Hilltops Council (Council) commissioned the Floodplain Risk Management Study and Plan for the township of Boorowa. The overall objectives of the Floodplain Risk Management Study (FRMS) were to assess the impacts of flooding, review existing Council policies as they relate to development of land in flood liable areas, consider options for the management of flood affected land and to develop a Floodplain Risk Management Plan (FRMP) which: i) Proposes modifications to existing Council policies to ensure that the development of flood affected land is undertaken so as to be compatible with the flood hazard and risk. ii) Proposes Flood Planning Levels for the various land uses in the floodplain. iii) Sets out the recommended program of works and measures aimed at reducing over time, the social, environmental and economic impacts of flooding. iv) Provides a program for implementation of the proposed works and measures. The FRMS focuses on Main Stream Flooding from the Boorowa River, Ryans Creek and Ryans Tributary, as well as two major un-named tributaries, Minor Tributary Flooding caused by high flows in the minor un-named tributaries which drain to the aforementioned watercourses, and Major Overland Flow areas which occur in the urbanised parts of Boorowa and its immediate surrounds.

Objectives The objective of this Study is to define the nature of the existing flood behaviour in the Burradoo BU2 catchment. To achieve the objective, the following tasks were undertaken:,

Map notes:North Esk & Tamar Flood Water Surface ProfilesFor use in Planning GeneralThese maps indicate North Esk derived flood levels from the Black Bridge to Corra Linn. The maximum flood levels below Hobblers Bridge and in the Tamar are determined by South Esk discharges into the Tamar which provide higher elevations than the North Esk discharges for the same Average Recurrence Interval (ARI).This map is primarily intended for use in planning to that end it includes:A 100 year ARI profile with current sea level conditionsA 100 year ARI profile with 800mm rise in sea levelA 200 year ARI profileDischargesHydro Consulting was commissioned to review the South Esk hydrology while the North Esk hydrology was derived by the University of New South Wales Water Research laboratory. The Table 1 indicates the results of latter study used in the construction of this map.Flood Return Period in Years ARINorth Esk Flood Discharges (UNSW WRL 2006)South Esk Discharges (Hydro Consulting 2008)1034514302041918105052623301006142910200710(Monte Carlo Range)1850 3430 39905008514630Table 1The adopted tail-water level used in the North Esk analysis for this map was 2.1 m AHD at the junction with the Tamar for all discharges. This represents the highest astronomical tide at Launceston with average atmospheric pressure and neutral wind conditions. The North Esk model was successfully calibrated to the flood which occurred on 30thAugust 2005 which peaked at 470 cumecs and the flood which occurred on 21stJune 2011 at 251 cumecs.

Volume 1 Report This flood study has been undertaken to determine the flood behaviour in the catchment due to local storm runoff for the 0.5% Annual Exceedance Probability (AEP), 1% AEP, 2% AEP, 5% AEP, 10% AEP, 20% AEP, 50% AEP and 100% AEP flood events and the Probable Maximum Flood (PMF). In accordance with its objectives, the study has determined the nature and extent of flooding through the estimation of design flood flows, levels and velocities. Flood impacts due to storm events in the Brisbane Water estuary are detailed in the Brisbane Water Foreshore Flood Study (2009). In undertaking the flood study, a hydrologic-hydraulic computer model of the major channels and floodplain within the catchment was established and verified against historical flood event observations. The hydraulic model was then used with design rainfall conditions to simulate design flood behaviour in the catchment. The study has defined Provisional Flood Hazard and Hydraulic Categories for the flood affected areas. The objective of this Study is to define the nature of the existing flood behaviour due to local runoff only in the Davistown catchment. To achieve the objectives, the following tasks were undertaken:,

Map notes:North Esk & Tamar Flood Water Surface ProfilesFor use in Planning GeneralThese maps indicate North Esk derived flood levels from the Black Bridge to Corra Linn. The maximum flood levels below Hobblers Bridge and in the Tamar are determined by South Esk discharges into the Tamar which provide higher elevations than the North Esk discharges for the same Average Recurrence Interval (ARI).This map is primarily intended for use in planning to that end it includes:A 100 year ARI profile with current sea level conditionsA 100 year ARI profile with 800mm rise in sea levelA 200 year ARI profileDischargesHydro Consulting was commissioned to review the South Esk hydrology while the North Esk hydrology was derived by the University of New South Wales Water Research laboratory. The Table 1 indicates the results of latter study used in the construction of this map.Flood Return Period in Years ARINorth Esk Flood Discharges (UNSW WRL 2006)South Esk Discharges (Hydro Consulting 2008)1034514302041918105052623301006142910200710(Monte Carlo Range)1850 3430 39905008514630Table 1The adopted tail-water level used in the North Esk analysis for this map was 2.1 m AHD at the junction with the Tamar for all discharges. This represents the highest astronomical tide at Launceston with average atmospheric pressure and neutral wind conditions. The North Esk model was successfully calibrated to the flood which occurred on 30thAugust 2005 which peaked at 470 cumecs and the flood which occurred on 21stJune 2011 at 251 cumecs.

Map notes:North Esk & Tamar Flood Water Surface ProfilesFor use in Planning GeneralThese maps indicate North Esk derived flood levels from the Black Bridge to Corra Linn. The maximum flood levels below Hobblers Bridge and in the Tamar are determined by South Esk discharges into the Tamar which provide higher elevations than the North Esk discharges for the same Average Recurrence Interval (ARI).This map is primarily intended for use in planning to that end it includes:A 100 year ARI profile with current sea level conditionsA 100 year ARI profile with 800mm rise in sea levelA 200 year ARI profileDischargesHydro Consulting was commissioned to review the South Esk hydrology while the North Esk hydrology was derived by the University of New South Wales Water Research laboratory. The Table 1 indicates the results of latter study used in the construction of this map.Flood Return Period in Years ARINorth Esk Flood Discharges (UNSW WRL 2006)South Esk Discharges (Hydro Consulting 2008)1034514302041918105052623301006142910200710(Monte Carlo Range)1850 3430 39905008514630Table 1The adopted tail-water level used in the North Esk analysis for this map was 2.1 m AHD at the junction with the Tamar for all discharges. This represents the highest astronomical tide at Launceston with average atmospheric pressure and neutral wind conditions. The North Esk model was successfully calibrated to the flood which occurred on 30thAugust 2005 which peaked at 470 cumecs and the flood which occurred on 21stJune 2011 at 251 cumecs.

Map notes:North Esk & Tamar Flood Water Surface ProfilesFor use in Planning GeneralThese maps indicate North Esk derived flood levels from the Black Bridge to Corra Linn. The maximum flood levels below Hobblers Bridge and in the Tamar are determined by South Esk discharges into the Tamar which provide higher elevations than the North Esk discharges for the same Average Recurrence Interval (ARI).This map is primarily intended for use in planning to that end it includes:A 100 year ARI profile with current sea level conditionsA 100 year ARI profile with 800mm rise in sea levelA 200 year ARI profileDischargesHydro Consulting was commissioned to review the South Esk hydrology while the North Esk hydrology was derived by the University of New South Wales Water Research laboratory. The Table 1 indicates the results of latter study used in the construction of this map.Flood Return Period in Years ARINorth Esk Flood Discharges (UNSW WRL 2006)South Esk Discharges (Hydro Consulting 2008)1034514302041918105052623301006142910200710(Monte Carlo Range)1850 3430 39905008514630Table 1The adopted tail-water level used in the North Esk analysis for this map was 2.1 m AHD at the junction with the Tamar for all discharges. This represents the highest astronomical tide at Launceston with average atmospheric pressure and neutral wind conditions. The North Esk model was successfully calibrated to the flood which occurred on 30thAugust 2005 which peaked at 470 cumecs and the flood which occurred on 21stJune 2011 at 251 cumecs.

The study was commissioned by Bayside Council, with the assistance of the NSW Government Office of Environment and Heritage (OEH). Additional information has been provided by Sydney Water Corporation (SWC). The Flood Study comprises the development of computational hydrologic and hydraulic models that define design flood behaviour for the 20% AEP (0.2 EY), 10% AEP, 5% AEP, 1% AEP and 0.5% Annual Exceedance Probability (AEP) design storms and the Probable Maximum Flood (PMF) in the Bardwell Creek and Wolli Creek catchments.

Map notes:North Esk & Tamar Flood Water Surface ProfilesFor use in Planning GeneralThese maps indicate North Esk derived flood levels from the Black Bridge to Corra Linn. The maximum flood levels below Hobblers Bridge and in the Tamar are determined by South Esk discharges into the Tamar which provide higher elevations than the North Esk discharges for the same Average Recurrence Interval (ARI).This map is primarily intended for use in planning to that end it includes:A 100 year ARI profile with current sea level conditionsA 100 year ARI profile with 800mm rise in sea levelA 200 year ARI profileDischargesHydro Consulting was commissioned to review the South Esk hydrology while the North Esk hydrology was derived by the University of New South Wales Water Research laboratory. The Table 1 indicates the results of latter study used in the construction of this map.Flood Return Period in Years ARINorth Esk Flood Discharges (UNSW WRL 2006)South Esk Discharges (Hydro Consulting 2008)1034514302041918105052623301006142910200710(Monte Carlo Range)1850 3430 39905008514630Table 1The adopted tail-water level used in the North Esk analysis for this map was 2.1 m AHD at the junction with the Tamar for all discharges. This represents the highest astronomical tide at Launceston with average atmospheric pressure and neutral wind conditions. The North Esk model was successfully calibrated to the flood which occurred on 30thAugust 2005 which peaked at 470 cumecs and the flood which occurred on 21stJune 2011 at 251 cumecs.

The overall objective of this study is to develop a Floodplain Risk Management Study where management issues are assessed, management options are investigated and recommendations are made. Thereafter a Floodplain Risk Management Plan detailing how flood prone land within the study area is to be managed can be completed. The objectives of the Flood Risk Management Study are to:,