Discussion Item: Density Transition Standards

Over the coming months, Planning Staff will be bringing forth various discussion topics to the Planning Commission to consider potential updates to the Zoning Code (needed to ensure that the Zoning Code successfully achieves the intended outcomes of the Comprehensive Plan).  One such topic is Density Transitioning, which is required when a higher density development is proposed adjacent to an existing, lower density neighborhood.  While there are multiple options to satisfy Density Transitioning, landscaping (or preservation of existing trees) is almost always the tool utilized.  However, there are challenges with the current Density Transitioning standards and ideally, the standards could be modified to alleviate some of the more common issues.

Notification is not required.

This discussion will be broken down into segments, to help provide Staff detailed feedback on various aspects of the current regulations.

Quantity of Plantings
Depending on the zoning of the proposed and existing developments, the quantity of trees, which must be a mix of overstory, ornamental, and evergreen trees, varies.  It can range from a minimum of six (6) trees per 100 feet of common boundary with an existing development up to forty-eight (48) trees per 100 feet of common boundary with an existing development, dependent on the zoning of the proposed development and that of the existing neighborhood.  The width of this corridor also varies (again, dependent on the proposed and existing zoning), which helps somewhat finding more space to plant these trees.  However, often, trees end up being planted too close together in an attempt to meet the minimum numbers.  As the trees mature, there will not be sufficient space to grow, there will be significant competition for water, nutrients, and sunlight.  

Question: Should the City consider reducing the required number of plantings to satisfy the Density Transitioning standards?

Common Ownership
The intention is for the Density Transitioning area(s) to be held in common ownership, which does make sense if the proposed development is a multifamily project, as they generally have a Home Owners Association (HOA).  However, when a proposed 'urban' single family development is proposed adjacent to an existing rural neighborhood, the common ownership standard is more difficult.  Many single family developments do not have (or need) an HOA, thus, the common ownership standard cannot be achieved.  While the City could require an HOA for maintenance of the 'common area', it is very likely that the HOA would dissolve, leaving no clear party responsible for maintenance.  In a recent development, the Density Transitioning area ended up being divided into multiple outlots that were deeded to the City (with the intention of the City deeding the outlots to the adjacent, existing property owners).  This puts more burden on the City to maintain these areas for the long term and requires the allocation of resources, which are already stretched thin.

Question: Should the common ownership requirement be reconsidered?

Existing Trees Off-Site
Under current standards, only trees on a project site can be credited towards the Density Transitioning standards.  However, oftentimes, there is significant tree cover abutting a project site that already provides relatively good buffering or transitioning.  Additionally, that existing tree cover further restricts growing space and represents even more competition for water, nutrients, and sunlight.

Question: Should existing conditions off site be considered or included as part of the Density Transitioning standards? 

Definition of and Standards for Berming
City Code currently defines a berm as an "earthen mound designed to provide visual interest, screen undesirable views, and/or decrease noise".  Per current Density Transitioning standards, if a berm is included, the required number of plantings can be reduced.  However, City Code Section 117-110(2)b.4. states that berms cannot exceed six (6) feet in height.  There is no minimum height specified for berms.  Berms can also be challenging if there are existing trees off site, but near the property line.  The equipment used to construct the berm can compact soil, resulting in the potential decline in the health of existing trees.  Furthermore, by adding more soil, there will be less oxygen in the pore spaces, which is something that roots need (similar effect as planting a new tree too deeply).

Questions:

• Should the definition of a berm be updated to specify that it must extend above the existing grade?
• Should a minimum height be specified for a berm?
• Is a maximum berm height necessary (or as long as it complies with allowable slope standards, does it matter?)? 

Alternatives to Landscaping
Presently, there is no specific consideration given to other forms of screening, such as privacy fencing.  Staff is assuming that the required number of plantings may have been originally set due to the size of trees at time of installation.  Evergreens are required to be six (6) feet in height; overstory trees are required to have a caliper of at least 2.5 inches; ornamental/understory trees are required to have a caliper of at least 1.5 inches.  Even when planted really close together (for example, 10-15 feet on center), they still don't provide a significant amount of screening/buffering for an existing neighborhood.  It can take years for the trees to 'fill in' and accomplish their intended purpose.  

Question: Should privacy fencing be considered as an option (along with some landscaping and possibly berming)?
 

This is being handled as part of Staff's regular duties.

Provide Staff feedback on the various questions and aspects of the current Density Transitioning standards.