After a recent roundtable discussion with a group of architect clients we mostly concluded that the urban market has returned first and will remain strong through continued development in our city centers.

During the 1990s the Baby Boomers were in their family forming years and the nations suburbs grew faster than its cities. Jobs and retail followed housing and infill urban development had many perceived challenges.

Moving forward from 2010 however demographic trends and perceived barriers such as traffic and quality of life will likely drive demand for more urban products.

As Boomers retire many are choosing different lifestyles, trading in the 5 bedroom house and yard for well located townhomes, condos and senior living facilities.

The Gen Xers and Echo Boomers as well tend to demand more urban lifestyles with a propensity towards remaining single and starting families late.

The fastest growing household demographic is that of childless couples, non-family and single person households.

All tolled as many as 65% of new households will be candidates for something other than the traditional suburban cul-de-sac house.

In addition surveys have shown preferences for “new urbanism”, and urban mixed use developments have been able to achieve higher rents per square foot than suburban developments in recent years.

A recent AIA survey featured on www.builderonline.com confirmed the demand for urban infill development over suburban development: http://www.builderonline.com/green-building/infill-invasion.aspx

As professionals devoted to responsible land use we welcome the current surge towards urban living and look for it to remain strong as a sustainable development strategy.

In December, 2009, the USEPA issued guidance on meeting Section 438 with two purposes:  first, to define “maximum extent technically feasible;” and second, to adopt a process for restoring or maintaining the predevelopment site hydrology.  The method is Low Impact Development (LID), a design technique in which treatment measures are integrated throughout the site layout to capture stormwater as close to where it falls as possible.  These pockets of retention and treatment help recharge groundwater and mimic the natural site’s ability to absorb rainfall before runoff begins (a.k.a. initial abstraction).

The treatment measures, which infiltrate, evapotranspirate and/or harvest and reuse stormwater, are known as “green infrastructure” and a palette of these options are as follows:

• Conservation and/or reforestation of riparian buffers and floodplains
• Infiltration
• Rain gardens/bioretention
• Amended soils
• Tree box filters and flow through planters
• Vegetated swales
• Vegetated medians and islands
• Porous and permeable pavements
• Green roofs
• Rainwater harvesting/cisterns/rain barrels

Part 2 of this series will explore the sizing goals for these measures and how section 438 guidance dovetails with both LEED and the runoff reduction method…

Current standards for water quality criteria in the Commonwealth of Virginia (applicable to all state agency projects and every land-disturbing activity regulated under §10.1-603.8 of the Code of Virginia) target a reduction of total phosphorus and are based on a comparison of existing and post-developed pollutant loading or pollutant removal efficiencies. Percent impervious cover is used to determine pollutant loading in both the performance-based and the technology-based methods and various recognized BMPs are then selected based on assigned pollutant removal efficiencies. To date, BMPs are sized to treat peak discharge rates and rely heavily on the principals of detention time and sedimentation for treatment.

By contrast, the 2007 Energy Independence and Security Act mandates for all federally-owned project sites (>5,000 ft²) that design strategies to maintain or restore the pre-development hydrology of the property with regard to temperature, rate, volume and duration of flow be employed. This aforementioned maintenance or restoration of pre-development hydrology can be accomplished by either controlling the 95^th percentile rainfall event, or by analyzing pre- and post-development hydrographs.  Either way, the federal mandate requires that 100% of the excess runoff determined be either infiltrated, evapotranspired or captured and used.

Similarly, LEED® standards (Leadership in Energy and Environmental Design) for water quality treatment of stormwater runoff require that 90% of the average annual rainfall is treated using acceptable BMPs and that the BMPs used are capable of removing 80% of the average annual post-developed TSS loads. To obtain LEED® credit for stormwater design:  quality control, a stormwater management plan that reduces impervious cover, promotes infiltration or captures and treats the runoff must be implemented.

The focus has shifted from management of discharge rates to management practices focused on volume that better mimic natural systems, i.e., infiltration, evapotranspiration and capture and use. Rather than assuming that retention and sedimentation will primarily treat harmful pollutants liberated by stormwater runoff, regulators are now focusing on mandates to treat entirely on-site the “first flush”; that is, zero discharge of runoff from small (1”-2”) storm events is allowed.  EPA is currently in development of a new stormwater rule which may address performance standards for new and re-development; expanding coverage of regulated stormwater discharges to areas with rapid development; provisions for existing discharges (retrofits); permitting and non-permitting alternatives; and special provisions for Chesapeake Bay and maybe other sensitive waters. Based on the already mandated standards for federal sites and similar philosophies used in LEED criteria, it seems likely that the EPA will use a similar philosophy in development of the new rule.  We’ll be tracking the progress of this new rule and you can, too, at www.epa.gov/npdes/stormwater/rulemaking.

Traditional fescue/bluegrass lawns are not native to this area and currently do not qualify for LEED® habitat re-establishment credit in Virginia.

Researchers like Pennington Seed are continually experimenting to develop the best alternatives to the manicured lawn……which requires three times the water of shrub beds, weekly mowing for six-eight months of the year and continuous fertilization.

At Timmons Group, we are always looking for the solution that saves money and, at the same time, enhances the quality of the site. We have found a couple of real winners:

Slopemaster™

• Slopemaster™ has traditionally been used for slopes that are greater than 3:1 and considered un-mowable. The beauty is that this seed mix works on flat slopes with minimum maintenance requirements, and qualifies for habitat re-establishment credits.
• Clover is the dynamic ingredient in the mix. Clover has stolons and will colonize the open areas between the bunch-type grasses to increase cover factor and reduce erosion.
• Slopemaster™ is more heat and drought tolerant than Kentucky Blue Grass or Perennial Rye Grass.
• Slopemaster™ can be seeded year round, as there is a warm and cool mix, eliminating the need for two seedings (temporary seeding/final seeding) with a fescue/bluegrass mixture.|
• Price comparison-Final Seeding For a savings of $31 / acre you can have a truly sustainable vegetation mix for your slopes that includes perennial grasses, legumes (clover), 10% PRG –as a nurse crop- and is treated with mycorrhizae and Germ Max seed enhancements as well.
  - 60/40 (KBG/PRG) @ 200 # / ac @ $1.75/# = $350 / acre
  - Slopemaster @ 75# / acre @ $4.25/ # = $319 / acre
• Price comparison-Erosion/Sediment Control Seeding will cost $315/acre using the warm season or cool season mixes at 75#/acre. This provides approximate savings of $100 per acre over the cost of traditional seeding recommended by VA E&S guidelines for Low Maintenance Slopes in the Piedmont (108# Fescue, 2# Red Top, 20# Crown Vetch and 20# nurse crop), while also providing an improved stand of sustainable vegetation.

Flexterra® Flexible Growth Medium™

• Flexterra utilizes Thermally Refined® wood fibers, crimped man-made fibers and performance-enhancing additives.
• Flexterra has been approved by VDOT as an alternative to blankets with superior erosion control and has proven faster germination rates.
• Nutrients and organics can be added to the hydro-seed mix to save manual distribution and dollars.

Evolving technical advances in habitat establishment support our goals of achieving stewardship and restorative landscapes.

Contributors: Lu Gay Lanier and Neal Beasley

Answer: You don’t!

When the 11-acre site of the historic Richmond Steel buildings was developed into a movie theatre with over 650 new parking spaces, existing buildings and rail tracks were highlighted to earn state and federal historic tax credits, and several thousand cubic yards of dirt had to be hauled off to effectively drain the site.

One of the greatest challenges with redevelopment is working within the constraints of the existing conditions. Rehab and infill sites are surrounded on all sides and often encompass fixed objects, where elevations and site improvements must be designed to fit into the existing framework. This is evident as you view your urban surroundings and notice sidewalks and entrances that are warped beyond belief as well as sites with unusual grade changes, retaining walls and other oddities. These items were likely retrofits and rehabs that were forced into unique configurations to meld with existing features. Storm sewer and utility connections are also limited by what existing infrastructure has to offer, providing another unique set of challenges when designing infrastructure. Including architects and engineers on your team who have the experience and expertise required to successfully deliver re-development projects helps to ensure the ultimate quality of the re-development.

A Phase III Environmental Site Assessment (aka a site remediation plan) can be accomplished in a streamlined process that often integrates nicely into the early phases of property development; I’m not saying this is going to necessarily be cheap, but it’s likely not going to be as horrific as you may have initially imagined.  Besides, you’ve already invested significant time and money into the project, so to redirect your efforts toward another property will likely cost you about as much as the Phase III anyway.  And aside from the inevitable, long-term return on your investment, you’ve just tapped one of the best PR options for marketing imaginable…because everyone wants to occupy the fashionably “green” building that was constructed on a Brownfield site.  Such projects create a good image for you, your future tenants, and the municipality – and for that, you stand to get some great media attention, not to mention the potential LEED points you’re going to get out of this.  And speaking of Brownfields, consider that completing a Phase III ESA could also provide you with additional funding through state reimbursement programs, a federal Brownfield grant, or potentially both.  So see, it’s not that bad – in fact, in some ways you might make out better than you thought.   And finally, the best part… contaminated property is cheap.

Sustainable

Rehabilitation of an existing structure or the re-development of property that has already undergone some use will decrease the need for urban sprawl, deforestation and other impacts to our natural surroundings.

I’ll use two examples:

1. In a dense urban setting sits a half-acre infill lot. The site is slated for a 30-unit apartment building with a large retaining wall. Due to the infill nature of the site, it will never provide substantial wildlife habitat or public recreation opportunities. This site is a prime candidate for a low impact development project. By putting 30 units on this parcel, the demand for a new green-field suburban apartment complex is decreased, replaced instead by a housing option that does not require deforestation or impacts to farmland.
2. A five-acre site in an existing urban industrial park has a creek running right through the middle of it. The owner desires to impact the creek by installing 200 linear feet of culvert pipe in order to create vehicular access to the opposite half of the site, which is currently inaccessible. Allowing the owner to improve his already developed site in the City helps reduce the demand for a new suburban industrial complex outside of the City’s current development footprint.

Land development is necessary for the growth of society, yet any new development that is not re-development or urban infill development will require deforestation and/or other negative impacts to previously untouched natural environments. Using every possible opportunity to recycle land that has already undergone some type of development allows us to continue development without increasing our impact on the natural environments that we cherish.

The flow through planter has become a regular tool utilized in conjunction with green roofs, cisterns, bio-retention and traditional basins.  The close coordination between civil engineers, architects and landscape architects from inception of the project enables the team to:

• Correctly size the planter according to capture area and quantities,
• Incorporate design with architecture for optimum aesthetics,
• Utilize required buffer and foundation plantings for uptake of nutrients, and
• Specify plantings that are tolerant of wet feet for up to 24 hours.

In designing DASH, an infill maintenance facility in Alexandria, Virginia, Timmons Group was challenged by the minimal space available for stormwater treatment.  To design an effective solution within this limited area, a flow through planter was used to capture the first inch of rainfall for pre-treatment and detention prior to entering a traditional basin.  The basin was able to be greatly reduced in size due to the successful design and fit of the planter in a tight space between the sidewalk and building.

The typical detail was updated to obtain enhanced horizontal flow of water from the roof drains to ensure that all plantings were getting equal saturation.  Emergency overflow measures were specifically designed to accommodate any additional precipitation.

Let us know your experiences both positive and lessons learned.  Continue to follow this thread for more on flow through planters; future discussions will focus on specifying planter components, mid-Atlantic plantings for use with flow through planters and long term maintenance requirements.