 118W 18 NW1/4NE1/4 25 100.00 60 90 100
P168154W 06/08/2005 Complete JOYCE BARKER ECHO DOM_GW 034N 118W 18 NE1/4NE1/4 20 140.00 100 135 140
P175012W 05/22/2006 Complete NADINE EDWARDS E #1 DOM_GW 034N 118W 18 NE1/4NE1/4 25 180.00 60 140 180
P180975W 03/14/2007 Complete TREVOR KUNZ #0501 DOM_GW 034N 118W 18 SE1/4NE1/4 15 140.00 80 139 140
January 27, 2022 Groundwater Rights within One Mile of Silver Spur Estates Page 1 of 3
PERMIT PRIORITY STATUS OWNER FACILITY NAME USES TWN RNG SEC QTR-QTR
PERMIT
YIELD
(gpm)
TOTAL
DEPTH
(ft)
STATIC
DEPTH
(ft)
PWBF
Top
(ft)
PWBF
Bottom
(ft)
P204201W 07/21/2015 Complete TROY AND KELSEY JANSEN SNAPPY 1 DOM_GW 034N 118W 18 NE1/4NE1/4 18 158.00 95 95 158
P206788W 02/21/2017 Complete FREDRICK AND MEGAN
JOHNSON
JOHNSON #1 DOM_GW;STK 034N 118W 18 SE1/4NE1/4 25 143.00 85 85 143
P213860W 02/08/2021 Incomplete JEFF AND ROBYN KILROY HAYSTACK MOUNTAIN RANCH
LOT 4
DOM_GW 034N 118W 18 NW1/4NE1/4 25
P98330W 02/08/1995 Complete JOHN D. & CONNIE CHRISTINE
ROBERTSON
V=2 DOM_GW; STK 034N 118W 18 SW1/4NE1/4 15 120.00 100 100 120
P119433W 10/06/1999 Complete CLINT/CALLY MULLENDORE KAL 1 DOM_GW 034N 118W 19 NW1/4NE1/4 20 80.00 50 50 80
P136131W 07/03/2001 Complete SHELLY R. MARTINEZ MARTINEZ # 2 DOM_GW 034N 118W 19 SW1/4NE1/4 15 80.00 30 30 80
P166828W 04/11/2005 Complete CHRISTINE BOOKER CHRIS #1 DOM_GW 034N 118W 19 SW1/4NE1/4 15 70.00 40 60 70
P213605W 12/09/2020 Incomplete BARRY KENDALL KENDALL WELL DOM_GW 034N 118W 19 NW1/4NE1/4 25
P215144W 07/30/2021 Incomplete RONALD AND KIMBERLY P
MORSE
R AND K MORSE DOM_GW 034N 118W 19 NW1/4NE1/4 25
P37135W 04/08/1977 Cancelled VAN H. & THELMA DANA DANA #1 DOM_GW 034N 118W 19 SW1/4NE1/4 25
P40348W 10/06/1977 Cancelled VAN H. & THELMA DANA DANA #2 DOM_GW 034N 118W 19 NW1/4NE1/4 25
P40619W 10/18/1977 Complete JAMES F. ALTMAN TRIPLE J #1 DOM_GW; STK 034N 118W 19 SW1/4NE1/4 15 93.00 67 80 93
P41165W 10/20/1977 Complete QUIENTON L. & BARBARA K.
NEWMAN
NEWMAN #1 DOM_GW 034N 118W 19 NW1/4NE1/4 12 100.00 40 65 103
P49279W 07/24/1979 Complete DOUGLAS REYNOLDS REYNOLDS #1 DOM_GW; STK 034N 118W 19 NW1/4NE1/4 15 80.00 50 65 80
P57641W 07/24/1981 Complete ARLAN VAN HUYSEN HUYSEN #1 DOM_GW 034N 118W 19 NW1/4NE1/4 12 80.00 50 50 80
P74519W 04/28/1987 Complete BRENDA GOODNIGHT GOODNIGHT #1 DOM_GW 034N 118W 19 SW1/4NE1/4 10 94.00 62 73 91
P75138W 07/02/1987 Cancelled JOHN D. & CONNIE CHRISTINE
ROBERTSON
V 1 DOM_GW 034N 118W 19 NW1/4NE1/4 25
P84049W 11/21/1990 Complete JOHN D. & CONNIE CHRISTINE
ROBERTSON
ROBERTSON 1 DOM_GW 034N 118W 19 NW1/4NE1/4 10 80.00 50 40 80
P84280W 01/15/1991 Complete BRAD DANA DANA #1 DOM_GW 034N 118W 19 SW1/4NE1/4 20 91.00 70 70 90
P88550W 06/22/1992 Complete CLAUDIA E. GETTY GETTY 1 DOM_GW 034N 118W 19 SW1/4NE1/4 12 80.00 50 50 80
P91118W 03/29/1993 Complete SHELLY R. MARTINEZ MARTINEZ 1 DOM_GW 034N 118W 19 SW1/4NE1/4 15 80.00 60 70 80
P94289W 12/23/1993 Complete BRAD DANA DANA #2 DOM_GW 034N 118W 19 SW1/4NE1/4 10 83.00 60 60 83
P38915W 07/12/1977 Complete LYLE T. FRASIER FRASIER #1 DOM_GW; STK 034N 118W 19 NW1/4SE1/4 23 110.00 55 51 59
P90043W 11/12/1992 Complete JAMES P. TAYLOR TAYLOR #1 DOM_GW 034N 118W 19 SE1/4SE1/4 20 90.00 50 50 90
P104739W 01/02/1997 Cancelled Wyo State Water Development
Commission
THAYNE TEST BORING #3 TST 034N 118W 20 NW1/4SW1/4 0
P30432W 07/07/1975 Complete DOUGLAS LYLE JENKINS JENKINS #1 DOM_GW 034N 118W 20 NE1/4NE1/4 25 371.00 300 340 371
P64159W 05/18/1983 Complete JOAN STEWART STEWART #1 DOM_GW 034N 118W 20 SE1/4NE1/4 22 304.00 263 280 310
P118698W 09/15/1999 Complete LESTER K/VICKIE JEPPERSON JEPPERSONS #1 DOM_GW 034N 118W 21 NE1/4NE1/4 25 600.00 300 570 580
P122003W 01/21/2000 Complete James/Judy Speck Bucko #1 DOM_GW 034N 118W 21 NE1/4NE1/4 25 280.00 200 240 280
January 27, 2022 Groundwater Rights within One Mile of Silver Spur Estates Page 2 of 3
PERMIT PRIORITY STATUS OWNER FACILITY NAME USES TWN RNG SEC QTR-QTR
PERMIT
YIELD
(gpm)
TOTAL
DEPTH
(ft)
STATIC
DEPTH
(ft)
PWBF
Top
(ft)
PWBF
Bottom
(ft)
P179999W 03/05/2007 Cancelled LON H. AND KAREN L. LUND FOX CREEK DOM_GW; STK 034N 118W 21 SW1/4NE1/4 0 400.00 342 360 400
P182556W 07/26/2007 Complete BEDFORD PROPERTIES, LLC BEDFORD PROPERTIES #1 DOM_GW; STK 034N 118W 21 NW1/4NE1/4 25 460.00 390 448 460
P209483W 07/31/2018 Complete JORDAN MILLER FOX CREEK DOM_GW;STK 034N 118W 21 SW1/4NE1/4 20 400.00 342 360 400
P40391W 09/07/1977 Cancelled J. H. MERRITT J H MERRITT #1 DOM_GW 034N 118W 21 NW1/4NW1/4 25
P47186W 04/02/1979 Complete RANDALL L. JENSEN SKINNER WELL #1 DOM_GW 034N 118W 21 SW1/4SW1/4 20 240.00 30 218 240
P70790W 07/26/1985 Cancelled LAGRANDE MERRITT MERRITT #1 DOM_GW; STK 034N 118W 21 SE1/4NW1/4 25
January 27, 2022 Groundwater Rights within One Mile of Silver Spur Estates Page 3 of 3
APPENDIX B – SOIL MAP, SOIL MAP UNIT DESCRIPTION REPORT, AND
PERCOLATION TEST DATA
9
Custom Soil Resource Report
Soil Map
4751980475205047521204752190475226047523304752400475247047519804752050475212047521904752260475233047524004752470504620 504690 504760 504830 504900 504970
504620 504690 504760 504830 504900 504970
42° 55' 30'' N 110° 56' 37'' W42° 55' 30'' N110° 56' 19'' W42° 55' 12'' N
110° 56' 37'' W42° 55' 12'' N
110° 56' 19'' WN
Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 12N WGS84
0 100 200 400 600
Feet
0 40 80 160 240
Meters
Map Scale: 1:2,730 if printed on A portrait (8.5" x 11") sheet.
Soil Map may not be valid at this scale.
Star Valley Area, Wyoming-Idaho
HuB—Huffine silt loam, 3 to 6 percent slopes
Map Unit Setting
National map unit symbol: 53x1
Elevation: 5,690 to 6,760 feet
Mean annual precipitation: 16 to 24 inches
Mean annual air temperature: 39 to 45 degrees F
Frost-free period: 60 to 90 days
Farmland classification: Farmland of statewide importance, if irrigated
Map Unit Composition
Huffine and similar soils:85 percent
Minor components:15 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Huffine
Setting
Landform:Mountain slopes
Landform position (three-dimensional):Mountainflank
Down-slope shape:Linear
Across-slope shape:Linear
Parent material:Alluvium and/or loess
Typical profile
A - 0 to 11 inches: silt loam
Bt - 11 to 31 inches: silty clay loam
2Ck - 31 to 60 inches: very gravelly loamy sand
Properties and qualities
Slope:3 to 6 percent
Depth to restrictive feature:More than 80 inches
Drainage class:Well drained
Capacity of the most limiting layer to transmit water (Ksat):Moderately high to high
(0.60 to 2.00 in/hr)
Depth to water table:More than 80 inches
Frequency of flooding:None
Frequency of ponding:None
Calcium carbonate, maximum content:5 percent
Maximum salinity:Nonsaline to very slightly saline (0.0 to 2.0 mmhos/cm)
Available water supply, 0 to 60 inches: Moderate (about 7.3 inches)
Interpretive groups
Land capability classification (irrigated): 6c
Land capability classification (nonirrigated): 4s
Hydrologic Soil Group: B
Ecological site: R043BY222WY - Loamy Foothills and Mountains West
Hydric soil rating: No
Minor Components
Thayne l
Percent of map unit:10 percent
Hydric soil rating: No
Custom Soil Resource Report
13
Robana sil
Percent of map unit:5 percent
Hydric soil rating: No
Custom Soil Resource Report
14
Figure B1 – Soil Exploration Pit
Figure B2 – Soil Exploration Pit Excavated Soil
APPENDIX C – WATER QUALITY DATA
ANALYTICAL SUMMARY REPORT
The analyses presented in this report were performed by Energy Laboratories, Inc., 2393 Salt Creek Hwy., Casper, WY 82601,
unless otherwise noted. Any exceptions or problems with the analyses are noted in the report package. Any issues encountered
during sample receipt are documented in the Work Order Receipt Checklist.
The results as reported relate only to the item(s) submitted for testing. This report shall be used or copied only in its entirety. Energy
Laboratories, Inc. is not responsible for the consequences arising from the use of a partial report.
If you have any questions regarding these test results, please contact your Project Manager .
Lab ID Client Sample ID Collect Date Receive Date Matrix Test
Report Approved By:
C22010603-001 Allred Well 01/18/22 10:30 01/19/22 Drinking Water Metals by ICP/ICPMS, Drinking
Water
Mercury, Drinking Water
Fluoride
Anions by Ion Chromatography
Nitrogen, Nitrate + Nitrite
pH
Metals Preparation by EPA 200.2
Digestion, Mercury by CVAA
Gross Alpha Calculated
Gross Alpha, Gross Beta, Total
Solids, Total Dissolved
Sub Sample Documentation
Sunrise Engineering Inc
Project Name:Self Subdivision
Work Order:C22010603
47 East 4th Ave
Afton, WY 83110
February 23, 2022
Energy Laboratories, Inc. Casper WY received the following 1 sample for Sunrise Engineering Inc on 1/19/2022 for analysis.
Page 1 of 17
Digitally signed by
Ashley L. Wilson
Date: 2022.02.23 09:34:26 -07:00
Project:Self Subdivision
CLIENT:Sunrise Engineering Inc
Work Order:C22010603 CASE NARRATIVE
02/23/22Report Date:
Tests associated with analyst identified as ELI-B were subcontracted to Energy Laboratories, 1120 S. 27th St., Billings, MT,
EPA Number MT00005.
Page 2 of 17
LABORATORY ANALYTICAL REPORT
Client:Sunrise Engineering Inc
Project:Self Subdivision
Lab ID:C22010603-001
Client Sample ID:Allred Well
Collection Date:01/18/22 10:30
Matrix:Drinking Water
Report Date:02/23/22
DateReceived:01/19/22
Prepared by Casper, WY Branch
Analyses Result Units Analysis Date / ByRLMethod
MCL/
QCLQualifiers
MAJOR IONS
01/22/22 02:47 / dmb1mg/LNDChloride E300.0
01/21/22 16:36 / kjp0.1mg/LNDFluoride A4500-F C
01/22/22 02:47 / dmb1mg/L4Sulfate E300.0
PHYSICAL PROPERTIES
H 01/20/22 11:58 / mnm0.1s.u.7.9pH A4500-H B
01/20/22 11:58 / mnm°C15.6pH Measurement Temp A4500-H B
01/20/22 13:16 / mnm20mg/L180Solids, Total Dissolved TDS @ 180 C A2540 C
NUTRIENTS
01/20/22 13:20 / nts0.05mg/L0.27Nitrogen, Nitrate+Nitrite as N E353.210
METALS, TOTAL
02/01/22 05:00 / jcg0.001mg/LNDAntimony E200.80.006
02/02/22 06:21 / jcg0.005mg/LNDArsenic E200.80.01
02/02/22 06:21 / jcg0.05mg/LNDBarium E200.82
02/01/22 05:00 / jcg0.001mg/LNDBeryllium E200.80.004
02/01/22 05:00 / jcg0.001mg/LNDCadmium E200.80.005
01/25/22 22:17 / srm1mg/L47Calcium E200.7
02/02/22 06:21 / jcg0.005mg/LNDChromium E200.80.1
02/01/22 05:00 / jcg0.01mg/LNDCopper E200.81.3
D 02/04/22 17:35 / srm0.05mg/L0.34Iron E200.7
02/02/22 06:21 / jcg0.001mg/LNDLead E200.80.015
01/25/22 22:17 / srm1mg/L18Magnesium E200.7
D 02/01/22 05:00 / jcg0.003mg/L0.005Manganese E200.8
01/26/22 13:00 / eli-b0.0001mg/LNDMercury E245.10.002
02/01/22 05:00 / jcg0.01mg/LNDNickel E200.8
D 02/02/22 06:21 / jcg0.002mg/LNDSelenium E200.80.05
02/04/22 17:35 / srm1mg/LNDSodium E200.7
02/17/22 19:13 / jcg0.0005mg/LNDThallium E200.80.002
02/01/22 05:00 / jcg0.01mg/LNDZinc E200.8
RADIONUCLIDES, TOTAL
U 02/03/22 02:33 / hatpCi/L-0.4Gross Alpha E900.0
02/03/22 02:33 / hatpCi/L1.9Gross Alpha precision (±)E900.0
02/03/22 02:33 / hatpCi/L2.0Gross Alpha MDC E900.0
U 02/18/22 15:02 / dmfpCi/L-0.4Gross Alpha - Adjusted E900.015
02/18/22 15:02 / dmfpCi/L1.9Gross Alpha - Adjusted precision (±)E900.0
02/18/22 15:02 / dmfpCi/L2.0Gross Alpha - Adjusted MDC E900.0
Report
Definitions:
RL - Analyte Reporting Limit MCL - Maximum Contaminant Level
QCL - Quality Control Limit ND - Not detected at the Reporting Limit (RL)
D - Reporting Limit (RL) increased due to sample matrix H - Analysis performed past the method holding time
U - Not detected at Minimum Detectable Concentration
(MDC)
Page 3 of 17