GPGT-22-070_Pre_Geo_Proposed_SRA_and_Swale_Areas_Umatilla_Industrial_Park_Lake_Co_Florida.pdf

June 14, 2022

GPGT-22-070

To: Halff Associates, Inc.

902 North Sinclair Avenue Tavares, Florida 32778

Attention: Mr. Duane Booth, P.E.

Subject: Preliminary Geotechnical Investigation, Stormwater Retention Pond and Swale Areas, Proposed Umatilla Industrial Park, Umatilla, Lake County, Florida

Dear Mr. Booth:

As requested, Andreyev Engineering, Inc. (AEI) has completed a preliminary geotechnical investigation for the above referenced project. We understand the subject site improvements include plans for proposed stormwater retention and swale areas. The following report presents the results of our preliminary geotechnical investigation along with an evaluation of the soil and groundwater conditions encountered.

SITE LOCATION AND PROJECT DESCRIPTION

The site is located along Lake Ferns Road, within Section 14, Township 18 South and Range 26 East, in Umatilla, Lake County, Florida. We have included the U.S.G.S. Topographic Map, which depicts the location of the site, on the attached Figure 1. In addition, the Natural Resources Conservation Service (NRCS) Soil Map, which depicts the location and general soil types of the subject site and is presented on the attached Figure 2.

PURPOSE AND SCOPE OF SERVICES

The purpose of this study was to explore the subsurface soil and groundwater conditions at this site to provide recommendations for stormwater retention system design.

The scope of this investigation included:

Drilled five (5) machine auger borings, designated as AB-1 through AB-5, to depths of 15 to 25 feet below ground surface, within the proposed stormwater retention pond and swale areas.

Collected four (4) undisturbed permeability tube samples from the stormwater retention pond and swale areas and conducted permeability testing on the tube samples.

Samples were recovered from the borings and returned to AEI’s laboratory for visual classification and stratification. Soils strata were classified according to the Unified Soil Classification System

Preliminary Geotechnical Investigation, Proposed Umatilla Industrial Park City of Umatilla, Lake County, Florida

(USCS). The approximate boring locations are shown on Figure 3 and results of the auger borings, in profile form, are presented on Figure 4. On the profile, horizontal lines designating the interface between differing materials represent approximate boundaries. The actual transition between layers is typically gradual.

NATURAL RESOURCES CONSERVATION SERVICE SOIL SURVEY

The publication titled “Soil Survey of Lake County, Florida” published by the U.S. Department of Agriculture, Natural Resources Conservation Service (NRCS) was reviewed. For your reference, we have included a portion of the NRCS Soil Map which depicts the location of the subject site on the attached Figure 2. The four (4) soil map units for the subject project location are identified as:

*Soil Map Unit 1: Sparr Sand, 0 to 5 Percent Slopes

Brief Description: “This soil is nearly level to gently sloping and is somewhat poorly drained. It is on broad, low ridges and knolls. The slopes are convex. Typically, the surface layer is gray fine sand about 8 inches thick. The subsurface layer, to a depth of about 57 inches, is pale brown and very pale brown fine sand. The substratum layer, to a depth of about 80 inches, is mottled light gray sandy clay loam. The water table is at a depth of 18 to 42 inches. This soil has low water capacity and permeability is considered to be moderately high to high.”

Soil Map Unit 20: Immokalee Sand

Brief Description: “This soil is a nearly level, poorly drained soil that has a layer at a depth of 30 inches or more that is stained by organic matter. The water table is normally at a depth of 10 to 40 inches. It is within a depth of 10 inches for 1 to 2 months during rainy seasons and falls below 40 inches during prolonged drought. Immokalee sand is moderately permeable in the weakly cemented layer, at depths between 38 and 56 inches, and is rapidly permeable in the other layers. The weakly cemented layer, at depths between 38 and 56 inches, and is rapidly permeable in the other layers. The weakly cemented layers have medium available water capacity, moderately high organic matter content, and low natural fertility. The sandy surface and subsurface layers and the layer between depths of 56 to 68 inches have very low available water capacity and very low natural fertility.”

Soil Map Unit 42: Pompano Sand

Brief Description: “This is a nearly level, poorly drained soil. In a representative profile the surface layer is black sand about 5 inches thick. Below this is a layer of dark grayish brown sand about 4 inches thick. The next 52 inches is gray and white sand that overlies 19 inches of pale brown sand mottled with dark grayish brown, grayish brown, and light brownish gray. The water table is at a depth of 10 inches for 2 to 6 months of the year and at a depth of 10 to 40 inches during the rest of the year. The lowest areas are covered with shallow water after heavy rain. Pompano Sand, has very low available water capacity and low organic matter content. Permeability is high to very high. This soil has severe limitations for use as foundations for low buildings, septic tank filter fields, roads and paved parking areas, playgrounds, paths and trailers, basements and below-ground fallout shelters, and cemeteries due to high water tables.”

Soil Map Unit 49: Wauchula Sand

Brief Description: “This is a nearly level, poorly drained soil that has a loamy subsoil below a layer stained with organic matter. It has a black sand surface layer about 6 inches thick and a light brownish-gray sand subsurface layer about 16 inches thick. Below this is a layer of black sand, about 6 inches thick, that is weakly cemented with organic matter.

The next layer is about 4 inches of weakly cemented dark reddish-brown sand. A layer of dark-brown sand that has weakly cemented fragments of dark reddish-brown sand is present between depths of 32 and 35 inches. Below this is a layer of very pale brown sand, about 3 inches thick, mottled with brown and strong brown. The next layer, to a depth of 44 inches, is very pale brown sandy loam. Below this, and extending to a depth of 80 inches, is mottled sandy clay loam. The water table is within a depth of 10 inches for about 2 months each year. It fluctuates between depth of 10 to 40 inches the rest of the year, except during extended dry periods, when it is below 40 inches. formed in sandy and loamy marine sediments. In most years, under natural conditions, the water table is at a depth of 10 to 40 inches for more than six months. Wauchula sand is rapidly permeable to a depth of about 22 inches and moderately permeable below this to a depth of 80 inches. Available water capacity is very low to a depth of 22 inches and medium below this to a depth of 80 inches. This soil has severe limitations for use as foundations for low buildings, septic tank filter fields, playgrounds, paths and trailers, basements and below-ground fallout shelters, and cemeteries due to high water tables. This soil has moderate limitations for use as roads and paved parking areas and golf courses due to high water tables.”

* This soil map unit is not present in the 1975 NRCS Soil Survey publication for Lake County, including revisions made to soil descriptions in 2004, and has been interpreted from an adjacent or nearby county’s NRCS Soil Survey publication.

SOIL AND GROUNDWATER CONDITIONS

Soil Conditions

The soil types encountered at the boring locations are presented in the form of soil profiles on the attached Figure 4. The stratification presented is based on visual examination of the recovered soil samples and the interpretation of the field logs by a geotechnical engineer.

In general, the borings encountered the following soil Strata:

Dark brown to grayish brown to gray slightly silty fine sand (Stratum 1)

Orangish brown to light grayish brown to light gray slightly silty fine sand (Stratum 2)

Gray to orangish brown to yellowish brown clayey fine sand (Stratum 3)

Dark brown to brown to gray to light gray silty fine sand (Stratum 4)

Laboratory Testing

Nine (9) samples selected from boring locations AB-1 thru AB-5 were tested for moisture content and percent fines passing a U.S. 200 Sieve. The results of the laboratory testing are presented on Figure 4, adjacent to the tested depths.

Groundwater Conditions

At the time of drilling, groundwater was encountered at 9.3, 9.2, 8.3, 5.1 and 5.4 feet below the existing ground surface elevation at borings AB-1 thru AB-5, respectively. Based on the encountered subsurface conditions, our local experience, NRCS soil survey, and antecedent rainfall conditions, it is our opinion that the normal seasonal high groundwater level is estimated to exist 2 feet above measured levels or in a temporary perched condition about 0.5 foot above the encountered Stratum 3 clayey soils, during periods of heavy or extended rainfall.

EVALUATIONS AND RECOMMENDATIONS

Stormwater Retention Pond and Swale Areas

Based on the results of the stormwater retention pond and swale area borings, the soil conditions located in the vicinity of AB-1 through AB-5, appear suitable for shallow dry stormwater retention system design. On-site Strata 1 and 2 slightly silty fine sands excavated from the retention pond and swale areas should be suitable for general fill purposes.

For analysis and design purposes the following aquifer characteristics should be used. These aquifer characteristics were determined from the results of the field and laboratory investigations, adjusting for depth and soil variability:

Boring Location

Bottom of

Aquifer (ft bls)*

Avg. Unsat.

Vertical

Hydraulic Conductivity

(ft/day)

Avg.

Horizontal Hydraulic

Conductivity (ft/day)

Seasonal High

Groundwater Level (ft bls)*

Soil Storage Coefficient

AB-1 12.0 16.1 37.0 7.3 0.25

AB-2 10.0 16.1 36.9 7.1 0.25

AB-3 9.0 16.1 37.0 6.2 0.25

AB-4 5.5 16.3 29.0 3.1 0.20

AB-5 6.0 16.1 37.0 3.4 0.20

*- feet below land surface

Factors of safety have not been applied to the above weighted average permeability values. For the purpose of recovery analysis in accordance with water management district rules, a factor of safety of 2 should be applied to the unsaturated vertical permeability to account for long-term performance and siltation of the pond bottom.

The following formulas were used in the calculation of both the weighted average horizontal and weighted average vertical permeabilities:

Weighted Average Vertical Permeability =

Weighted Average Horizontal Permeability =

LIMITATIONS

This report has been prepared for the exclusive use of Halff Associates, Inc., and their designers, based on our understanding of the project as stated in this report. Any modifications in design concepts from the description stated in this report should be made known to AEI for possible modification of recommendations presented in this report. The geotechnical exploration and recommendations submitted herein are based on the data obtained from the soil borings presented on Figure 4. No other warranty, expressed or implied, is made as to the professional advice presented herein. The report does not reflect any variations which may occur adjacent to, between, or away from the borings. The nature and extent of the variations between the borings may not become evident until during construction. If variations then appear evident, it will be necessary to re-evaluate the recommendations presented in this report. An on-site visit may be required by a geotechnical engineer to note the characteristics of the variations during the construction period. This preliminary geotechnical study provides a general evaluation of the site, drilled to depths of 15 to 25 feet below ground surface, and was not intended to investigate deeper soil conditions with regards to the presence or absence of Karst activity.

CLOSURE

AEI appreciates the opportunity to participate in this project, and we trust that the information herein is sufficient for your immediate needs. If you have any questions or comments concerning the contents of this report, please do not hesitate to contact the undersigned.

Sincerely, ANDREYEV ENGINEERING, INC.

Mark Livingston Raymond W. Jones, P.E.

Project Manager Vice President

Florida Registration No.58079 n n

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FIGURES

PROJECT

AREA

Andreyev Engineering, Inc.

GRAPHIC SCALE: 1"=2000'

2000 40001000

UMATILLA INDUSTRIAL PARK

PROJECT

AREA

XX

Andreyev Engineering, Inc.

GRAPHIC SCALE: 1"=300'

300 600150

AB-1

AB-2

AB-3

AB-4 AB-5

Andreyev Engineering, Inc.

GRAPHIC SCALE: 1"=200'

200 400100

Andreyev Engineering, Inc.