Storm Drain Baffle for Sediment Retention

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Solution Overview

Problem

Existing stormwater sumps fail to retain sediments effectively under high flow conditions, allowing sediment to be washed out and travel into lakes or rivers.

Innovation Solution

A flow-path baffle system is introduced into stormwater sumps, which disperses the high flow velocity of incoming water, reducing the concentration of flow energy and preventing scour and washout by distributing the inflow jet laterally and dissipating energy, thereby reducing sediment mobilization and removal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a traditional stormwater sump is used without baffles, then the structure is simple and maintenance is easier, but sediment retention is poor under high flow conditions

Engineering Contradiction:

Improvesediment retentionVSAvoidsump structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The sump is segmented into distinct zones using baffles - an inlet zone where high-velocity flow is dissipated, a sedimentation zone where particles settle, and an outlet zone. This segmentation allows each zone to perform its specific function, improving overall sediment retention while maintaining structural simplicity

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Baffles serve as intermediary structures between the inlet and outlet, mediating the flow transition. They dissipate kinetic energy from incoming flow and redirect water through a controlled path that promotes sedimentation, thereby improving retention without requiring complete redesign of the sump

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the sump allows free flow of stormwater, then the system is simpler and flow capacity is higher, but sediment washout increases under high flow conditions

Engineering Contradiction:

Improvesediment retentionVSAvoidflow capacity

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

Different regions of the sump are given different flow resistance characteristics. The inlet area near baffles has higher local resistance to dissipate energy, while the outlet area maintains lower resistance for efficient discharge. This local differentiation allows the system to retain sediment while preserving overall flow capacity

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The baffles apply partial resistance to the flow - enough to dissipate kinetic energy and promote sedimentation, but not so much as to significantly reduce flow capacity. The design achieves sufficient sediment retention with minimal impact on productivity by applying just the right amount of flow control

Inventive Principle:

Principle #16Partial or excessive action

3Reliability

If high flow velocity is maintained through the sump, then flow efficiency is higher, but sediment scour and washout increase

Engineering Contradiction:

Improvesediment retentionVSAvoidflow velocity

Core Design Contradiction:

ReliabilityVSSpeed

Solution Approach 1:

The flow velocity through the sump varies periodically - high velocity during inlet flow to maintain flush capacity, then reduced velocity in the sedimentation zone to allow particle settling. This periodic velocity variation enables the system to handle high flows while still achieving effective sediment retention

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The flow velocity parameter is changed from high (at inlet) to low (in sedimentation zone) through the use of baffles. This parameter transformation allows the system to maintain high flow efficiency during water conveyance while creating low-velocity conditions necessary for sediment settlement and retention

Inventive Principle:

Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The baffle system effectively reduces sediment washout and scour, improving sediment retention within the sump, requiring less frequent maintenance and minimizing sediment entry into water bodies.

Implementation Method 1

The baffle distributes the high flow velocity of at least one inlet jet across the baffle. The baffle provides head loss to reduce the concentration of flow energy in an inlet flow.

Methodology Applied

Scientific EffectTurbulence: Turbulence

Implementation Method 2

The baffle provides head loss to reduce the concentration of flow energy in an inlet flow

Methodology Applied

Scientific EffectHead loss: Pressure Drop

Data Source

PatentUS8715507B2Storm drain baffle to decrease sediment washout

Publication Date: 2014.05.06 UPSTREAM TECH

AI summary

Some examples includes a flow-through stormwater sump having a bottom and defining an inlet opening, an outlet opening and a top access opening, an inlet conduit coupled to the flow-through stormwater sump at the inlet opening, an outlet conduit coupled to the flow-through stormwater sump at the outlet opening and a flow-path baffle disposed in the stormwater sump, the flow-path baffle being substantially planar and defining a plurality of openings, the flow-path baffle oriented such that a centerline of the inlet conduit intersects a major plane of the baffle at a point and a centerline of the outlet conduit intersects the major plane at a further point, the flow-path baffle disposed in the stormwater sump in a direct impingement inlet flow-path of the inlet conduit and a direct impingement outlet back-flow-path of the outlet conduit.