Mudgee & Gulgong Stormwater Management Plan

BACKGROUND

The NSW Environmental Protection Authority (EPA) issued a notice under Section 12 of the Protection of the Environment Administration Act 1991 to all NSW councils early in 1998, requiring each council to develop an Urban Stormwater Management Plan. In response, the then Mudgee Shire Council commenced plan preparation in accordance with the Stormwater Management Plan (SMP) Guidelines (Managing Urban Stormwater Council Handbook, 1997) prepared by the EPA. This work was completed in 2001. You can download full details of the work undertaken below.


A number of the actions identified in the plan have been implemented including installation of Stormwater Quality Improvement Devices (SQIDs) at Mudgee and Gulgong. Significant work has also been undertaken on identification of salinity issues.

THE AIM OF THE STORMWATER MANAGEMENT PLAN

The Urban Stormwater Management Plan aims at addressing stormwater management problems within the catchment area, particularly water quality issues. The purpose of the Plan is to identify stormwater issues and achieve an overall improvement in the management of the stormwater system by recommending an action plan to the Council for implementing a stormwater improvement strategy.

FRAMEWORK AND SCOPE OF THE SMP

Managing stormwater is a continuous improvement process. The strategic focus is on developing, continually improving and implementing actions for encouraging the protection of stormwater environment. The Plan:

  • Describes the catchment
  • Identifies existing catchment conditions
  • Establishes the values of the catchment
  • States appropriate management objectives
  • Identifies management issues and causes
  • Evaluate potential management options
  • Contains Plan implementation strategies
  • Presents a performance monitoring program
  • Describes a mechanism on the implementation of the Plan

This Plan is focused on the urban area of the catchment.

COMMUNITY CONSULTATION AND COLLECTING EXISTING DATA

Critical to the Plan is the identification of stormwater values, objectives and issues in order to develop practical stormwater management options. To assist this process, community members and Government agency representatives were consulted on a number of occasions. This included a workshop session, which was held for the study area.

This document has been prepared from the many useful comments provided to the facilitators by these stakeholders during preliminary conversations and at the workshop session. This document thus benefits from the extensive local knowledge of the stakeholders who contributed.

STORMWATER CATCHMENT VALUES

Stormwater values were developed during one-to-one-stakeholder consultations.  These values were incorporated into the stakeholder briefing document.

The community considered good water quality to be most important and protection of community health and safety ranked second (see below).

Value Score
Good water quality 285
Protection of community health/safety 205
Protection of habitats 160
Community involvement/awareness 145
Protection of properties from localised flooding 95
Recreational Value 78
Weed/exotic species control 67
Aesthetics of the catchment 65

The ranking of the values will enable the Council to establish an ‘order of priority’ when considering management options for the Stormwater Management Plan. This process is ongoing and values will change over time. Therefore the process of developing and implementing a Stormwater Management Plan needs to be feasible and dynamic.

THE DEVELOPMENT OF STORMWATER MANAGEMENT OBJECTIVES

Objectives can be defined as those things we seek to achieve in terms of catchment protection and stormwater management.  Objectives were developed to help Council achieve their values. Considerable time was spent reviewing objectives at the workshop session. These are listed below as a summarised version including the changes made after the workshops. A detailed version can be found in section 5.0 of the report. The objectives were linked to the key values by the facilitators. This assisted to demonstrate how each objective will help to address stormwater values (Table 5.1).

Objective Score
Improve water quality 640
Optimal infrastructure, management & design 605
Protection of community health and safety 585
Improve community awareness 560
Minimise erosion 495
Protection of aquatic and terrestrial habitats 372
Minimise localised flooding from stormwater 300
Minimise impacts of salinity 240

These were broken down into short term objectives, which provide means to achieve stormwater values in the short term and to support longer-term objectives. These may also be called sub-objectives and play an important part in the initial stage of stormwater management in terms of working towards long term objectives. Over time, the short term objectives will be achieved and will be replaced by other objectives as the need arises. 

STORMWATER MANAGEMENT ISSUES

From consultations with stakeholders and field observations, a number of stormwater issues within Mudgee and Gulgong were identified.

Stormwater issues were not ranked during the workshop however; the ranking methodology was discussed and accepted by the stakeholders. The issues were later ranked by the facilitators as listed below. For example Insufficient community awareness and Decreased Water Quality were ranked as most critical in terms of their impact on values such as water quality and aquatic habitats. A detailed list of these issues and the procedure of the ranking assessment can be found in Section 6.0.

Issue Score
Insufficient community awareness  1,812
Decreased water quality 1,597
Infrastructure/maintenance issues 1,490
Salinity 1,440
Erosion 1,055
Planning issues 905
Localised flooding from stormwater 885
Impact on Community health & safety 585
Impact on aquatic & terrestrial habitats 372

The ranking of these issues is beneficial for the Council to establish a relative benefit when considering stormwater options.

STORMWATER MANAGEMENT OPTIONS

From the stormwater issues and objectives, a list of preferred options was developed by the facilitators, which are listed in Section 7 of this Plan. These options were further assessed in terms of efficiency in meeting the stormwater objectives and addressing key issues. This involved a cost-benefit analysis and evaluation of each option, taking into consideration the likely impact of the options on residents and the likely capital and operating costs. The Stormwater Management Plan should be flexible in terms of the implementation strategies as environmental conditions may change over time and the Plan is designed as an ongoing, dynamic document.

Also refer to section 9 in the attached report, which details future directions in terms of stormwater management to Council.

STORMWATER IMPLEMENTATION STRATEGIES

This component of the SMP outlines proposed expenditures over a five year period. The strategy contains an action plan, which was derived from the management options described above and includes a budget, responsibility and timeframe. The implementation strategy also provides for evaluation and monitoring of the success of the Plan. The following table shows some of the outcomes of the cost/benefit analysis of options in the form of an action plan. Refer to Section 8.0 of this Plan for further detail.

 

Option Refer Table 7.1 ACTIONS ESTIMATED $ COST Capital Operating TIMEFRAME COMMENTS

Actions to be implemented by Council

COUNCIL ACTIONS

1 and 15

Integrated Community Education Program

$10,000-$20,000

$5,000 p.a.

2001/2002

Includes options ranked 1, 2 & 3 from Table 7.4

24

Develop a Salinity Management Plan

$10,000 - $15,000

$5,000 p.a

2001/2002

Managing the salinity problem in Mudgee is beyond the scope of a Stormwater Management Plan.

14

Investigate safety risks of open stormwater channels and culverts and restrict access if necessary

$5,000-$10,000

<$5,000p.a

2001/2002

 

12 and 7

Continue with riparian weed eradication and revegetation programs along the Cudgegong River and Redbank Creek

 

$5,000 - $10,000p.a

2001/2002

Continuation and expansion of a willow removal program already implemented by Council

5, 10 and 28

Council to develop and implement an erosion and sediment control plan

$5,000 - $10,000

$5,000 p.a.

2002/2003

 

29

Environmental/

Stormwater Training for Council Personnel

$10,000 -$15,000

<$5,000p.a

2002/2003

Integrating erosion & sediment control, chemical use, grounds watering

9 and 16

Enforce Erosion and Sediment Control on New Developments/

Construction Sites

<$5,000

$10,000 - $15,000p.a

2002/2003

By implementing fines for non-compliance, this action could become partly self-funding

6

Develop a trade waste policy and management system to regulate discharges and pollution from industrial and commercial sites.

$5,000 - $10,000

$10,000 - $15,000

2003/2004

By implementing trade waste charges, this action could become primarily self funding.

25

Review fertiliser and water use on Council’s grounds

$5,000

<$5,000

2003/2004

 

8,22 and 26

Ongoing maintenance of parks and gardens to use low maintenance native species

$20,000

 

2003/2004

Will reduce maintenance requirements, leading to reduced impacts from pesticides, fertilisers and over-watering

Actions that Council could implement if funding is available

COUNCIL ACTIONS

2, 27 and 28

Install CDS Unit downstream of commercial area prior to outlet in Lawson Park and in Mudgee Catchment C (Perry St)

$150,000

$10,000

2001/2002

 

3

Convert showground detention basin to a wet retention basin/wetland

$50,000

$10,000

2002/2003

This action will address numerous issues. Flood relief/detention will still occur, along with stormwater treatment. Planting of native wetland plant species will provide habitat.