In this issue

 

Welcome

   - In this Edition

 

 

Helpful Tips

-  Pipe Plans

-  City Plan Mapping

-  Floodwise Property Reports

 

 

Frequently Asked Questions

-  Undercroft Clearance

 

 

Wrap Up

   - See you next month

 

 

Visit our website:

www.stormw.com.au 

 

 

Phone:

07 3398 4992

 

Welcome

Hello everyone and welcome to the February edition of “Keep Things Flowing”, the monthly newsletter presented by Storm Water Consulting.

In this month’s newsletter we provide you with some helpful stormwater and flooding related tips using Brisbane City Council data and we answer another frequently asked question about undercroft clearance.

 

Brisbane City Council Helpful Tips

Over the past few months we’ve shared some helpful stormwater and flooding related tips with our clients and we thought it would be beneficial for our readers if we were to share these with you too. We’ve picked three to start off with!

Pipe Plans

Brisbane City Council make stormwater pipe information available to the public through their online eBIMAP2 system. The eBIMAP2 system provides an integrated map of assets and properties. The eBIMAP2 system is available for access through a subscription based format. Subscriptions can be bought for a day, week, month or year long period. Council’s eBIMAP2 system can be accessed using the link provided below.  

eBIMAP2 Mapping

https://www.brisbane.qld.gov.au/planning-building/planning-guidelines-tools/online-tools/ebimap2-mapping-service

We subscribe to the daily service which costs $22.60. This allows us to print as many plans for as many jobs as needed (within a 24 hour period).

City Plan Mapping

Council’s City Plan mapping is an interactive mapping system that provides property information, zoning, overlays, aerial mapping and ground level information. City Plan mapping is available free of charge and can be accessed through the link provided below.

City Plan Mapping

http://cityplan2014maps.brisbane.qld.gov.au/CityPlan/

The City Plan mapping is a useful tool when determining whether a property is located in or adjacent to a Flood Planning Area. To illustrate the Flood Planning Areas simply search for a property address, open the “Overlays” tab on the left hand side of the page and expand the “Flood” category and select through the Brisbane River, Creek/waterway or Overland Flow categories.

Note, the Flood Planning Areas do not necessarily reflect the inundation expected during a flood event.

Floodwise Property Reports

If the property you searched for in the City Plan mapping (discussed above) is located within a Brisbane River or Creek/waterway Flood Planning Area, flood level information for the property is provided by the Council, free of charge. The flood level information is presented in Floodwise Property Reports, which can be accessed using the following link.

Floodwise Property Reports

https://www.brisbane.qld.gov.au/planning-building/planning-guidelines-tools/online-tools/floodwise-property-report

If your property is located within an Overland Flow Flood Planning Area, flood level information is not available for the property. A hydraulic engineer is required to determine the flood level affecting the property. We would be pleased to provide you with assistance in determining the overland flow flood levels. Please contact our office to speak to one of our engineers.  

 

Frequently Asked Question

Question

I plan to build a dwelling on my property. Using Council’s City Plan mapping I have identified that the location of the dwelling is within an overland flow path. Will I have to construct the dwelling on a suspended floor to allow the overland flow to flow underneath the dwelling? I need the undercroft height to be as short as possible due to building height restrictions.

Answer

It is important to remember that the Overland Flow Flood Planning Area shown on Council’s City Plan mapping is just a tool to indicate that there could be an overland flow issue on the property. There is no detailed hydraulic modelling supporting the extent of the Overland Flow Flood Planning Area. A hydraulic engineer would be required to determine if and where overland flow is located on the property.

Let’s assume we’ve completed an assessment of the overland flow and found that there is overland flow at the location of the proposed dwelling. For this example let’s also assume there is no other solution than to construct the dwelling on a suspended floor and allow the overland flow to pass underneath the dwelling. Brisbane City Council’s Flood Overlay Code requires structures with an undercroft area that experience overland flow depths up to 0.6m to provide 1.5m of undercroft clearance (distance between the ground level and the finished floor level). The purpose of the undercroft clearance requirement is to ensure debris in the overland flow path would not get caught on the underside of the structure and block the overland flow path. Blocking the overland flow path could cause flood level impacts to the subject site and neighbouring properties. In addressing the Flood Overlay Code, we have the ability to address a performance outcome solution and recommend lowering the undercroft clearance requirement. Supporting a lower undercroft clearance height is dependant upon the flooding characteristics and site constraints. An example of supporting a lower undercroft height could be if the depth of overland flow is 0.2m and the velocity is very slow. An undercroft height of 1.5m could be excessive given the flow conditions and other site constraints. If you would like assistance with determining a suitable undercroft clearance please contact our office. I link to the Flood Overlay Code is presented below.

Flood Overlay Code

http://eplan.brisbane.qld.gov.au/CP/FloodOC

 

Wrap Up

We hope you enjoyed this edition of Keep Things Flowing. Feedback on articles presented is always welcomed and for further information on any of the articles presented please don’t hesitate to contact our office.

As always, Keep Things Flowing!

The Storm Team

 

 

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