city of austin drainage criteria manual

City of Austin Drainage Criteria Manual⁚ A Comprehensive Guide

The City of Austin Drainage Criteria Manual (DCM) is a comprehensive guide for the design and management of drainage systems in Austin and Travis County. It covers topics such as storm runoff‚ street flow‚ inlets‚ storm drains‚ open channels‚ culverts‚ stormwater management‚ and drainage charge administration. The DCM is a critical tool for ensuring that development in the city is sustainable and protects the environment. The manual is updated regularly to reflect changes in regulations and best practices.

Introduction

The City of Austin Drainage Criteria Manual (DCM) is a comprehensive document that outlines the city’s policies and technical standards for stormwater management. It serves as a guide for developers‚ engineers‚ and other stakeholders involved in the design and construction of drainage systems within the city limits and its extraterritorial jurisdiction. The DCM aims to ensure the efficient and sustainable management of stormwater runoff‚ protect public health and safety‚ and preserve the natural environment. It establishes a framework for managing stormwater runoff‚ minimizing flooding risks‚ and mitigating the impacts of development on the city’s valuable water resources.

1.1. Purpose and Scope

The primary purpose of the City of Austin Drainage Criteria Manual is to establish a set of standardized principles and practices for the design and construction of drainage systems throughout the city and its surrounding areas. The manual’s scope encompasses various aspects of stormwater management‚ including storm runoff calculation methods‚ drainage system design considerations‚ and stormwater management strategies. It provides detailed guidelines for addressing street flow‚ inlets‚ storm drains‚ open channels‚ culverts‚ and stormwater management techniques‚ ensuring that all development projects within the city meet the necessary drainage criteria.

1.2. Applicability

The City of Austin Drainage Criteria Manual applies to all development projects within the city’s jurisdiction‚ including both public and private developments. This encompasses new construction‚ renovations‚ and infrastructure projects. The manual’s guidelines are essential for developers‚ engineers‚ and contractors involved in any project that impacts the city’s drainage system. It ensures that all development activities are conducted in a manner that minimizes potential adverse effects on the environment and promotes sustainable stormwater management practices. The manual also covers areas under the city’s extraterritorial jurisdiction‚ ensuring consistent drainage standards across a wider area.

Drainage Policy

The City of Austin’s Drainage Policy is rooted in the principles of sustainable development and environmental protection. The policy emphasizes the importance of managing stormwater runoff effectively‚ reducing the risk of flooding and erosion‚ and preserving the city’s natural water resources. This policy is a guiding document for all aspects of drainage design and management in Austin‚ influencing the development of infrastructure‚ regulations‚ and best practices. It aims to ensure that development activities are carried out in a way that minimizes their impact on the environment and the quality of life for residents. The policy also promotes the use of green infrastructure solutions‚ such as detention ponds and permeable pavements‚ to manage stormwater runoff in an environmentally friendly manner.

2.1. General Principles

The City of Austin’s Drainage Policy is built on a set of general principles that guide the design and management of drainage systems. These principles emphasize the importance of minimizing the impact of development on the natural environment and protecting public safety. They include the need to maintain natural drainage patterns‚ reduce stormwater runoff volumes‚ and enhance water quality. The policy also prioritizes the use of green infrastructure solutions‚ such as detention ponds and permeable pavements‚ to manage stormwater runoff in a sustainable and environmentally friendly manner. These principles are reflected in the detailed technical criteria and standards outlined in the Drainage Criteria Manual‚ ensuring that drainage systems are designed and constructed to meet the city’s goals for sustainable development and environmental protection.

2.2. Stormwater Runoff Management

The City of Austin’s Drainage Criteria Manual emphasizes a proactive approach to stormwater runoff management. This involves a shift from simply conveying runoff away from development sites to managing it in a way that minimizes its impacts on the environment. This includes utilizing a range of techniques to reduce the volume and velocity of runoff‚ such as detention ponds‚ retention basins‚ and green infrastructure elements. The manual also includes guidance on the design and implementation of water quality control measures to remove pollutants from stormwater runoff before it reaches our creeks and lakes. The City of Austin is committed to using stormwater as a resource rather than a waste product‚ and the Drainage Criteria Manual provides the framework for achieving this goal through innovative and sustainable stormwater management practices.

Determination of Storm Runoff

The City of Austin Drainage Criteria Manual (DCM) provides comprehensive guidance on how to determine the amount of stormwater runoff that will be generated from a development site. This involves considering factors such as the size and shape of the site‚ the type of land cover‚ and the intensity and duration of rainfall. The DCM outlines various methods for calculating runoff‚ including the Rational Method‚ the SCS Curve Number Method‚ and the TR-55 method. These methods allow engineers to estimate the peak flow rate and volume of runoff for different storm events‚ which is essential for designing drainage systems that can safely convey the runoff without causing flooding or erosion.

3.1; Rainfall Criteria

The City of Austin Drainage Criteria Manual (DCM) establishes specific rainfall criteria for designing drainage systems. It uses historical rainfall data to define the frequency and intensity of storms that should be considered in the design. The DCM specifies rainfall depths and durations for different return periods‚ such as the 2-year‚ 10-year‚ 25-year‚ and 100-year storms. These return periods represent the probability of a storm of a given magnitude occurring in a given year. The DCM also considers the spatial variability of rainfall within the city‚ recognizing that different areas experience different rainfall patterns. This information is crucial for ensuring that drainage systems are designed to handle the expected rainfall events and minimize the risk of flooding.

3.2. Runoff Calculation Methods

The City of Austin Drainage Criteria Manual (DCM) outlines various methods for calculating stormwater runoff‚ which is essential for designing effective drainage systems. These methods consider factors like rainfall intensity‚ duration‚ and the characteristics of the watershed‚ including its size‚ land cover‚ and soil type. The DCM emphasizes using scientifically sound and widely accepted techniques‚ such as the Rational Method‚ the SCS Curve Number Method‚ and the TR-55 method. These methods allow engineers to estimate the volume and rate of runoff generated from different types of developments‚ ensuring that drainage systems can adequately convey the anticipated water flow. The DCM also provides guidance on incorporating geographic information system (GIS) tools for runoff calculations‚ enabling more accurate and efficient assessments of drainage needs.

Drainage System Design

The City of Austin Drainage Criteria Manual (DCM) provides comprehensive guidelines for the design of drainage systems‚ ensuring the efficient collection‚ conveyance‚ and disposal of stormwater. The DCM emphasizes the importance of integrating drainage systems with the overall development plan‚ ensuring that streets‚ inlets‚ storm drains‚ open channels‚ and culverts are designed to handle the anticipated runoff volumes and flow rates. The manual outlines specific design criteria for each component‚ considering factors such as hydraulic capacity‚ slope‚ materials‚ and maintenance requirements. The DCM also encourages the use of innovative design approaches‚ such as green infrastructure and bioretention techniques‚ to manage stormwater in a sustainable and environmentally friendly manner.

4.1. Street Flow

The City of Austin Drainage Criteria Manual (DCM) addresses street flow design‚ ensuring that streets are designed to effectively convey stormwater runoff. The DCM emphasizes the importance of minimizing street flooding and erosion‚ while also considering the impact of street flow on adjacent properties and infrastructure. The manual provides detailed guidelines for street grading‚ curb and gutter design‚ and the placement of inlets and storm drains. These guidelines are based on hydraulic principles and take into account factors such as rainfall intensity‚ street width‚ and the surrounding topography. The DCM encourages the use of innovative design solutions‚ such as permeable pavements and bioswales‚ to manage street flow in a sustainable and environmentally friendly manner.

4.2. Inlets and Storm Drains

The City of Austin Drainage Criteria Manual (DCM) provides comprehensive guidelines for the design and installation of inlets and storm drains. The DCM emphasizes the importance of selecting appropriate inlet types‚ based on factors such as flow rate‚ debris accumulation‚ and the surrounding topography. The manual also addresses the design of storm drains‚ including pipe size‚ material‚ and slope. The DCM promotes the use of sustainable drainage practices‚ such as the use of green infrastructure and the incorporation of water quality treatment devices in inlets. The manual emphasizes the importance of proper maintenance and inspection of inlets and storm drains‚ to ensure their continued effectiveness and prevent blockages or failures.

4.3. Open Channels and Culverts

The City of Austin Drainage Criteria Manual (DCM) provides detailed specifications for the design and construction of open channels and culverts. The DCM emphasizes the importance of considering factors such as flow capacity‚ channel stability‚ and environmental impacts when designing these drainage structures. The manual outlines guidelines for selecting appropriate channel materials‚ shapes‚ and dimensions to ensure efficient and safe drainage. The DCM also addresses the need for proper maintenance of open channels and culverts to prevent debris accumulation‚ erosion‚ and vegetation growth that could compromise their functionality.

Stormwater Management

The City of Austin Drainage Criteria Manual (DCM) outlines a comprehensive approach to stormwater management‚ emphasizing sustainable practices that minimize the impact of development on the city’s watersheds. The DCM encourages the use of green infrastructure‚ such as rain gardens‚ bioswales‚ and permeable pavements‚ to manage stormwater runoff at the source. It also includes guidelines for the design and implementation of detention and retention ponds‚ which help to control runoff volume and reduce peak flow rates. The DCM emphasizes the importance of water quality control measures to protect the city’s streams‚ lakes‚ and aquifers from pollutants associated with stormwater runoff.

5.1. Detention and Retention

The City of Austin Drainage Criteria Manual (DCM) emphasizes the importance of detention and retention ponds in managing stormwater runoff. Detention ponds are designed to temporarily store stormwater runoff‚ allowing it to slowly infiltrate the ground or be released at a controlled rate. Retention ponds are designed to permanently store stormwater runoff‚ providing a valuable habitat for wildlife and enhancing water quality. The DCM provides detailed guidance on the design and construction of detention and retention ponds‚ including criteria for sizing‚ location‚ and landscaping. These structures play a crucial role in reducing peak flow rates‚ mitigating flooding‚ and improving water quality in Austin’s watersheds.

5.2. Green Infrastructure

The City of Austin Drainage Criteria Manual (DCM) promotes the use of green infrastructure as a key component of stormwater management. Green infrastructure refers to natural and nature-based solutions that mimic the natural processes of a watershed. Examples include rain gardens‚ bioswales‚ permeable pavements‚ and green roofs. These features help to reduce stormwater runoff‚ improve water quality‚ and enhance the aesthetic appeal of urban environments. The DCM provides guidance on the design and installation of green infrastructure‚ including requirements for sizing‚ materials‚ and maintenance. Green infrastructure is a sustainable and cost-effective approach to managing stormwater in Austin.

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