ECOSOL TREE PIT
WATER SENSITIVE URBAN DESIGN & CONSTRUCTED WETLANDS
STREETSCAPE STORMWATER TREATMENT SYSTEM
Ecosol Tree Pits are mini rain gardens (also known as Tree Filter Boxes or Street Tree Wells) that comprise of a tree planted within an underground pre-cast concrete pit that generally consists of a combination of media layers that allows stormwater to slowly infiltrate from the surface down to underdrain pipes where the treated stormwater is then conveyed to a traditional stormwater drainage system.
Today Tree Pits are an integral part of a total treatment train approach and are incorporated into most street scape designs. As they are applied at a street scale to capture and treat stormwater runoff close to its source, they not only provide us with a compact, efficient stormwater treatment solution they also help to enhance streetscape aesthetics.
The Ecosol Tree Pit is a modern, fully self-contained stormwater treatment system that provides tertiary treatment of stormwater flows in one compact device at a street scape level.
The system has been designed to provide a robust and durable cost effective, aesthetically attractive kerb-side treatment system. The system is filled with porous filter media and planted with vegetation to remove pollutants from stormwater runoff using natural and physical processes.
In developing this innovative stormwater treatment system careful consideration has been given to durability, longevity, cost, and maintainability. Key commercial technical features include:
- low visual impact and energy footprint
- designed hydraulics with proven performance and longevity
- scalable, adaptable design and
- cost effective maintenance regime.
At Urban Asset Solutions we can site measure, fabricate, install and maintain your Tree Pit making the whole process seamless.
The Ecosol Tree Pit is designed as a fully self-contained stormwater treatment system for roadside applications. It is supplied to site complete with all internal drainage components factory installed and with the engineered soil media and grated access covers supplied loose.
| Ecosol TREE PIT TYPICAL DIMENSIONS | ||||
|---|---|---|---|---|
| Ecosol Product Code | Internal Pit Dimensions L x W x D (mm) | External Pit Dimensions L x W x D (mm) | Loading Classification | Weight (t) |
| Ecosol Tree | 1200 x 1200 x 1200 | 1650 x 1650 x 1650 | B | 4.0 |
| Ecosol Tree Pit Typical Dimensions - 2018 | ||||
The components and accessories supplied with the Ecosol Tree Pit, providing a complete system thereby reducing on site installation times.
| Ecosol TREE PIT COMPONENTS SPECIFICATION | |
|---|---|
| Item No. | |
| 1 | Kerb inlet penetration (typically standard BBC Tye E) 150 x 100 WSUD inlet |
| 2 | Roof water inlet penetration (typically 100mm PVC) |
| 3 | Drain clean-out riser pipe (100mm PVC screc cap) factory fitted |
| 4 | Underdrain layer pipes (slotted 100mm PVC) factory fitted |
| 5 | Drainage layer (150mm washed fine gravel) suplied in bag to site |
| 6 | Transition layer (100mm FAWB approved coarse washed sand) supplied in bag to site |
| 7 | Bio filtration layer (750mm FAWB approved sandy loam) supplied in bag to site |
| 8 | Gravel screening layer (50mm coarse 18m gravel) supplied in bag to site |
| 9 | Pedestrian access grate (loading class light duty) |
| 10 | Pre-cast concrete steel reinforced Tree Pit (ecternal dimensions 1.65L x 1.65W x 1.65D m) 40Mpa |
| Ecosol Tree Pit Components Specification - 2018 | |
General Notes:
- The products engineered media for the range of Ecosol Tree is supplied and installed separately.
- Installation and operation of the Ecosol Tree Pit is recommended once site conditions have stabilised.
- The under drain collection pipes, geo-fabric and ductile iron access covers are supplied factory fitted with the Ecosol Tree Pit.
- For optimal performance a temporary ponding depth of 300mm above the infiltration layer is recommended.
- Careful selection of the most appropriate vegetation is necessary to ensure optimal performance of your Tree Pit. Urban Asset Solutions can supply the system complete with appropriate plants ready for installation. Alternatively you can select your own, however we recommend you consult with your local council to determined preferred species or refer to the Adoption Guidelines for Stormwater Biofiltration Systems Table 15 List of known species” released July 2015 as part of the CRC for Water Sensitive Cities.
The typical infiltration rate of a biofilter is 150mm/hour (0.04L/s/m2) for established vegetated zones. Urban Asset Solutions can assist with the most appropriate design and sizing of your biofilter specific to your site requirements.
Treatable Flow Rate
Careful selection of the soil media and vegetation is necessary along with appropriate ponding depths and detention to ensure optimal performance of your Ecosol Tree Pit. As the system has a surface footprint of 1.44m2 an estimated infiltration rate of approximately 0.056L/s is likely with a 100mm ponding depth.
By-Pass Capacity & Headloss
The systems is designed to have a ponding depth of approximately 100mm and will by-pass flows exceeding the estimated infiltration rate downstream to the next available kerb inlet.
Suggested removal efficiencies for the Ecosol Biofilter are in accordance with the CRC for Water Sensitive Cities Adoption Guidelines for Stormwater Biofiltration System (July 2015).
| Ecosol TREE PIT CAPTURE EFFICIENCY PERFORMANCE SUMMARY | ||
|---|---|---|
| Pollutant | Removal efficiency | Details |
| Gross Pollutants (GP) | 98% | Particulate >200 micron |
| Suspended Solids (SS) | 95% | Particulate |
| Phosphorous (P) | 65% | Particulate |
| Nitrogen (N) | 50% | Particulate |
| Heavy Metals | 90% | Particulate |
| Total Petroleum Hydrocarbons (TPH) | 99% | In dry and wet weather flows |
| Ecosol Tree Pit Removal Efficiencies - 2018 | ||
Water Sensitive Urban Design (WSUD) assets require regular scheduled maintenance to ensure they remain healthy and perform as intended. It is important to regularly inspect the filter media to monitor sediment, gross pollutant and leaf litter accumulation. Additionally any weeds should be removed, plant health and detention zones monitored and periodic flushing out of the underdrain system is necessary to ensure the system continues to perform to its designed specification. The Ecosol Tree Pits simple design makes access for cleaning and maintenance easy using standard equipment.
The below table provides a general guide of key activities necessary to maintain your Tree pit system.
| Ecosol TREE PIT CHAMBER FUNCTIONS & CLEANING FREQUENCY | ||
|---|---|---|
| Item | Activity | Recommended Frequency |
| Mulch | Ensure you have adequate mulch cover to prevent scouring | Every 3 months or immediately after a storm event |
| Filter Media | Remove leaf litter and gross pollutants | Every 3 months or immediately after a storm event |
| Monitor ponding depths to ensure soil media is providing adequate infiltration rates | Every 3 months or immediately after a storm event | |
| If necessary remove excess sediment or replace the top layer of soild media and remulch | Every 3 months or immediately after a storm event | |
| Vegetation | Ensure plant life is healthy | Every 3 months or immediately after a storm event |
| Remove all weeds | Every 3 months or immediately after a storm event | |
| Water as necessary | Seasonal Activity | |
| Structural Components | Inspect all structural elements to ensure structural integrity | Annually |
| Flush underdrain pipe systems | Annually | |
| Ensure all inlets and outlets from the system are free of any debris | Annually | |
| Ecosol Tree Pit Functions of each Chamber and Cleaning Frequency - 2018 | ||