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3.1 Definition of
and
Because most commercial
should be able to accomplish the ordinance’s 50%
goal using
strategies alone, the following information focuses on data for
.
typically consist of an array of
, each served by a
that provides harvested water to support the plants within it. To meet the city ordinance requirements, the
needs to be designed so that 50% of annual plant water demand is met with harvested
as an average across the
. If the 50% goal cannot be met at some
due to
conditions, then other
should be designed to exceed the 50% goal in order to achieve 50% overall.
are locations at a
from which water is harvested for beneficial use. These locations include areas where rain falls directly into earthen basins and infiltrates into the ground (these are known as
.
also include locations where rain falls on rooftops, sidewalks, parking lots, driveways and other hard surfaces then flows toward
where the water infiltrates into the soil.
The
for any given
Infiltration Area is the ratio between the
serving it and the canopy area of the plants located within it. As one example, runoff from 100 square feet of sloped parking lot and soil drains to a
Infiltration Area that is planted with trees that have a canopy area of 20 square feet (as seen from a bird’s eye view). The
for this example is 100 to 20, which can be simplified as five to one.
3.2 Calculation of
In Tucson, different types of plants need different amounts of water each month because rainfall and temperature vary from month-to-month (Table A-4). Table A-6 shows the
needed to provide harvested water for each square foot of
for different plant types in different months. The data on Table A-6 was calculated using the following equation for each month and each plant type:
needed = Monthly water demand per square foot of plant type
Effective monthly rainfall
PLANT TYPE | SQUARE FEET OF
NEEDED TO MEET WATER DEMAND FOR EACH SQUARE FOOT OF CANOPY AREA | |||||||||||
Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
Very low water use | 0.8 | 1.0 | 1.8 | 7.1 | 10.3 | 10.9 | 1.1 | 0.9 | 1.2 | 1.2 | 1.3 | 0.6 |
Low water use | 1.5 | 2.1 | 3.7 | 14.2 | 20.6 | 21.8 | 2.2 | 1.7 | 2.5 | 2.4 | 2.7 | 1.3 |
Moderat e water use | 2.6 | 3.6 | 6.3 | 24.6 | 35.6 | 37.7 | 3.9 | 3.0 | 4.3 | 4.1 | 4.6 | 2.2 |
High water use | 3.8 | 5.2 | 9.2 | 35.6 | 51.4 | 54.5 | 5.6 | 4.3 | 6.1 | 5.9 | 6.7 | 3.2 |
3.3 Calculation of
In Tucson, plants need around 37% of their annual water supply in the hot dry months of April, May and June. The remainder of their annual water supply, about 63%, is needed in July through March. Figure A-1 illustrates the relationship between plant water demand and effective rainfall supply in Tucson. In April, May and June there is a large gap between plant water demand and effective rainfall supply. There is a smaller, but still substantial gap between demand and supply in March. The rest of the year,
supply lags behind demand, but not as much as in March through June.
By designing a
that has
sized to fully meet March plant water demand, the harvested water supply would typically exceed plant water demand in July through February (Figure A-2). This design strategy provides a cushion in meeting the 50% goal for the
and is recommended by the city as a general approach.
Based on Table A-6, a landscape composed of low water use plant types would need a
of 3.7 to 1 to meet March water demand. This means that for each square foot of
(as seen from a bird’s eye view), 3.7 square feet of
is needed to collect
from. This area includes the dirt
Infiltration Area the plants are located in, and any parking lot, roof-top, or other hard surface around the plant that drains to that area.
It is best to locate plants of the same type in a
Infiltration Area, though
may have different plant types in other
. Table A-6 can be used to determine appropriate
for the plant types used in Tucson.
Annual Water Use Report | ||||
Reporting period (month/day/year): from _______________ to _____________________ | ||||
Project Name | ||||
Project Address | ||||
Owner name | ||||
Report Preparer name Preparer title | ||||
Preparer address | ||||
Preparer email Preparer phone | ||||
Source of rain data (check all that apply): ____on raingage ___ www.rainlog.org station: note the closest cross streets ___________________________________________________ | ||||
Source of metered irrigation water (check all that apply): ___Tucson Water, acct # _______________ ____ water from another water utility ____well water ____ reclaimed water | ||||
MONTHS | RAINFALL (inches) | IRRIGATION WATER USE | ||
Projected landscape water demand shown in the Harvesting Plan (gallons) | Actual metered use (gallons) | Difference (gallons) | ||
January | ||||
February | ||||
March | ||||
April | ||||
May | ||||
June | ||||
July | ||||
August | ||||
September | ||||
October | ||||
November | ||||
December | ||||
ANNUAL TOTAL | ||||
Explanation for any exceedence of annual irrigation water use projected in the approved Harvesting Plan: | ||||
Changes to the landscape or irrigation system in the reporting year: | ||||
AREA BELOW FOR STAFF USE ONLY | ||||
Drought conditions exist at the : | ||||
Compliance with Harvesting Plan: | ||||
Audit required/date/outcome | ||||
This standard has been established for the purpose of informing applicants of the preparation, submittal, and review procedures for development within areas that have environmentally valuable habitat in conformance with Article 1, Division 1, Floodplain and
Hazard Area Regulations, Chapter 26, Tucson Code; Article VIII, Watercourse Amenities, Safety and Habitat (WASH), Chapter 29, Tucson Code; and Section 5.7, Environmental Resource Zone (ERZ), Unified Development Code (UDC), Chapter 23, all of the Tucson Code; so that proper and adequate information is presented in a consistent manner, thereby providing the basis for an efficient and timely review.
This standard is further to insure that the adopted policies of the Mayor and Council and adopted recommendations of the city’s
Advisory Committee are accurately reflected in the implementation of existing regulations.
The areas subject to regulation under this technical standard include the floodplain and floodway fringe areas as defined in Section 26-2, and the adjacent banks and associated riparian habitat as provided in Section 26-5.2(3) and (4), which are established as the “regulated areas”. If there is no encroachment within these regulated areas, the documentation requirements, development restrictions and mitigation requirements do not apply.
Where the regulated areas are based upon maps prepared for the TSMS Phase II
Master Plan, the Critical and Sensitive Wildlife Habitat Map, or similar maps prepared by Pima County, there is a presumption that riparian habitat that should be preserved has been documented on the property. Any development must therefore comply with this standard to establish the precise location of riparian habitat. It is, however, the actual documentation of the location of the habitat pursuant to this standard that will determine where the development may occur, not the maps.
If there is encroachment into the regulated areas, the standard requires that the riparian habitat be identified and delineated as the “protected riparian area”. This will include the submittal of an Environmental Resource Report that will document (1) the areas that contain riparian and wildlife habitat that is to be preserved and (2) those areas without such habitat. Development is permitted within the regulated areas that are outside the protected riparian areas. Development within the protected riparian area is limited as set forth in this standard.
It is the intent of this standard that the protected riparian area incorporate the Critical Riparian Habitat in ERZ watercourses, the Resource Areas in WASH watercourses, and riparian habitat within the undesignated regulatory floodplains so that there is a single process for review with consistent criteria for application.
This standard does not waive any applicable city regulations or codes.
This standard applies to all applications accepted for review after November 7, 2006. Exceptions to this applicability include:
A. This standard does not apply to single family residential lots with dwellings constructed in accordance with the building permits issued before November 7, 2006.
B. This standard does not apply in a manner that conflicts with a rezoning or special exception approved by the Mayor and Council after November 7, 2001.
C. This standard may apply to an exempt application at the request of the applicant.
The information required as part of a submittal under this standard will be shown graphically or provided as notes on a plan, as appropriate. The required information is in addition to the plan or plat requirements of the applicable process, such as, but not limited to, a plat, a development plan, a
plan, or a plot plan.
The regulated areas are listed below:
A. ERZ Watercourses
The regulated area for ERZ watercourses includes the 100-year floodplain for all watercourses. ERZ watercourses include:
1. Watercourses zoned as ERZ;
2. Watercourses that have been designated for preservation in the Tucson
Management Study and are delineated as proposed for ERZ designation or as under review for ERZ designation shall be considered as ERZ watercourses; or
3. The designated, proposed and under review watercourses are shown on the Hydrologic Data and Wash Information maps on the Tucson Department of Transportation internet web site.
B. WASH Watercourses
The regulated area for WASH watercourses includes channel and banks of a watercourse and the area within 50 feet of the top of the bank, or where there is no defined bank, 50 feet from the ten-year flood boundary. WASH watercourses include:
1. Watercourses designated by name in the Watercourse Amenities, Safety and Habitat regulations in Article VIII of Chapter 29.
2. Watercourses that have been designated for preservation in the Tucson
Management Study and delineated as proposed for WASH designation or as under review for WASH designation shall be considered as WASH designated watercourses.
3. The designated, proposed and under review watercourses are shown on the Hydrologic Data and Wash Information maps on the Tucson Department of Transportation internet web site.
4. The regulated area for watercourses under this technical standard 4-02.2.2.B.2 and 3 above shall not extend beyond the 100-year floodplain.
C. Regulatory Floodplain Watercourses
Within floodplains that are not designated as an ERZ or WASH watercourses in accordance with Sections 4-02.2.2.A or B above, the regulated area is the area within the 100-year floodplain for watercourses with flows of 100 cfs or more including, by not limited to, those areas which contain any of the following:
1. Hydroriparian, Mesoriparian, or Xeroriparian Types A, B or C habitats as delineated by Pima County as part of Article X of the Pima County Floodplain and
Hazard Ordinance.
2. Hydroriparian, Mesoriparian, or Xeroriparian High or Xeroriparian Intermediate Habitats as delineated in the TSMS Phase II
Master Plan.
3. Xeroriparian Low Habitats as delineated in the TSMS Phase II
Master Plan or Type D habitat as delineated by Pima County for connectivity between higher habitat classes, if low-volume, high-value habitats are present, including tabosa swales or similar habitats.
4. Unclassified or undocumented riparian habitat of equivalent value to the above criteria.
The protected riparian area is the area that has riparian habitat that is to be preserved. Except for watercourses designated by ordinance as subject to ERZ and WASH regulations, the protected riparian area shall not exceed the 100-year floodplain. protected riparian areas include areas that provide habitat structure, wildlife food and shelter, and that also aid in supporting wildlife connectivity,
control and help to improve
quality. Riparian habitat may include the vegetative resources, mapped areas and wildlife habitat and corridors listed below where such habitat is riparian in nature and function.
A. Vegetative Resources
Vegetative Resources are groups of three or more individual plants in close proximity to each other representing any of the plant species (and any combination of associated vegetative structure) listed below.
1. Mesoriparian plant species, including Arizona walnut, Fremont cottonwood, Goodding (black) willow, Arizona sycamore, Arizona ash.
2. Over-story vegetation consisting of closely spaced, perennial, woody (e.g., mesquite, foothill palo verde, Mexican palo verde, ironwood, netleaf hackberry), that are generally six feet or more in total height, and where the distance between canopy margins of individuals of the predominant over-story plant species is less than two times the height of the tallest individuals.
3. Understory vegetation consisting of closely spaced, perennial woody plants (e.g., catclaw and whitethorn acacia) that are generally six feet in total height, or less, and where the distance between canopy margins of individuals of the predominant understory plant species is generally less than two times the height of the tallest individuals, excluding nearly pure stands of understory vegetation consisting of the following perennial woody plants: burrow bush, creosote bush, desert broom, or triangle-leaf bursage.
4. Combinations of overstory and understory vegetation that together constitute valuable habitat, and tobasa swales.
B. Mapped Areas shown on the Critical and Sensitive Wildlife Habitat Maps which contain:
1. Major segments of desert riparian habitat extending from public preserves;
2. Major segments of desert riparian habitat not extending directly from a public preserve but containing a high density and diversity of plant and animal species;
3. Deciduous riparian woodlands;
4. Mesquite bosques; and,
5. Lakes, ponds, or wetlands.
C. Wildlife includes, but is not limited to, the wildlife and areas identified in the public draft or final City of Tucson Habitat Conservation Plan applicable to the regulated area.
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