How to avoid unintended consequences in Brownfield redevelopment and LEED certification.

As Leadership in Energy & Environmental Design (LEED^®) gains velocity, unintended consequences are occurring increasingly with programs involving Brownfield sites and green design. Brownfields are real property, of which the expansion, redevelopment, or reuse may be complicated by the presence, or potential presence, of environmental contamination. Although re-using such property is an automatic one point toward obtaining LEED project certification, Brownfield projects can suffer by inadvertently limiting future “green” building and sustainable design with traditional application of land use controls (LUCs). The result is a collision of good intentions.

LUCs are a reasonable and cost-effective part of the cleanup process. Brownfield LUCs do not clean up contamination, but can responsibly manage the chemical risk of contaminants left in-place. LUCs can be engineered structures such as impervious parking lots used as caps or institutional controls such as deed restrictions prohibiting excavation.

While Brownfield LUCs defer costs of a physical cleanup to preserve available capital for initial reconstruction, they may directly oppose vital construction concepts of green architecture. For instance, the use of pavements as caps over contamination to ‘shed’ water from the property contradict “green” use of permeable pavements to maximize on-site stormwater retention. Parking lots can conflict with green space, water features, and ecological habitat restoration.

However, such collisions are avoidable. If we understand how and when Brownfield redevelopment affects LEED, we can progress from what have been sequential, or at best parallel, pathways to a process that integrates Brownfield and LEED early in site-planning. Sustainable design can be incorporated earlier in the project by making it part of the environmental assessment and early cleanup planning.

An understanding of the relationship between Brownfields cleanup and green design in LEED-certified redevelopment also provides opportunities for valuable LEED credits using Brownfield assessment information to support green building requirements related to sustainable site planning and water resources.

Traditional brownfields reuse
Consider the following scenario. You are the developer of a contaminated Brownfield property, which in some areas exceeds cleanup levels. Your environmental consultant offers you two options for closure.

Option 1: “Clean” restoration with unrestricted land use; cost approximately $500,000:

• • Treat or remove and dispose of contamination and backfill with clean soil.
• • Some nominal low-level residual contaminants may remain in isolated areas.
• • Stormwater may or may not be diverted off-site.

Option 2: Risk-based restoration with restricted land use; cost approximately $80,000:

• • Construct using the proposed parking lot and building as an impervious cap for risk-based closure; contaminants remain beneath the structures and the cap.
• • Divert 100% of rainwater off-site through storm sewers to nearby stream.
• • Land use controls restrict soil excavation or construction below a depth of 3 feet.

As mentioned earlier, the application of LUCs in lieu of remediation for Brownfield sites is well advanced and accepted by regulatory agencies.  As a developer seeking to preserve reconstruction capital, your choice appears obvious. Option 2 is a reasonable, fiscally responsible, environmental-management process to bring an abandoned and contaminated property back to productive reuse for the community.

Sustainable Brownfield redevelopment rarely occurs in a single restoration. Traditionally the first-build position is the initial restoration and makes maximum use of LUCs, tailoring them to fit the physical reconstruction at lowest cost.

The second build may expand the initial reconstruction or occur as peripheral redevelopment, usually within a few years following the first. Although LUCs do not fit the second build exactly, design- and construction-cost adjustments to accommodate them are not significant enough to be ‘deal killers’.

The third-building position occurs much later in the restoration timeline and may involve fundamentally different concepts in planning and design unlike those of previous build positions. Today we find ourselves in this situation, transitioning from traditional brick-and-mortar construction to sustainable and energy efficient LEED reconstruction.

Brownfields and green building seem synonymous with sustainable development. The property above is cleaned up using Option 2 and seeks a developer. The impervious parking lot prevents contact with subsurface chemicals in soil. The public health and environment are protected.

Suppose then, a developer’s architect proposes a project for the site. The architect’s goal is to achieve a LEED-gold rating for commercial reconstruction. With only seven points separating basic certification and a Gold rating, the property attracts the architect because it provides one point by addressing Development Density & Community Connectivity. The property provides another point for Brownfield development. The design may score additional points through sustainable site planning and safeguarding water resources in the following LEED categories:

• 1 Point     Site Development - Protect or Restore Habitat , SS5.1
• 1 Point    Stormwater Design - Quantity Control, SS6.1
• 1 Point    Stormwater Design – Quality Control, SS6.2    
• 1 Point    Water Efficient Landscaping, WE1.1
• 1 Point    Water Efficient Landscaping,
• Additional Credit, WE1.2

The green design achieves points by reducing stormwater quantity leaving the site and improving quality by filtering stormwater through on-site soils before it reaches groundwater. This will be done using permeable pavements, bioswales and excavated water features. The water features and surrounding re-vegetation with native plants will also provide habitat protection and restoration. Water-efficient landscaping, such as rain gardens using harvested rainwater stored underground, will contribute points.

The architect’s Brownfield restoration design followed “green’” reconstruction, it has all come together nicely … in a train wreck.

Unbeknownst to the architect, the Brownfield LUCs prohibit (by law) essential elements of the green design. Impermeable pavement separates contaminants from public exposure and rainwater from the subsurface. The institutional restriction on excavation below three feet in depth severely limits water features and halts underground storage of harvested rainwater. Permeable pavements would void the LUC, allowing stormwater to pass through buried contaminants and degrade groundwater quality. The simplistic answers for the developer are to run screaming from the property or return to Option 1 to spend the $500,000 to clean the property up to unrestricted use and remove the LUCs. Both would be a “deal killer” for the project.

How did we arrive here to stand among a wreckage of good intentions?

“Green” brownfields reuse
When collisions occur, it results from a traditional misconception that “green” building on Brownfield properties is a sequential and linear process.

The reality is “an ounce of prevention is worth a pound of cure” or, in our scenario, about a half a million dollars. Let’s rewind our theoretical project above.

Collision is avoidable. Consider a less traditional approach in which Brownfield cleanup and green building are not sequential, but simultaneous. An approach where green design will enter much earlier in the property restoration process than is the norm and merges gently with the Brownfield process.

Design of LUCs can consider LEED criteria. Cleanup can consider effects on construction and physical infrastructure necessary for certification. For example, you excavate a hole for cleanup. Fill the hole with water and it becomes waterfowl habitat or a stormwater reservoir.

Sustainable redevelopment concepts at the assessment stage
Brownfields projects can prepare for LEED and ‘green’ design even before the two technical disciplines merge for an actual project.  Environmental assessment data can be used to map a property beyond the chemistry, identifying areas that appear to best support sustainable re-construction features. The result is a Brownfield site positioned for both “green” developers, Smart Growth-related cleanup and elevated scoring in a future LEED project.

Assessment mapping considers parameters for certification of a LEED Neighborhood Development (Pilot), specifically how site soil and contaminant conditions may affect or support Green Construction & Technology, Credit 8: Contaminant Reduction in Brownfields Remediation and Credit 9: Stormwater Management. This provides architects/designers with three-dimensional mapping of residual contaminants for optimal placement of rain gardens or permeable pavements in areas which will not promote secondary mobility of subsurface residual contaminants to groundwater.

In areas where cost or avoidance of elevated residual contamination might have to occur during cleanup and reconstruction, assessment sustainability mapping can assist designers in identifying areas where green design can be used as part of the remedy. This might occur by designing impermeable, rainwater-harvesting structures that act as subsurface “caps” for deeper contaminated materials but allow near-surface water movement and infiltration for collection. This allows constructing a parking lot of permeable pavement that allows stormwater infiltration and reduces surface water contamination.

Essential in Brownfield development and LEED convergence is integrating the planning and design phases early so that land use controls for cost-effective cleanup or contaminant management become part of green design. Avoid the collision. It’s time to re-examine the current linear pathways of thinking—your Brownfield development’s long-term success and profitability in the new “green society” may depend on it. SLDT