Not your "typical" landscape project!
By Kristin Trojanowski, Flaska Landscaping
A. Project Overview
The primary objective of this landscape project was to raise the grade by 8 feet on nearly the entire site. The objective was to develop a viable parking lot for the hotel, with water storage holding tanks beneath the parking lot.
The proposed retaining walls support the significant grade change, serve as a functional, aesthetically pleasing, and sustainable solution to the design and engineering of this project.
The landscape portion of the project needed to adhere to the Township restrictions & requirements, as determined after a long permitting process.
B. The Design Process/Planning
Engineering water storage: All site water was required to remain onsite and stored under the parking lot. Due to the high-water table, all water storage needed to be contained 8-feet above existing grade. This resulted in the required retaining walls to change the site elevation.
Engineering retaining walls: We worked closely with the wall engineers to develop a plan to construct the wall with zero bater and still maintain structural integrity for heavy traffic and dynamic loading. Much of the design planning and engineering solutions occurred while we were under construction. This project presented many issues the manufacturer had never encountered previously.
C. Construction Challenges and Solutions
Time Crunch: The owner had a tight timeline and wanted to open the hotel to customers within the summer season. Although this was a huge undertaking, we commited ourselves to the goal & understood their needs. We worked closely with the owner, the excavator & other contractors on site to coordinate schedules and the various phases of infrastructure which needed to be carefully sequenced for this project.
Logistics: The hotel is located on a narrow site, along a busy State highway, through the downtown waterfront corridor. This presented both opportunities and challenges. Staging equipment and materials was limited, and parking was minimal. The building construction occurred concurrently with the installation of the retaining walls & landscape. With the elevated side property lines, due to the 8' high retaining walls, the project site had only a single entry & exit point for all construction traffic. There was limited room on site for materials. Therefore, a second drop location and staging area had to be setup and utilized down the road.
Drainage: Part of the permitting requirements was for all of the water run-off storage from the site to be stored on- site and UNDER the parking lot.
Materials (hard & soft): Wall: The retaining wall needed to be 8' high, vertical, and have the natural stone appearance the owner desired. High Format Grand Ledge wall material was selected, but every block needed to be modified by hand in order to eliminate any wall batter. Due to this, every course of wall required 10-feet of geogrid and 8-feet of aggregate backfill to meet engineering requirements. There were 260 pallets of retaining wall block installed. This necessitated 1,500 CY of crushed aggregate, 12 rolls of geogrid & roughly 5,000 CY of fill material. Setbacks: The wall was to be built as close to the property line as possible. An existing stockade fence was in place right on the property line and was to remain in place. This posed quite a challenge for wall constructed, but we were able to work within this constraint. Signage: The 6” version High Format Kodah wall block was selected for the entry sign planter area. This matches exactly with the Grand Ledge wall material. However, the owner wanted the freestanding portion of the wall taller than the manufacturers recommendation; with the objective to hide cars from the roadside view. To solve this height issue, we cored blocks, installed over 200 sticks of # 4 rebar, and applied epoxy to each core in the freestanding wall. This created a physical connection and reinforcement from block to block. Plantings: The plant material needed to meet the Township requirements, yet with the required number of parking spaces and the size of the building, there was very minimal planting bed areas left for perennials – let alone trees! We fit plant material in wherever we could. To assure survival, the planting medium used was very nutrient rich and all vegetation was irrigated via an environmentally conscious drip irrigation system.
Parking Barriers: The day of the hotel inspection, a potential new hotel hire drove into the brand-new building. The hotel quickly realized they need parking bumpers right away. It only made sense for us to install Kodah wall blocks to match the other hardscape elements. We installed these by core drilling and using rebar & epoxy to connect to pavement; much like the signage wall.
D. Project Results
The hotel opened on time, as scheduled. The project came together beautifully and was well received by the Township and the Community. The plant material will continue to develop and soften all the hard surfaces. We look forward to watching this project mature.
