A Better Arrangement
Over the past three decades, the digital industry has revolutionized the way surveyors work in the office and in the field. Now, new technology for subdivision design will alter the landscape itself.
Coving is an exciting new concept for neighborhood planning. Aided by specialized design software, coving takes into account random variances in nature for home and street placement. It eschews grid-like layouts in favor of meandering roads and moves homes back on their lots for a more attractive panarama from the street.
Builders across the country, including five of the nation's top 10, have constructed nearly 200 coved and BayHome developments totaling more than 42,000 lots. Coving achieves several improvements over conventional subdivision planning while costing developers and municipalities less. Coving also promises to translate into a better quality of life and serve as the standard for future cities.
Coving - Higher Single-Family Living
Case Example #1In the conventional subdivision shown above left, the streets are designed paralleling boundaries and wetlands. Excess space is filled with connecting streets or cul-de-sacs. Along the south side of the subdivision, this design highlights ugly home rears along arterial streets. One problem with this form of design is that it produces the maximum linear feet of street, reducing the land available for lots and increasing street construction costs.
Now, let's apply coving, a method that utilizes a more efficient street pattern, which in turn reduces linear feet of street. In a coved layout (above right), the collector street meanders within the site and the fronts of homes form beautiful arcs independent of street curves. These large, park-like, front yard spaces are called coves.
Case Example #2The Meadows of Saddle Creek in Carmel, Ind., represents the typical benefits of coving. This 233-lot development saved 3,400 linear feet of street compared to the conventional plan previously designed before coving was applied. The minimum lot size was just 10,000 sq. ft.
The coved plan appears similar to curved subdivisions common today. But at street level, the impact changes significantly. These are 80 foot-wide lots at the meandering front setback, with setback distances varying between 25 feet and 110 feet.
Now compare this to the view of a conventional subdivision. The homes are close to the street, and cars parked in driveways negatively impact the scene. This repetitive, monotonous view does not create long-term value in a community as coved designs do.
Connectivity and CommunityConnectivity is often a problem in modern subdivision design. Each intersection can jeopardize pedestrian safety and add to overall inefficiency. A movement called New Urbanism believes the best method to connect people and traffic is to revert back to traditional grid design. Unfortunately, grids create even more accident-prone four-ways than the typical subdivision maze shown here.
In contrast, the non-linear pattern of lots and streets available within coving provides a solution that is more in tune with nature's topography. This plan consumes 70 percent less land area in right of way. More importantly, the entire neighborhood is reduced to a single street.
The red connecting areas are walkways wide enough to double as emergency vehicle access routes. This makes the neighborhood easy to walk through and also makes it safer. Compare this to the conventional design at the southeast corner of this plan. The density is within 5 percent of the conventional plan.
BayHomes-Higher Density Single-family LivingOne way to maximize space in a coved community is the use of BayHomes. A BayHome is a marriage of a townhome (condominium) and a single family traditional home. BayHomes differ from other housing forms in two major ways: architectural controls and street patterns.
Architectural ControlsMany traditional homes have alleys in the rear, a street in the front, possibly a porch and very little open space. BayHomes specify traditional architectural controls such as porches and decks, but front the homes onto space, with the openness and enhanced views of coving. Traditional neighborhoods are typically linear with streets and blocks based upon a grid. BayHomes are normally staggered and facing onto arced park-like walkways to provide panoramic views from within the home. Going beyond the traditional architecture, a BayHome's interior space is planned simultaneously with the exterior common areas and window locations. This assures privacy yet offers unparalleled panoramic views, even with homes at close proximity. BayHomes also reverse the unit so that the home front is positioned where the home rear typically is. All living areas are routed towards this front that also has a porch or deck. This front connects to a common walkway. In contrast to New Urbanism or traditional neighborhoods, this creates the largest area of play space for children at the front of the home, instead of at the street.
The first BayHome community, "The Greens," in Hutchinson, Minn. is shown above. Staggering allows side window views; interior living areas benefit from outdoor views, and the kitchen becomes the social center of the home.
Street PatternsThe photograph illustrates that the rear entry access is not a narrow alley but built at private road widths and maintained by the group of homeowners within the development. In this case the width is 24 feet. Rear street cross sections conform to the local multi-family or townhome standards. Two- or three-car garages are sideloaded to further reduce garage impacts.
The houses are a minimum of 40 feet wide, allowing rooms and living areas to orient to the fronts. Window placement and staggering create an enhanced sense of space even though homes shown here are 10 feet apart. In fact, at the grand opening of this community, a prospective buyer peered out the window of the model home and commented, "This view is great but what happens when the home next door goes in?" The agent replied, "What do you mean? It is in!"
Similar to coving, the same non-linear relationship of street to home is used to increase site efficiency. The large open space and walkway define a sense of neighborhood. This site has just 32 percent impervious surface area, yet density is 4.2 units per acre with home sizes over 2,000 square feet. More importantly, these new technologies in planning and coordinate geometry have transformed what would have been another "subdivision of land" into a lasting and graceful neighborhood; a legacy for future generations.
The Method-Higher TechnologyWhile it is possible to freehand sketch coved neighborhoods, it is next to impossible to compute and stake these new layouts without using new field and office technology.
Here's how it works. Advanced design software is used to create home typicals, clusters and street patterns. For our illustrations here, we used SiteComp for Windows (SiteComp, Minneapolis, Minn.), an all-in-one civil/survey software because it uses a coordinate geometry base combined with spatial technology. The spatial-based feature was used to easily calculate areas and linear feet. The last step includes computing lot lines, verifying minimum lot area requirements and producing the final plat. This software eases the creation of a design plan for city approval.
Home TypicalsHome typicals portray example houses that will be built in the community. Phantom lines, which represent minimum setbacks-front, side and rear-are added to these typicals, detailing such elements as driveways. Parcels and shading can be applied for information and graphics.
These homes are put into memory and are called clusters. They are placed accurately in relationship to boundary, topography and each other. Side, rear and front yard phantom lines and corners are joined. In this way, no lot has dimensions less than the ordinance minimums. Home fronts are placed with enough setback to assure that a street will easily wind through the development. Streets are then set in along with paving.
Spatial information, along with the roof top spatial data, makes it possible to easily compute run-off impacts. More homes can be set along a street length when units are set further back than the standard minimums.
The next step is lot line coordinate geometry, achieved by using the phantom layer line as a guide to place side and rear lot lines. By extending lot lines along these guides or through the common point between the guide lines, the subdivision linework and calculations are created simultaneously.
Finally, the software can help the designer verify that all lots meet the city's minimum lot area requirements. Most of the information is shown in final coordinate geometry.
The end result? The software helped to create an impressive plan for the clients, and one that can easily be appreciated (and approved) by council members. More importantly, the plan will produce a spacious and livable neighborhood, a lasting source of pride for both residents and cities.
The Final PlatBelow is a final design plan presented to a city for approval of a U.S. Home Corp. neighborhood in Stillwater, Minn. The plan received favorable comment and quick approvals by city officials.
In a conventional subdivision, the developer must maximize the number of lots in order to maintain a profit. With conventional subdivision design where home fronts parallel the street, density is an absolute function of the number of lots that fit along the front setback at a given width. Local authorities regulate the minimum lot size and dimensions. The surveyor assumes that by using the absolute minimum lot size, maximum density will be achieved, keeping the developer happy.
By using the more efficient coving technique to meander street(s) through the site, the linear feet of street typically gets reduced 20 percent compared to conventional planning methods. By meandering the homes back further than setback minimums to coved setback standards (sometimes as much as 1.2 times lot width at the setback), density should remain similar to the conventional plan. Plus, meandering the streets can create extra distance from boundaries and natural features.
Does this mean that every surveyor will easily be able to produce coved neighborhoods? The most important concept that enables a surveyor to be a good planner is the ability to picture living in each home on each lot and to question whether that location would be desirable. After that, it takes time and practice to get a feel of how coved design works, somewhat like learning to fly a plane. But once it is achieved, repeat performances are simple. And, as verified by increasing customer demand, mastering these concepts will broaden the scope of several businesses.