Highlighted below: 2 of 2 extracted standards. Sections and highlights carry their own anchors.
APPENDIX 7-B#
WATER EFFICIENT LANDSCAPE DESIGN BUDGET CALCULATOR²#
Town of Avon requires proposed landscape designs to not exceed 7.5 gallons of water per square foot of area per season* (Gal/Sf/Season) allocation.§
The Water Efficient Landscape Design Budget Calculation is rooted in the formula:
Total Landscape Area / Water Needed to Support Landscaping.
In order to determine the Water Needed to Support Landscaping, all areas within any landscaping plans are assigned one of the following Hydrozone Water Use Categories:
- No Water
- Very Low
- Low
- Medium
- High
- Cool Season / Turf Grass
- Water Feature
Each Hydrozone Category represents an estimated Water Allocation needed to support its flora (See Table 1:1). Very Low, Low, Medium, and High Hydrozone categories also contain the potential to be Drip Irrigated or Spray Irrigated (Drip being less water-intensive than Spray).
Table 1:1 - Water Allocation per 1000 sq ft per season by Hydrozone Type#
| Hydrozone Water Use Category | Water Allocation for DRIP Irrigation (gallons) per 1000 sq ft | Water Allocation for SPRAY Irrigation (gallons) per 1000 sq ft |
|---|---|---|
| No Water | 0 | — |
| Very Low | 35 | 42 |
| Low | 2,900 | 3,500 |
| Medium | 7,600 | 9,150 |
| High | 10,500 | 12,500 |
| Cool Season / Turf Grass | — | 15,000 |
| Water Feature | — | 15,000 |
| Water Use Subtotal (gallons per season) | |
|---|---|
| Water Use Total (gallons per season) | |
| Total Irrigated Area (sq. ft) | |
| Total Project Area (sq. ft) | |
| Gal/Sf/Season |
The calculation requires the replacement of these numbers with the square footages of the hydrozones being proposed. Please see calculation examples for clarification.
*Season can be approximated as the period of time between the average date of the last killing frost in the spring to the average date of the first killing frost in the fall.
WATER EFFICIENT LANDSCAPE DESIGN BUDGET CALCULATION EXAMPLES#
Using these inputs relative to the size of each hydrozone in a single landscape plan, a person can assess the estimated water use for the entire landscaping plan. The following scenarios showcase the variety of landscaping plans possible, their estimated water use, and potential for approval under the 7.5 gallon per sf. per season limit.
Scenario One: A landscape plan that is equally split between areas that require no water, and turf grass areas:#
Scenario 1: Half Turf Grass#
| Hydrozone Water Use Category | Drip Irrigated Area (sq. ft) | Spray Irrigated Area (sq. ft) |
|---|---|---|
| No Water | 1500 | — |
| Very Low | 0 | 0 |
| Low | 0 | 0 |
| Medium | 0 | 0 |
| High | 0 | 0 |
| Cool Season / Turf Grass | — | 1500 |
| Water Feature | 0 | — |
| Water Use Subtotal (gallons per season) | 0 | 22,500 |
|---|---|---|
| Water Use Total (gallons per season) | 22,500 | |
| Total Irrigated Area (sq. ft) | 1500 | |
| Total Project Area (sq. ft) | 3000 | |
| Gal/Sf/Season | 7.5 |
Takeaways:
- This plan's water budget is exactly the maximum potential water allocated.
- Any landscaping plan that exceeds 50% turf grass will likely not be approved.§
Scenario Two: A drip-irrigated landscape plan that is equally split between Low, Medium, and High:#
Scenario 2: Low / Med / High Mix - DRIP#
| Hydrozone Water Use Category | Drip Irrigated Area (sq. ft) | Spray Irrigated Area (sq. ft) |
|---|---|---|
| No Water | 0 | — |
| Very Low | 0 | 0 |
| Low | 1000 | 0 |
| Medium | 1000 | 0 |
| High | 1000 | 0 |
| Cool Season / Turf Grass | — | 0 |
| Water Feature | 0 | — |
(Table continues below)
| Water Use Subtotal (gallons per season) | |
|---|---|
| Water Use Total (gallons per season) | |
| Total Irrigated Area (sq. ft) | |
| Total Project Area (sq. ft) | |
| Gal/Sf/Season |
(The calculation values for Scenario Two are to be completed using the water allocation figures from Table 1:1.)
Scenario Three: Low / High Mix - DRIP#
| Hydrozone Water Use Category | Drip Irrigated Area (sq. ft) | Spray Irrigated Area (sq. ft) |
|---|---|---|
| No Water | 0 | |
| Very Low | 0 | 0 |
| Low | 1500 | 0 |
| Medium | 0 | 0 |
| High | 1500 | 0 |
| Cool Season / Turf Grass | 0 | |
| Water Feature | 0 |
| Water Use Subtotal (gallons per season) | 20100 | 0 |
|---|---|---|
| Water Use Total (gallons per season) | 20100 | |
| Total Irrigated Area (sq. ft) | 3000 | |
| Total Project Area (sq. ft) | 3000 | |
| Gal/Sf/Season | 6.7 |
Takeaways:
- This plan's water budget is below the maximum potential water allocated.
- Scenario Three is less water-intensive than Scenario Two.
- A medium water hydrozone does not represent the median between the low and high hydrozones.
Scenario Four: Low / High Mix Spray#
| Hydrozone Water Use Category | Drip Irrigated Area (sq. ft) | Spray Irrigated Area (sq. ft) |
|---|---|---|
| No Water | 0 | |
| Very Low | 0 | 0 |
| Low | 0 | 1500 |
| Medium | 0 | 0 |
| High | 0 | 1500 |
| Cool Season / Turf Grass | 0 | |
| Water Feature | 0 |
| Water Use Subtotal (gallons per season) | 0 | 24000 |
|---|---|---|
| Water Use Total (gallons per season) | 24000 | |
| Total Irrigated Area (sq. ft) | 3000 | |
| Total Project Area (sq. ft) | 3000 | |
| Gal/Sf/Season | 8 |
Takeaways:
- This plan's water budget is above the maximum potential water allocated.
- Scenario Four is more water-intensive than Scenario Three, despite the hydrozone area sizes remaining the same in both.
- Spray irrigation is more water-intensive than drip irrigation, and could be the difference between approval / denial of a landscaping plan.
Scenario Five: Very Low / Low / Turf Mix#
| Hydrozone Water Use Category | Drip Irrigated Area (sq. ft) | Spray Irrigated Area (sq. ft) |
|---|---|---|
| No Water | 0 | |
| Very Low | 1000 | 0 |
| Low | 1000 | 0 |
| Medium | 0 | 0 |
| High | 0 | 0 |
| Cool Season / Turf Grass | 1000 | |
| Water Feature | 0 |
| Water Use Subtotal (gallons per season) | 2935 | 15000 |
|---|---|---|
| Water Use Total (gallons per season) | 17935 | |
| Total Irrigated Area (sq. ft) | 3000 | |
| Total Project Area (sq. ft) | 3000 | |
| Gal/Sf/Season | 6.0 |
Takeaways:
- Very Low and Low hydrozones can be adequate off-sets for turf grass area.
Scenario Six: Mix All#
| Hydrozone Water Use Category | Drip Irrigated Area (sq. ft) | Spray Irrigated Area (sq. ft) |
|---|---|---|
| No Water | 1000 | |
| Very Low | 1000 | 0 |
| Low | 1000 | 0 |
| Medium | 0 | 1000 |
| High | 0 | 1000 |
| Cool Season / Turf Grass | 1000 | |
| Water Feature | 500 |
| Water Use Subtotal (gallons per season) | 2935 | 44150 |
|---|---|---|
| Water Use Total (gallons per season) | 47085 | |
| Total Irrigated Area (sq. ft) | 5500 | |
| Total Project Area (sq. ft) | 6500 | |
| Gal/Sf/Season | 7.2 |
Takeaways:
- Equally mixed hydrozones have the potential for approval, even when water-intensive water features are included.
- A 1,000 sq ft water feature would exceed the 7.5-gallon allocation.
Footnotes:
(2)
Editor's note—Ord. 23-01, § 3, adopted February 28, 2023, added provisions for Appendix 7-B in its entirety, to read as herein set out.