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by Stuart Toraason, PE, LEED AP
Friday Jun 25, 2010
Recent economic times have left many of us scratching our heads trying to figure out where the next wave of work is going to come from for those of us in the construction industry.
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.
Tags: infill, mixed-use, new urbanism, redevelopment, urban
Posted in Urban Redevelopment
by Charlene Harper, PE, LEED AP
Monday Jun 7, 2010
The Energy Independence and Security Act of 2007 is an “omnibus energy policy law that consists mainly of provisions designed to increase energy efficiency and the availability of renewable energy.” Amid the provisions requiring a CAFE standard 35 mpg by model year 2020 and a 30% decrease in total energy use in federal buildings by 2015 is a small paragraph called Section 438. Section 438 simply states that federal facility development projects exceeding 5,000 sf must use site planning, design, construction and maintenance strategies to maintain or restore, “to the maximum extent technically feasible,” the predevelopment hydrology of the site. This is a far bigger deal than it might appear at first reading.
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…
Tags: bio-rentention, green roof, Low Impact Development (LID), Reforestation, renewable energy, runoff, Stormwater Management, Stormwater Regulations, swales
Posted in Stormwater Management, Sustainability
by Aislinn Creel, EIT, LEED AP
Friday May 28, 2010
A paradigm shift is occurring in the way in which we control pollutants generated by stormwater runoff. This shift is evident by examining the existing and proposed stormwater regulations and design standards. Stormwater runoff (non-point source) pollution is one of the most difficult to quantify and manage, yet critical when it comes to protecting our receiving waterways from harm.
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 95th 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.
Tags: LEED, runoff, Stormwater Management, Stormwater Regulations, water quality
Posted in Stormwater Management
by Lu Gay Lanier, LA, FASLA, LEED AP
Tuesday May 4, 2010
Envision a new paradigm in site master planning where there is little manicured lawn. Native and adaptive trees and shrubs are massed as reforestation, placing a strong focus on healing the land with regional ecosystems. Knee high sweeping meadows require mowing only once a year. Design elements work to mimic or model the surrounding natural systems.
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
Tags: Landscape Architecture, Lawn Alternatives, Meadow, Native Plants, Reforestation, Slopemaster
Posted in Environmental, Landscape Architecture, Stormwater Management
by Stuart Toraason, PE, LEED AP
Monday Apr 5, 2010
Question: How do you engineer a grading plan with a cut-fill balance when designing a site around unearthed historic railroad tracks, existing active railroad tracks, existing high voltage transmission towers and two existing historic building structures?
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.
Tags: land development, redevelopment
Posted in Urban Redevelopment
by John Russell, PG
Thursday Apr 1, 2010
OK, the results of the Phase I ESA were a bit alarming, but you hung in there for the Phase II ESA and then, to your utter dismay, the most disconcerting words you could imagine showed up at the end of the report – contamination and remediation. Now, before you reach for the aspirin and the antacid, you can get through this, and we environmental professionals are here to help.
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.
Tags: Due Diligence, Phase III Environmental Site Assessments
Posted in Environmental
by Stuart Toraason, PE, LEED AP
Friday Mar 5, 2010
Sustainable…LEED…green…LID…these terms have become industry marketing buzzwords, but what are their true meanings? Many who have pondered the importance of these concepts will quickly understand that urban re-development and urban infill development are, by their nature, the most low impact types of land development available.
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:
- 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.
- 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.
Tags: infill, land development, redevelopment
Posted in Urban Redevelopment
by John Russell, PG
Monday Mar 1, 2010
So you’ve had a Phase I ESA completed and the lousy environmental professional you retained is recommending the completion of a Phase II ESA because of some dark episode in the history of the property – let’s say a gas station occupied a corner of the property in the 1950’s. Your initial thoughts probably focus on unnecessary spending and meeting the deadline of your due diligence period – after all, this project was supposed to be easy right? But let’s revisit what due diligence is; yes, it’s required by the bank to make sure that the money they’re lending you won’t be at risk, however, and perhaps more importantly, jumping through the due diligence hoops also serves to protect you from incurring unnecessary liability – for example, when you hit that patch of petroleum contaminated soil while digging your footers and the construction workers suddenly and collectively swear that they show signs of benzene poisoning. Or better yet, tenants, in the future, start smelling petroleum vapors and you never even considered installing a vapor barrier beneath the foundation slab. It all comes down to up-front spending for long-term security, and the assurance of knowing that the property is free of environmental issues by collecting soil and/or groundwater samples for analysis, is well worth the time and money. Trust us on this – ‘cause we’ve likely seen more contaminated property than you have.
Tags: Due Diligence, Phase I Environmental Site Assessments, Phase II ESA
Posted in Environmental
by Stuart Toraason, PE, LEED AP
Friday Feb 19, 2010
Urban infill and re-development projects require special means of minimizing increases in stormwater flow is to implement innovative sustainable design techniques to increase pervious area and improve rainwater retention. Projects like Timmons Group’s LEED® Gold certified 1050 K Street project in DC use green roofs, planter beds and rainwater harvesting to meet city code and minimize impact to the combined sewer system.
Projects that involve large-scale infrastructure updates are often required to separate the storm and sanitary sewers as the project progresses. Rocketts Landing in Richmond, Virginia, is a good example of this. In this case, the existing combined sewer system was designated solely for stormwater runoff, and a separate sanitary sewer system was created by constructing new sanitary mains and connections. Stormwater runoff was treated on site and discharged directly to the James River, while the sanitary sewage was directed to the treatment plant.
Combined sewer systems do have one benefit from a development standpoint, in that most local jurisdictions, as well as state and federal codes, do not require stormwater quality control since the stormwater runoff flows to a municipal treatment plant. In addition, for projects in localities that control stormwater quantity, previously mentioned sustainable design techniques may be implemented to eliminate any stormwater increases; thus, the end result can be that stormwater management is not required at all.
Tags: combined sewer, infill, land development, sanitary sewer, Stormwater Management
Posted in Urban Redevelopment
by Lu Gay Lanier, LA, FASLA, LEED AP
Wednesday Feb 10, 2010
The integration of stormwater treatment for quality and quantity is always challenging on an urban site where traditional treatments require acreage that is simply not available. To meet current regulations, the design team needs to look at creative options for removal of pollutants and detention of rainfall within a restricted area.
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.
Tags: bio-rentention, Landscape Architecture, planters, Stormwater Management
Posted in Landscape Architecture, Stormwater Management
Recent economic times have left many of us scratching our heads trying to figure out where the next wave of work is going to come from for those of us in the construction industry.
