Indianapolis International Airport’s new main passenger terminal building reflects the Indianapolis Airport Authority’s (IAA) commitment to sustainable design in many ways — some quite visible and others literally below the surface. The new 1.2-million-square-foot terminal, with its distinctive arched roof, is designed to conserve energy and resources through daylighting, solar shading and natural air-cooling. The terminal’s midfield location – between the two existing main runways – will also reduce fuel consumption, aircraft noise, and air pollution. Below the surface of the terminal apron, a custom-designed dual-collection system for the separation of high- and low-concentrated flows of propylene glycol-based aircraft deicing solution and a water-quality treatment and deicing runoff control facility will protect Indiana’s streams and increase the opportunity to recycle used solution. The airport project is registered under the U.S. Green Building Council’s (USGBC) Leadership in Energy and Environmental Design (LEED)TM program.


A “Greenfield” Location
Indianapolis International Airport opened in 1931. Occupying approximately 7,700 acres, the existing airport comprises a 673,000-square foot terminal with 33 gates, and garage and surface parking facilities for almost 11,000 vehicles. It is served by approximately 10 major and 19 national/regional passenger airlines. The new airport is located on a “greenfield” site that has been reserved for the airport’s expansion since 1975. The site is nearly a mile wide and over two miles in length, with ample space for landside and airside development. It comprises the passenger terminal with two concourses, 40 passenger gates, 90,000 square feet of retail space, 55,000 square feet of office space, and state-of-the-art security, passenger conveyance and baggage handling facilities; a new Federal Aviation Administration (FAA) air traffic control tower; and a new main entrance from Interstate 70 through a dedicated interchange. Because of its strategic location, aircraft taxiing distance will be reduced, along with fuel consumption, noise and pollution.

As master-planned by architects Hellmuth, Obata + Kassbaum, Inc. (St. Louis, MO/Indianapolis, IN) and designed by Aero Design Group (Indianapolis, IN) the terminal building maximizes daylighting and natural cooling, while reducing solar heat gain. The arched roof is key to achieving these sustainable design goals: it will shade glass walls from the sun, collect natural light through skylights, optimize airflow for natural cooling, reflect heat, and channel rainwater for collection.  


A Critical Component
The separation of stormwater on the apron is a critical component of the new aircraft terminal apron. Woolpert designed the airside storm sewer mains that will handle all of the stormwater from the 110-acre terminal apron area. Thus a dual-collection system was designed to separate both high and low concentrated flows of propylene glycol-based aircraft deicers that will be used for deicing in the new terminal apron area. High concentrations of glycol run-off will occur specifically in the areas surrounding the aircraft parking positions, while lower concentrations of glycol run-off will occur in other areas including taxi-lanes, open apron areas and grass areas surrounding the apron. The segregation of high concentrate runoff increases the opportunity for the recycling of aircraft deicers, and is consistent with IAA’s commitment to sustainable design.

Woolpert conducted drainage studies to address those drainage areas that would capture both high- and low-concentrated amounts of runoff. The recommended design solution — based on conduit size, construction costs and constructability — is a dual box culvert system approximately 3,000 feet in length running south to north beneath the new apron. The dual system was built side-by-side with a 1 foot separation, which allows for proper granular backfill placement during construction. The dual box culverts were constructed on a 6-inch aggregate base at approximately 20 feet in depth. The box culvert sizes vary in size from 4’x4’ to 7’x6’. Each box section is further being wrapped with a 12’-wide mastic joint wrap with metal bands to minimize ground water infiltration and to protect from exfiltration of glycol liquids.

The apron inlet and storm sewer systems were also separated to capture the high and low concentrations of glycol and stormwater run-off. These lateral systems then connect to either the high concentration box culvert or to the low concentration box culvert.

The cost of this stormwater box culvert separation system was approximately $3.5 million. It was constructed in 150 days, which was within the project schedule. Construction management was provided by Turner-Trotter (Indianapolis), and general contracting by Gradex, Inc. (Indianapolis). This system was completed in 2005.


Water Treatment and Run-off Control
The stormwater box culvert separation system feeds the water quality treatment and deicing runoff control facility. Water quality treatment — removal of suspended solids — is performed via two Vortechs Systems, one for each drainage system. The units were sized by M.D. Wessler & Associates (Indianapolis) based upon the City of Indianapolis’ requirement to remove 80 percent of the total suspended solids generated by a 0.3” storm event (using an Ok-110 particle size distribution). The low-concentrate system treats up to 53 cubic feet per second (cfs) and the high-concentrate systems treats up to 58 cfs.

After receiving water quality treatment, the terminal apron runoff will arrive at the influent diversion structure, which consists of a series of six sluice gates, up to 9’x7’ in size, which divert runoff to one of three destinations: high-concentrate storage, low-concentrate storage, and the receiving drainage system. Two biochemical oxygen demand meters will monitor the glycol concentration in the high- and low-concentrate influent streams. Based upon these readings, the influent will be routed to the appropriate destination via opening and closing of the sluice gates.

The underground storage vault, which is nearly 300 feet in length, is partitioned into four 24’x10’ cells. Runoff is temporarily stored in the underground storage vault and routed through an effluent diversion structure to a lift station. The effluent diversion structure allows for independent routing of high concentrate and low concentrate runoff to the lift station via two sluice gates. The lift station has a capacity of 12,400 gallons per minute and discharges through a 30” force main to a larger equalization facility located in the airfield.

The underground storage system is designed to allow for up to 1.9 million gallons of runoff to be stored in the ramp drainage system during periods of heavy precipitation. Overflow weirs in the influent diversion structure allow for overflows to the receiving drainage system to occur prior to causing any flooding problems at the ramp. The storage requirements were based upon a model that analyzes 30 years of hourly precipitation data. The goal was to maximize NPDES permit compliance while balancing project costs.

The water quality treatment and deicing runoff control facility will be monitored and controlled remotely via a supervisory control and data acquisition system. Now under construction, the estimated construction cost of the facility is $18 million.


Most Modern in U.S.
The underground storage system, water quality treatment system, and pump station will be among the most modern at any airport in the United States. These systems will have applicability in other situations, as well. For example, this type of water-quality treatment system can be used for stormwater treatment for commercial development, as well as for combined sewer overflow treatment, and pump stations are typically used for wastewater conveyance on sanitary sewer systems. The underground storage tank performs a function similar to storage for combined sewer systems, temporarily storing combined sewage during wet weather to prevent overflow into receiving streams.

Construction of the new terminal building began in July 2005, and it is scheduled to open in late 2008. The total $1.1 billion cost of the new airport is being financed through a combination of federal grants, passenger facility charges, airline facility rents and aircraft landing fees. LDT