January 19, 2021 the City Council Approved a Variance to Section 4.301(D)

COUNCIL MEETING DATE: JANUARY 19, 2021

CITY COUNCIL AGENDA ITEM #8 STAFF PREPARER/CONTACT INFORMATION: Sylvia Carrillo, City Administrator scarrillo@sunsetvalley,org

COUNCIL SPONSOR: Mayor Bruner ([email protected])

SUBJECT: LAND DEVELOPMENT CODE/VARIANCE REQUEST

DESCRIPTION: Consider and act on a requested variance to Section 4.301 (d) of the Land Development Code to allow for increased impervious cover for the business located at 4715 South Lamar. (Mayor Bruner/Administration)

BACKGROUND: 4715 South Lamar (4715) was first developed as Wolfe Nursery in 1993, when impervious cover limits were set at 50%. The current Land Development Code places impervious cover limits at 18%.

The initial development for this property required a variance for placement of the required water quality facilities within the twenty-five-foot vegetative buffer along the right of way, as well as the use of overhead utility lines. On August 3, 1993, the City Council approved the site plan for development of Wolfe Nursery.

To build Wolfe Nursery in 1993, several development right transfers took place. The site is approximately 3.94 acres. However, the site plan indicates that the property has an area encompassing 4.55 acres.

This is due to the transfer of impervious cover from 2 other locations.

The first: In 1993, impervious cover was transferred from what is currently the City-Owned property where the Farmer’s Market is held. This transferred an additional 18,508 square feet of impervious cover to the property of 4715 by removing that amount of allowable impervious cover from the City owned property. The restrictive covenant for that transfer can be found here.

The second: Offsite mitigation for the AISD Parking Lot is also listed as land credited for impervious cover calculations. This was an area within the AISD parking lot that had asphalt removed and trees planted between the site at 4715 South Lamar and the City- Owned property. This provided an additional 8,048 square feet of impervious cover to the site at 4715. Based on these transfers, when the property was first developed in 1993 it was estimated to have approximately 43% impervious cover.

In 2013, when the property went from a single tenant to multiple tenants a full calculation of impervious cover was determined for the site. With the credit from the other properties, the impervious cover is determined to be 47.4%. If the credit from the other properties was removed, impervious cover on this site is estimated at 56.79%.

The applicant has provided a conceptual plan of the project as well as a letter documenting their intentions with the project. The plan includes building a WellMed at the site that would include a medical clinic and senior activity center. The applicant is proposing a significant expansion of the building as well as additional parking.

The proposed impervious cover, with the existing credits and transfers, would be 56.6%. Without the transfers, the estimated impervious cover on the site is approximately 65%.

Because the project exceeds the 50% threshold, several aspects of the project will need to come to current code compliance. This includes the building code in the new portion of the building, landscaping, water quality, and buffering. The applicant is aware of such requirements.

A preliminary review of the project was conducted by the City Engineer and is attached.

This project is in a conceptual phase and provides an opportunity for the City of Sunset Valley to consider how it will approach redevelopment. Although there are challenges, and the project does not meet existing development standards for impervious cover, the City can work with the developer to design a project that is mutually beneficial while also protecting water quality that does meet the intent of water quality protection. This can include new and innovative ways of addressing water quality controls onsite. The applicant has submitted additional methods to address water quality in order to mitigate any increase in impervious cover.

At the January 5, 2021 meeting, the applicant was asked to provide more detailed information for the submittal and for the council to render a decision on the variance request. The applicant has provided the requested information, it is attached here.

APPLICABLE CODE SECTIONS: LDC Chapter 4 – Watershed Development

FUNDING: N/A

STAFF RECOMMENDATION: Approval of the variance request.

Page 2 DOCUMENTS PROVIDED: YES

• 4715 CONCEPTUAL PLAN AND REFINEMENTS REQUESTED • 4715 LETTER • 4715 ENGINEERING REVIEW AND REFINEMENTS REQUESTED

Page 3

January 14, 2021

Peter Navarte VP of Development Central Austin Management Group

Blayne Stansberry, PE Stansberry Engineering

RE: 4715 S Lamar Variance Request for Impervious Cover

Dear Ms. Stansberry and Mr. Navarte:

We have reviewed the resubmitted documents and various correspondence in response to our original comments regarding the variance request for 4715 S Lamar. Some comments may reference the City of Sunset Valley Land Development Code (LDC) and can be found at the Development Department’s webpage at sunsetvalley.org and some comments may reference City of Austin developments codes and those can be found on www.municode.com .

1. Based on the conceptual information/responses provided, and assuming the variance being requested is granted, it appears that the new increase in impervious cover for this proposed site development may be able to meet the non-degradation requirement of development within the Barton Springs Zone. Final design, detailed calculations, and all reports/studies required by the LDC would need to be submitted and confirmed to be compliant with the development codes prior to the final acceptance of the proposed design and mitigation methods.

2. Ms. Stansberry’s response letter to my original comments also acknowledges and reinforces the expectation that the project would need to “meet or exceed all LDC requirements including landscaping, tree mitigation, and building codes” that are outside the scope of this variance request.

If you have any questions about these comments, please feel free to call me at (830) 377-4555.

Sincerely,

Gary Freeland, P.E., CFM Consultant City Engineer for the City of Sunset Valley

Cc: Sylvia Carrillo Carolyn Meredith

Freeland Turk Engineering Group, LLC TBPELS FIRM F-21047 160 Creekside Park Rd, Ste 200, Spring Branch, TX 78070 www.freelandturk.com

January 14, 2021

Mr. Gary Freeland, P.E., CFM City Engineer Freeland Turk Engineering Group, LLC 160 Creekside park Rd., Suite 200 Spring Branch, TX 78070

RE: 4715 S. Lamar Variance Request for Impervious Cover and Vegetated Buffer

Dear Mr. Freeland,

We appreciate your comments on the conceptual plan of the site submitted for this variance request. We offer the following responses.

1. Updated conceptual plans with preliminary water quality volume calculations showing how the new impervious cover will be mitigated are attached.

2. The existing ponds are sized for increased capture of stormwater runoff per the City of Austin regulations for sedimentation / filtration ponds. The total runoff treated by the existing water quality ponds is shown on sheet 4 of 5 as drainage areas 1 and 2 and calculations include the additional impervious cover draining to the existing ponds.

The existing ponds, as originally designed, are oversized and have sufficient capacity to treat the additional impervious. However, since the original construction of the ponds, the City of Austin regulations for pollutant removal over the Barton Springs Zone have increased. Although the existing impervious cover is not required to meet the current regulations, additional treatment will be provided for new impervious cover. For impervious cover draining to the east pond, cisterns and rain gardens are proposed to pretreat approximately 5,000 sq ft of the expanded roof before entering the existing east stormwater pond. This exceeds the 1,620 sq ft of new impervious cover and improves the water quality by removing more pollutants than the existing condition.

3. The additional parking along the east entrance driveway can be treated via pervious pavement infiltration that is directed to a vegetated filter. There is also 2,500 sq ft of existing driveway that is currently untreated. The proposed plan could offset some new impervious cover by treating existing pavement with the proposed stormwater controls.

4. The new dumpster on the west will be located so that runoff drains to the existing west pond. The calculations show the existing west pond has sufficient capacity for the increased impervious cover.

5. The park on the west side will incorporate pervious pavements to extent practical to avoid increased impervious cover.

Texas Registered Engineering Firm F-8276 Post Office Box 309, Manchaca, Texas 78652 512/292-8000 www.stansberryengineering.com Mr. Freeland January 14, 2021 Page 2 of 2

6. Sheets 4 and 5 show the proposed water quality treatments for the areas of new impervious cover. The final design will be in accordance with the City of Austin ECM Barton Springs Zone requirements of non-degradation by removal of 100% of pollutants. This will be accomplished by a main treatment structure sized for the entire drainage area of new impervious cover. The biofiltration pond alone will provide 90% removal. A “treatment train” of various structures such as permeable pavement, rain gardens, and bioswales will pre-filter the runoff before entering the biofiltration pond satisfying the remaining 10% of necessary treatment and providing 100% pollutant removal.

7. A variance to the impervious cover requirement and vegetated buffer is requested. The following items will become part of the Special Use Permit requirements. a. Stormwater runoff from new impervious cover will be mitigated through multiple water quality treatments in accordance with the City of Austin Environmental Criteria Manual as adopted by the City of Sunset Valley. b. Proposed landscape will exceed current code requirements which includes modifying all existing irrigation to a drip system and installing drip in new landscape areas, adding additional landscape on the existing west side parking, and creating a pocket park at the west end of the site.

8. The project will be submitted for site development review and a Special Use Permit pending approval of the variance. The site engineering and review process will ensure the project meets or exceeds all LDC requirements including landscaping, tree mitigation, and building codes.

The goals of this project are to provide 1) water quality treatment that is protective of the groundwater with 100% non-degradation runoff and improves stormwater runoff over the existing runoff and 2) landscaping that exceeds current requirements and enhances the aesthetics of the site and provides a pocket park for the community.

Please let me know if you have any questions regarding this project and the requested variance.

Sincerely,

Stansberry Engineering Co., Inc.

Blayne Stansberry, P.E.

Legend: 1 Proposed Parkland 2 Trellis Shade Structure 3 Butterfly Garden 4 Parking Berm 5 Water Quality Pond 6 Decomposed Granite Walking Path

1 4 2 5 4 3

5 6 4

PREPARED FOR Schematic Masterplan NORTH 4715 South Lamar Blvd. SCALE: 1”=80

Sunset Valley, Texas 0’ 40’ 80’ ISSUE DATE: January 07, 2021 All drawings are preliminary and subject to change. © 2020 Hitchcock Design Group PREPARED FOR Rain Garden & Biofiltration Pond Examples NORTH 4715 South Lamar Blvd. SCALE: 1”=80

LEMON BOTTLEBRUSH TEXAS SAGE YAUPON HOLLY

PREPARED FOR Plant Images - Trees & Evergreen Shurbs NORTH 4715 South Lamar Blvd. SCALE: 1”=80

MEALY BLUE SAGE PINK MUHLY GRASS TEXAS SEDGE

PREPARED FOR Plant Images - Short Herbacious Plants NORTH 4715 South Lamar Blvd. SCALE: 1”=80

COPPER CANYON DAISY INDIAN GRASS OBEDIENT PLANT

PURPLE POPPY MALLOW SWITCHGRASS WOOD OATS

PREPARED FOR PlantDrawing Images Title - MediumHerbacious Plants NORTH 4715 South Lamar Blvd. SCALE: 1”=XX’

Sunset Valley, Texas 0’ XX’ XX’ XX’ ISSUE DATE: January 07, 2021 All drawings are preliminary and subject to change. © 2020 Hitchcock Design Group (TEXAS STATE HIGHWAY 71) (A.K.A. LAMAR BOULEVARD SOUTH) (R.O.W. VARIES)

EXISTING STORMWATER PONDS

CONCRETE

12,613 SF EXISTING 1-STORY BUILDING 98 SPACES (EAST) EXISTING CONCRETE ASPHALT CONCRETE COMPACT PARKING VEGETATED 87 SPACES (WEST) FILTER

GUI

EXISTING SITE PLAN

WELLMED MEDICAL GROUP 4715 S LAMAR BLVD EXISTING SITE PLAN 14 JANUARY 2020 Texas Registered Engineering Firm F-8276 phone 512 / 292-8000 www.stansberryengineering.com Sheet 1 of 5 (TEXAS STATE HIGHWAY 71) (A.K.A. LAMAR BOULEVARD SOUTH) (R.O.W. VARIES)

EXISTING STORMWATER PONDS

12,613 SF 19,450 SF EXISTING 1-STORY 1-STORY BUILDING BUILDING EXPANSION BIO- COMPACT PARKING 100 SPACES (EAST) FILTRATION 87 SPACES (WEST) POND

GUI

CONCEPTUAL SITE PLAN

NOTES 1. AN EROSION CONTROL PLAN IN COMPLIANCE WITH TPDES WILL BE IMPLEMENTED FOR THE LIMITS OF CONSTRUCTION.

WELLMED MEDICAL GROUP 4715 S LAMAR BLVD CONCEPTUAL SITE PLAN 14 JANUARY 2020 Texas Registered Engineering Firm F-8276 phone 512 / 292-8000 www.stansberryengineering.com Sheet 2 of 5 0 80' (TEXAS STATE HIGHWAY 71) (A.K.A. LAMAR BOULEVARD SOUTH) (R.O.W. VARIES)

EXISTING STORMWATER PONDS

STORMWATER STORMWATER RUNOFF RUNOFF

WEST POND EAST POND 0.76 AC DRAINAGE AREA 12,613 SF 1.24 AC DRAINAGE AREA (PER CANNOLI JOE'S SITE PLAN) EXISTING 1-STORY BUILDING

EXISTING 0.17 AC AREA VEGETATED DRAINING TO EXISTING FILTER VEGETATED FILTER (PER CANNOLI JOE'S SITE PLAN)

EXISTING DRAINAGE MAP

WELLMED MEDICAL GROUP 4715 S LAMAR BLVD EXISTING DRAINAGE PLAN 14 JANUARY 2020 Texas Registered Engineering Firm F-8276 phone 512 / 292-8000 www.stansberryengineering.com Sheet 3 of 5 0 80' (TEXAS STATE HIGHWAY 71) (A.K.A. LAMAR BOULEVARD SOUTH) NEW IMPERVIOUS RG 1 (R.O.W. VARIES) COVER 250 CF RAIN GARDEN TREATS ±1,000 SF ROOF AREA

NEW PARKING EXISTING STORMWATER PONDS (IMPERVIOUS COVER) WEST POND EAST POND 4 810 SF DRAINAGE AREA STORMWATER RUNOFF STORMWATER RUNOFF

NEW IMPERVIOUS 2 RG1 COVER VEGETATED WEST POND EAST POND CISTERNS RG4 0.76 AC DRAINAGE AREA 12,613 SF 1.17 AC DRAINAGE AREA 3 FILTER 320 SF ADDITIONAL IMP COVER EXISTING (NET DECREASE 0.07 AC) 0.63 AC DRAINAGE AREA 1-STORY BUILDING 1,620 SF ADDITIONAL IMP COVER RG5 BIO 1 0.17 AC AREA FILTRA- DRAINING TO EXTG TION VEGETATED FILTER NEW DRAINAGE DIVIDE POND

RG2 BIOSWALE

RAINWATER HARVESTING 1,500 GAL CISTERNS TREATS ±2,000 SF ROOF AREA RG 2 2,500 SF EXISTING UNTREATED NEW PARKING 250 CF RAIN GARDEN AREA TO RECEIVE WATER QUALITY (IMPERVIOUS COVER) TREATS ±2,000 SF ROOF AREA TREATMENT

PROPOSED DRAINAGE MAP & WATER QUALITY PLAN

* PER CANNOLI JOE'S SITE PLAN

WELLMED MEDICAL GROUP 4715 S LAMAR BLVD PROPOSED DRAINAGE MAP & WATER QUALITY PLAN 14 JANUARY 2020 Texas Registered Engineering Firm F-8276 phone 512 / 292-8000 www.stansberryengineering.com Sheet 4 of 5 PERVIOUS CONCRETE IN EXTG EAST STORMWATER POND PARKING AREAS WITH DRNG AREA 4 UNDERDRAIN PIPING TO 810 SF BIOFILTRATION POND PERVIOUS CONCRETE IN PARKING AREAS WITH UNDERDRAIN PIPING TO DISCHARGE AT VEGETATED FILTER

0 40'

DRNG AREA 3.1 0.19 AC TO RG 3, 4, 5 & BIOFILTRATION

RG4 VEGETATED FILTER 3,800 SF

RG3 RG5

DRNG AREA 3.2 DRNG AREA 3.3 BIOFILTRATION NEW DRAINAGE DIVIDE RG 3 0.24 AC 0.20 AC POND 150 CF RAIN GARDEN TO PERVIOUS PAVEMENT TO PERVIOUS PAVEMENT & 3,100 CF TREATS ±2,000 SF & BIOSWALE BIOFILTRATION

BIOSWALE

324 LF BIOSWALE PERVIOUS CONCRETE IN PARKING LOT DETENTION 2' BOTTOM WIDTH, 1% SLOPE PARKING AREAS WITH (SHADED) MINIMUM LENGTH 78 FT UNDERDRAIN PIPING TO 3,000 CF BIOFILTRATION POND WATER QUALITY/DETENTION PLAN

NOTES

1. WATER QUALITY TREATMENT FOR NEW IMPERVIOUS COVER WILL COMPLY WITH THE CITY OF AUSTIN ENVIRONMENTAL CRITERIA MANUAL OF 100% NON-DEGRADATION WITHIN THE BARTON SPRINGS ZONE OF THE EDWARDS AQUIFER.

2. THE VARIOUS WATER QUALITY MEASURES PRESENTED FOR THE PLAN ARE PRELIMINARY AND SUBJECT TO CHANGE DURING THE SITE DEVELOPMENT REVIEW & PERMITTING.

WELLMED MEDICAL GROUP 4715 S LAMAR BLVD WATER QUALITY / DETENTION PLAN 14 JANUARY 2020 Texas Registered Engineering Firm F-8276 phone 512 / 292-8000 www.stansberryengineering.com Sheet 5 of 5