Guidelines for Evaluating and Selecting Modifications to Existing Roadway Drainage Infrastructure to Improve Water Quality in Ultra-Urban Areas (2012) / Chapter Skim
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Pages 94-103
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94 Post-construction activities include BMP operation and maintenance, and BMP testing and monitoring. Maintenance is essential for design-level performance.
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95 • Groundwater: Shallow groundwater can affect the siting and capacity of infiltration BMPs, and groundwater flows into surface and underground BMPs may diminish the treatment effectiveness, cause excessive bypass, or require additional flow control and pumping. Maintenance activities due to high groundwater may include temporary or permanent pumping, more frequent routine and vegetation maintenance, and structural repairs or modifications.
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96 necessitate expensive lane closures and traffic-control procedures, and prompt safety concerns. • Uncommon requirements: Underground proprietary BMPs are more difficult to inspect and maintain than surface BMPs.
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97 burying pipes, increasing pipe slopes, and selection of salt-tolerant vegetation. Caraco and Claytor (1997)
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98 7.4 Maintenance Practices To support initial development and evaluation of retrofit options, Table 7.1 shows general maintenance practices and maintenance indicators by retrofit categories. Example maintenance practices are illustrated in Figure 7.2.
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(continued on next page) Maintenance Objective Frequency and Maintenance Indications Typical Maintenance Activitie s Comments C a t c h B a s i n R e t r o f i t G S R D R e t r o f i t s H y d r o d y n a m i c S y s t e m s O i l W a t e r S e p a r a t o r s A b o v e g r o u n d D e t e n t i o n U n d e r g r o u n d D e t e n t i o n M e d i a F i l t r a t i o n V e g e t a t e d F i l t r a t i o n I n f i l t r a t i o n F a c i l i t i e s P o r o u s P a v e m e n t s Site inspection • As scheduled per DOT or manufacturer guidance • Following major storms • As needed to address emergency, safety, and maintenance issues • Measure accumulated sediment, debris, and floatables and oil accumulation in sumps, forebays, basins, and vaults by visual inspection, with calibrated dipsticks, or by video inspection.
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Maintenance Objective Frequency and Maintenance Indications Typical Maintenance Activitie s Comments C a t c h B a s i n R e t r o f i t G S R D R e t r o f i t s H y d r o d y n a m i c S y s t e m s O i l W a t e r S e p a r a t o r s A b o v e g r o u n d D e t e n t i o n U n d e r g r o u n d D e t e n t i o n M e d i a F i l t r a t i o n V e g e t a t e d F i l t r a t i o n I n f i l t r a t i o n F a c i l i t i e s P o r o u s P a v e m e n t s Major clearing of sediment, trash, and debris • Prescribed clean-out schedule • Accumulated levels exceed threshold • Visual clogging • Accumulated levels affect BMP performance • Remove sediments for forebays, basins, and vaults of surface BMPs with backhoes or vactor equipment. • For underground BMPs, vactor sediments, debris, and water from sumps and chambers per DOT or manufacturer guidance.
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From page 101... ...
Maintenance Objective Frequency and Maintenance Indications Typical Maintenance Activitie s Comments C a t c h B a s i n R e t r o f i t G S R D R e t r o f i t s H y d r o d y n a m i c S y s t e m s O i l W a t e r S e p a r a t o r s A b o v e g r o u n d D e t e n t i o n U n d e r g r o u n d D e t e n t i o n M e d i a F i l t r a t i o n V e g e t a t e d F i l t r a t i o n I n f i l t r a t i o n F a c i l i t i e s P o r o u s P a v e m e n t s Remove oil • Per DOT schedule or manufacturer guidance • Oil-adsorbent pads are discolored or saturated • Oil accumulation in oil-water separators exceeds threshold (e.g.
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102 3. Identify information inputs: The purpose of this step is to identify the specific types of information and data needed to meet the study objectives.
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103 of monitoring objectives may require the use of decision rules, for example, maintenance triggers based on annual loadings or levels of accumulated sediments.
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