NOTE: I suggest
printing this essay so you can place the tables next to the text for reference.
Tables 1-3 document the conflict. Tables 4-7 are forecast models that present
an algorithmic alternative. They are part of a comprehensive portfolio implied
by Table 8, and eliminate conflict by automatically correlating independent
regulations to reveal their combined implications. They represent the formation
of a new leadership language that can lead a response to the issue of shelter
for the activities of growing populations within a Built Domain that is
geographically limited to protect their source of life, and is designed to
protect their quality of life. The models represent one small step toward the
absolutely essential goal of symbiotic survival. This is a document you must be
prepared to study. It is not meant to be easy reading on the editorial page. It
is meant to stimulate your interest in a new science - the Science of City
Design.
SINGLE FAMILY ZONING
Table 1 is a collection of residential zoning regulations distributed
through the chapters of one zoning ordinance. Lines 14-29 apply to single
family residential lots. Lines 31-91 are written for multi-family buildings,
but also permit 1-4 family housing.
Minimum lot areas per zone are noted in column F. Building
height regulations are noted in columns C-E. Maximum net densities are noted in
column H. Lot width, depth, and setback requirements are noted in columns J-P.
Parking requirements are noted in column Q.
None of these requirements are correlated. Each is
independent and their combination has often produced conflict and contradiction
that has defeated consistent design leadership. The dilemma is most easily
explained by asking one question:
1) Is it possible to achieve the net densities
permitted in column H given all of the remaining independent requirements on
any given line of Table 1?
Table 2 lays the ground work for an answer by calculating
the implications of the zoning requirements in Table 1. Column HH gives the
impression that the total gross building area potential for each zone is more
than adequate. Column JJ shows that unpaved open space is a quantity that
remains after all impervious cover topics are subtracted. It is not a
requirement. It is a left-over quantity and cell JJ14 reveals a typical
contradiction. The 3 acre R1 zone is intended to be the lowest density zone in
the city; but when the independent line item requirements in Table 1 are
analyzed, cell KK14 shows that they permit the highest percentages of
two-dimensional building and pavement cover (impervious cover) in the
community. This means that the lowest density is permitted to produce the
greatest intensity.
The collection of requirements on line 14 of Table 1 also permit
the greatest amount of three-dimensional gross building area as shown in cell HH14
of Table 2. Homes in the R1 zone are expected to be larger; but the maximum 158,610
sq. ft. shown in cell HH14 is far greater than needed for a single family
detached residential home and contradicts the low density intent. Column JJ in
Table 2 also shows that total left-over yard areas increase as density
increases. This exposes another contradiction of expectations.
Column KK also reveals a more dangerous permitted condition.
A residential storm sewer is often designed to accommodate the runoff from 30%
impervious cover, but the actual percentages are often omitted from the public
record. The percentage reduces initial pipe size and construction cost, but may
not be correlated with zoning requirements that govern site plan preparation
for building cover, pavement, and yard area quantities. Column KK in Table 2 shows
that all permitted site plan impervious cover percentages in the column exceed
30%. Problems can begin when storm sewer design capacity percentages are not
correlated with zoning ordinance regulations and recorded on approved plats.
When permitted impervious cover excesses multiply along branch and trunk sewer
lines with limited storm water capacity, flooding becomes inevitable and
continues until a city can afford to construct relief sewers. In other words,
the impervious cover percentage limits permitted for site plans in column KK
should not exceed the design capacity of the storm sewer system present,
planned, or permitted.
Table 3 measures the implications of Tables 1 and 2. The
underlying question is the meaning of the measurements. For instance, the most
obvious implausibility is on line 14. It pertains to the low density R1 zone,
but permits some of the greatest shelter capacity (SFAC), intensity (INT),
intrusion (INTR), and dominance (DOM) measurements in the table because of the
zoning regulations in Table 1. This is a classic example of inadequate or
nonexistent correlation that can occur between zoning regulations and city
design results.
The measurements in Table 3 imply two additional questions:
2) What measurements and percentages are
desirable?
3) How can regulations be correlated to avoid
leadership contradictions?
I won’t attempt to answer Question (2). It will require site
plan measurements and evaluation of hundreds, if not thousands, of existing
site plans and building mass relationships before conclusions can be reached
with the credibility required for public acceptance. When accepted, these
conclusions will establish desirable, correlated parameters with the potential
to lead the design and construction of shelter for the activities of growing
populations within a geographically limited Built Domain. This will protect
their quality and source of life – The Natural Domain.
Correlation is the objective of Table 4 and the answer to
Question 3. Cell F3 defines the actual land area involved for this example.
Cell F12 defines the shelter area available for “improvement” in cells F12-G12
after the percentages entered in the boxes of the Land Module produce
quantities that are subtracted. (Any value entered in a box within the table is
a variable that may be changed to explore options.)
Cells F15 through F19 define the design standards being
tested. Line 23 introduces additional design decisions that apply to the proposal.
Line 38 calculates the implications of all design values
entered in the boxes of the Land and Shelter Modules. Line 43 presents these
calculations. The impervious cover value representing the sum of these building
and pavement cover decisions is presented in cell J48. The bonus room above the
garage is added in cellK38. Garage and accessory building areas are added in
cell L38 to produce total building area (TBA) in cell L38. All of these values
are presented on line 43.
Cells A53 to A74 contain unpaved open space percentage
options. The shelter area density that can be achieved in column F of the
Density Module is a function of the average impervious cover per dwelling unit
value (AVGIMPD) presented in cell J43 and the unpaved open space per dwelling
unit value (UOSD) chosen in column A of the Density Module. (One minus the
UOSD% in column A should coincide with the storm sewer capacity present, planned,
or permitted.)
The density results in cells F53 to F74 serve to explain
that density is not a leadership tool. It is a result of the 45 correlated
design decisions displayed in the boxes of Table 4. The choice of design values
in these boxes is up to you until research defines better parameters. Table 4
is simply an algorithmic tool that correlates these decisions to give you the
vocabulary and language needed to lead shelter design decisions toward your
design objectives.
The total impervious cover required for the home specified
on line 23 of Table 4 is presented in cell J43. When this 2,700 sq. foot area is
combined with the 9,300 sq. ft. of unpaved open space in cell B68, a 12,000 sq.
ft. lot is produced containing the 77.5% of unpaved open space, or 9,300 sq.
ft., noted in cell B68. This total complies with the minimum lot area required
by the R6 zone. Column D in the Density Module also shows that the home would
fit in five other zones when the unpaved open space percentage in column A is
adjusted as noted. If you look at column EE in Table 2, however, the impervious
cover pertaining to these zones in the current ordinance is substantially
greater. So who is right? If the impervious cover capacity of the storm sewer
is 30%, line 66 in Table 4 is right and Table 2 represents serious excess.
I should also mention that line 29 in Tables 1-3 was
rejected by the community in 1968 as a minimum living standard. It permitted
53% impervious cover and the desire for larger home sizes on these small lots
led to variance requests that were often permitted. These variances increased
impervious cover, reduced open space, and eventually led to the need for a
relief sewer at public expense. These variance approvals were often combined with
additional variance requests to reconcile conflicting regulations. The
combination of increasing intensity, decreasing open space, and inadequate
infrastructure eventually led to rejection of the R7a zone on line 29 of Table
1, but left the lots as a lesson that was not fully understood.
Based on my experience, unpaved open space on a given lot or
land area is a by-product and not a conscious zoning requirement adopted to
protect a city’s storm sewer capacity and quality of life. The minimum amounts
needed to function as a relief from intensity and a contribution to a city’s
health, safety and quality of life has often been considered a “taking” of
property value; but who is taking what from whom? The lack of knowledge
regarding the value of unpaved open space and the arbitrary nature of
uncorrelated zoning requirements leaves an entire city at the mercy of uninformed
regulations and variance approvals.
Forty-five values have been entered in the boxes of Table 4
and have been correlated by an algorithm and master equation to produce the
results in its Density Module. The specification values entered are interactive
and one or more may be modified to produce different results in the Density Module,
but the underlying point is that correlated zoning requirements are the key
to effective city planning and design leadership.
A measurement system has been introduced in columns H-L of
the Table 4 Density Module to calibrate the implications of correlated zoning
requirements. Line 66 shows that the minimum preferred single family
residential standard in the R7 zone produces 15,379 sq. ft. of gross building
area per shelter acre, an intensity of 0.106, intrusion of 0.4, and dominance
of 0.506 per shelter acre when the minimum unpaved open space percentage is 70
and the total home area in cell K43 is 2,598 sq. ft.
Cell H66 in Table 4 reveals a contradiction with cell GG28
in Table 3. Table 4 shows that the R7 zone on line 66 can produce 15,379 sq.
ft. of shelter area per acre based on its design specification. Table 3 shows
that the R7 regulations on line 28 of Table 1 can produce 36,421 sq. ft. of
total shelter area per acre. The intensity represented is 0.446, intrusion is
0.5, and dominance is 0.946. Keep in mind, however, that Table 3 represents
unintended consequences produced by uncorrelated zoning regulations.
The answer to Question 1 is that achieving a net density
limit produces random results when the 45 leadership decisions in the boxes of
Table 4 remain ignored or uncorrelated. The density options in column F of
Table 4 are based on these 45 correlated decisions. In other words, density
is a social measurement that is a product of many physical design decisions.
Question 2 remains to be answered with the measurement,
correlation, and evaluation of existing projects based on the consistent topics
of a shelter capacity and intensity forecast model.
In response to Question 3, zoning regulations can be
correlated to avoid leadership contradictions and achieve leadership objectives
with shelter capacity and intensity forecast models.
MULTI-FAMILY ZONING
Lines 32-91 in Table 1 were originally written to address
multi-family residential shelter options that I’ll generically refer to as
townhouses and apartments. “Townhouses” are horizontally connected single-family
residential dwelling units that are not stacked. “Apartments” are connected and
stacked dwelling units within a gross building area envelope.
Townhouses
Table 5 is similar to Table 4, except for lines 23-27 and
lines 38-42. Design value options have been entered in lines 23-27 to reflect
the diversity of bedroom options often available in townhouse configurations. (These
additional values could also be changed to reflect home size options in a
residential subdivision.) Lines 38-42 calculate the implications of lines
23-27. Lines 53-71 correlate these implications with a master equation to
produce the results in the Density Module. The density options related to these
correlated design decision values are displayed in cells F53-F71 of the Density
Module.
Column F in the Density Module of Table 5 illustrates that
density is a function of the 67 optional design values entered in the Land and
Shelter Modules of Table 5, and a choice among the unpaved open space
percentages entered in column A of the Density Module. If 5% open space is considered,
a density of 21.33 dwelling units per shelter acre can be achieved as noted in
cell F53, but this is based on a limit of 5% unpaved open space. If 50% open
space is provided, a density of 11.23 dwelling units per shelter acre is
achieved on line 62 based on the design specification in the Shelter Module.
The point is to illustrate that correlated open space percentages and design
specifications produce the density limits in column F of Table 5. Keep in mind
that each open space increment in cells A53-A71 has a companion storm sewer
capacity percentage equal to 1-UOSD% in cells B53-B71. An engineering
standard does not necessarily represent an open space provision that protects
our physical, social, psychological, environmental, and economic quality of
life, however. The measurements in columns H-L of the Density Module have
been created to measure these implications.
Apartments
Table 6 is a variation of Tables 4 and 5. It has been
adapted to address the unique nature of apartment design decisions. The Land
Module calculates the shelter area available in cells F12 and G12 based on the
values entered in its boxes. The G1 Module identifies the net shelter area
available in cells F20 and G20 after a number of miscellaneous site plan topic
values are entered and subtracted. The Apartment Module defines the “mix” of
bedroom types, percentage allocations, and habitable areas under study in cells
A30-C34. The building efficiency percentage entered in cell F36 is used to
convert habitable area to gross building area per dwelling unit type in cells
D30-D34. The garage and parking lot spaces planned per dwelling unit type are
entered in cells E30-F34. The design averages representing the dwelling unit
mix are calculated on line 36. These are correlated with the open space
percentage options in column A and the building height options on line 44 of
the Density Module to produce the density options in cells C46-M64. (The
correlation is executed with a master equation.)
Table 6 illustrates the number of density options that can
be produced from one design specification when unpaved open space and floor
quantity options become variables. The specification is represented by the
values entered in the boxes of the Land, G1, and Apartment Modules of Table 6.
The unpaved open space options have been entered in cells A46-A64. Floor
quantity options have been entered in cells C44-M44. Density options are
located in cells C46-M64. A choice is made by finding the intersection of an
unpaved open space percentage and a floor quantity option. The density located
represents the correlation of 68 design specification decisions in the Land,
G1, and Apartment Modules plus the unpaved open space and floor quantity
decisions in the Density Module. Intensity and Dominance measurements
corresponding to the density options found in Table 6 are calculated in Table 7.
The point of this apartment exercise is to show that the
density of 34.85 permitted in cell G74 of Table 1 is questionable given a
complete design specification containing 70 decisions. It cannot even be found
in cells C46-M64 of the Density Options Module in Table 6. In addition to this,
the intensity and dominance measurements calculated in Table 7 indicate that
many of these choices are not desirable; but this conclusion is based on my
opinion, and it will only convince others when supported by consistent
measurement and evaluation of many existing multi-family residential apartment
projects based on a standard specification vocabulary and language.
OPPORTUNITY
Compilation, correlation and consistency of planning data
evaluation can yield city design knowledge. This is the opportunity implied by
Tables 4-7. Table 8 has been created from Table 4 by removing all calculation
line items. The data entry boxes remain to form a questionnaire for the G1.R1
Activity Group. The intent is to use this modified forecast model to record existing
and proposed shelter project data for evaluation. If the residential activity
topics were removed, it would e a questionnaire for the G1 Design Category.
(The gross building area options for a design category can be used to shelter
any activity.)
A completed questionnaire represents a project data record.
Record values can be entered in a related forecast mode. Tables 4-7 have been
examples of forecast models that calculate shelter design and impact
implications. For instance, columns B-F in Table 4 calculate design
implications based on 23 design decisions and 22 floor quantity choices. Many
more design implications could be calculated, but these have been presented as
examples.
Columns H-L in Table 4 calculate the impact represented by
the 23 design decisions and 22 floor quantity options in the table. Impact is
measured by calculating the shelter capacity, intensity, intrusion, and
dominance represented by the design specification and each floor quantity
option in the Design Module. The data in the module implies a question:
What impact parameters on the 22 lines of
the Density Module are undesirable?
Given the incomplete and conflicting nature of
current zoning regulations, this remains a land owner driven decision without a
correlated city design strategy and land use policy. Project records,
evaluation, and city design forecasting can begin to answer the question when
all members of the shelter design and construction community begin to use a
common, cloud-based method of preliminary planning and evaluation. I have the
models if someone wishes to invest in the application.CONCLUSION
You have just read about the G1.R1 (single-family), G1.R2
(townhouse), and G1.R3 (apartment) activity groups. The S1.R3 activity group
represents an apartment building served by an adjacent parking garage on the
same property. The parking capacity of the S1 garage influences the gross
building area potential of the site. Gross building area is subdivided by an
apartment design specification to determine the apartment capacity of the gross
building area. If an S1 design category building became an initial design
decision, the Table 6 forecast model would be replaced by another. The floor
quantity options in the new model would be changed, and the density options
calculated would increase significantly. These optional building categories are
not anticipated by the density regulations in Table 1. This omission, and the
omission of unpaved open space specifications, means that a developer may seek
to achieve these permitted high densities with a surface parking lot. The
attempt can produce a sea of asphalt around a tall building with no open space
relief in sight and little attention to storm sewer capacity.
POSTSCRIPT
I have used a number of terms in the Conclusion without
definition. Table 9 places them in context with a Built Domain classification
system that includes an explanation of their meaning.
TABLE 9: Classification
of The Built Domain
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||||||||
A
|
B
|
C
|
D
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1
|
Definitions:
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2
|
The Built
Domain: All physical creations of man on
planet Earth
The Natural
Domain: All of planet Earth, except The
Built Domain
Phylum:
one of two elements of The Built Domain
Division:
one of four components of a Phylum
Cohort:
a primary unit of a division encompassing similar, but not necessarily
compatible, activities
Category:
A primary unit of a cohort with a unique physical feature such as, but not
limited to, a parking system
Group:
A unit within a category containing similar activities or functions
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|||||||
3
|
Phylum
|
Urban, Rural
|
||||||
4
|
Shelter
Division
|
|||||||
5
|
Cohort
|
Residential, Non-residential
|
||||||
6
|
Category
|
G1: Surface parking around, but not under,
building
G2: Surface parking around and under
building
S1: Structure parking adjacent to building
on same premise
S2: Structure parking underground
S3: Structure parking at grade under
building
NP: No parking
required
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7
|
Group
|
R1: Single-family detached, unstacked
residential
R2: Single-family attached, unstacked
residential
R3: Single family attached, stacked
residential (apartments)
NR: Non-residential occupant activities are
too extensive to separately itemize, and may require customized design
specification templates.
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8
|
Characteristics
|
|
||||||
9
|
Movement
Division
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|||||||
10
|
Cohort
|
Roads, railways, air traffic, water traffic,
subways, bikeways, sidewalks, and so on
|
||||||
11
|
Category
|
Airborne, terrestrial, aquatic, and
subterranean
|
||||||
12
|
Group
|
Intercontinental railways, short-haul
railways, international airlines, local airlines, intercontinental shipping,
local ferries, intercontinental tunnels, local subway systems, and so on
|
||||||
13
|
Characteristics
|
Location
Function: (e.g., local, collector, arterial and freeway road systems)
Service Level: level of demand or
design
|
||||||
14
|
Open
Space Division
|
|||||||
15
|
Cohort
|
Federal, state, regional, local and
private
|
||||||
16
|
Category
|
Preservation, participation, defense,
and buffer
|
||||||
17
|
Group
|
Campgrounds, day visits, lodges,
proving grounds, and so on
|
||||||
18
|
Characteristics
|
Location
Function: active, passive, restricted,
or prohibited use
Service Level
|
||||||
19
|
Life
Support Division
|
|||||||
20
|
Cohort
|
Agriculture, energy, communication,
health and safety
|
||||||
21
|
Category
|
Airborne, terrestrial, aquatic, or
subterranean
|
||||||
22
|
Group
|
Farms, hydro-electric dams, sewer
systems, water systems, power systems, communication systems, medical
systems, food systems, and so on
|
||||||
23
|
Characteristics
|
Location
Function: active, passive, restricted,
or prohibited use
Service Level
|
||||||
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