Overcoming Obstacles: Real LID Projects with Real Solutions Jerry P. Preston, P.E., CFM Department Manager – Hydrology & Hydraulics EHRA jpreston@ehrainc.com 2014 LID in Houston Workshop, April 3, 2014

Objectives Moving from LID Concepts to “real-world” applications Share ideas and information Learn from experience and continually improve LID design and implementation Objectives 2014 LID in Houston Workshop, April 3, 2014

CHALLENGES Sjolander Road Harris Co. Pct 2 Baytown, Texas Flat terrain (natural ground slope +/- 0.03%) Shallow Outfall Depth Pipeline Crossings (+/-40 pipelines in three separate corridors in one-mile project) Raw Water Canal Crossing Contributing Offsite Drainage Area ~250 ac Sjolander Road Harris Co. Pct 2 Baytown, Texas 2014 LID in Houston Workshop, April 3, 2014

Linear Bioswales along roadway for detention storage, conveyance, SWQ SOLUTIONS Linear Bioswales along roadway for detention storage, conveyance, SWQ “False-back” Inlets Bioswales shallower than Storm Sewer Strategic placement of Drainage Divides to avoid pipeline and raw water canal conflicts Sjolander Road Harris Co. Pct 2 Baytown, Texas 2014 LID in Houston Workshop, April 3, 2014

Sjolander Road Harris Co. Pct 2 Baytown, Texas POST-CONSTRUCTION LESSONS LEARNED Long, flat grades - consider extended underdrain and use multiple engineered soil filter “inlets” Construction tolerances – standing water critical for proposed landscape areas Siltation at Engineered Soil Filter – use temporary “bypass” drain during construction Sjolander Road Harris Co. Pct 2 Baytown, Texas 2014 LID in Houston Workshop, April 3, 2014

CHALLENGES/SOLUTIONS Topography! - approx. 30’-40’ elevation change along proposed roadway required multiple “drops” to obtain effective storage along road Mossy Oaks Boulevard Northern Harris Co, Texas 2014 LID in Houston Workshop, April 3, 2014

CHALLENGES/SOLUTIONS Restricted ROW width (100’) – needed additional ROW width in select locations due to topography Mossy Oaks Boulevard Northern Harris Co, Texas 2014 LID in Houston Workshop, April 3, 2014

POST-CONSTRUCTION LESSONS LEARNED Erosion/rilling at slotted curb openings – provide sod strip or erosion control mat Siltation at Engineered Soil Filter – use temporary “bypass” drain during construction Mossy Oaks Boulevard Northern Harris Co, Texas 2014 LID in Houston Workshop, April 3, 2014

Convert temporary drain to permanent observation port/cleanout Siltation at Engineered Soil Filter – use temporary “bypass” or overflow drain during construction Convert temporary drain to permanent observation port/cleanout Other Lessons Learned and Remaining Challenges 2014 LID in Houston Workshop, April 3, 2014

Other Lessons Learned and Remaining Challenges Perforated Underdrains/Rain Tanks – strategic use of impermeable liners to prevent erosion or washouts in unwanted locations Other Lessons Learned and Remaining Challenges 2014 LID in Houston Workshop, April 3, 2014

Other Lessons Learned and Remaining Challenges Construction Staging – temporary drainage always requires coordination and planning Construction Sequencing considerations for permeable pavers and engineered soils Other Lessons Learned and Remaining Challenges 2014 LID in Houston Workshop, April 3, 2014

New design and construction techniques mean we’re learning on the fly LID drainage can provide drainage and detention benefits, improved storm water quality, land use efficiency, improved aesthetics New design and construction techniques mean we’re learning on the fly Continuing Education process Conclusion 2014 LID in Houston Workshop, April 3, 2014

Thank You – Questions? Jerry P. Preston, P.E., CFM Department Manager – Hydrology & Hydraulics EHRA jpreston@ehrainc.com 2014 LID in Houston Workshop, April 3, 2014