2011 DOE Biomass Program Review Effectiveness of low impact development practices in two urbanized watersheds: Retrofitting with rain barrels/cisterns and porous pavements Laurent Ahiablame Prof. Bernard Engel, Prof. Indrajeet Chaubey Date, 2012 RD&D Project Presentation Template

The Problem How effective are LID practices at the watershed scale? LID practices - lot level control measures Current focus of research – runoff management with LID practices. Impacts of LID practices on baseflow need to be investigated at the lot scale at the watershed scale

How to Proceed? Monitoring – most appropriate (perhaps), expensive, time consuming, sometimes impossible. Modeling – convenient, less expensive, time efficient, sometimes may be complex. Modeling – L-THIA-LID

L-THIA Modeling of LID Practices Standard procedure for LID modeling Representation of LID practices CN values Consideration of design guidelines Sizing factors Computation of runoff, baseflow, total flow Threshold area: IF watershed area ≥ 120 ha => baseflow Computation of LID effectiveness index Baseflow core equation Regression model for Indiana conditions Relationship between baseflow and LID practice BFI versus CN Baseflow pollutant coefficients Three methods for calculating BFI values

Improving L-THIA-LID LID practices currently represented in L-THIA-LID Bioretention/rain garden Open wooded space Porous pavement Swale Porous pavement + swale Permeable patio Green roof Disconnected impervious surfaces

LID Effectiveness Index Improving L-THIA-LID Runoff (distributed approach) Baseflow LID Effectiveness Index L-THIA-LID Interface (VBA)

Little Eagle creek Little Buck creek Little Eagle Creek   Little Eagle Creek Little Buck Creek Land use Area (ha) Percent Low Density Residential 3872.8 54.8 3273.0 74.1 Commercial/Industrial 2260.2 32.0 538.9 12.2 High Density Residential 271.0 3.8 1.4 0.0 Road/Street 573.6 8.1 366.3 8.3 Bare soil 16.0 0.2 - Grass/Pasture 77.4 1.1 238.2 5.4 Total 7070.9 4417.7 Calibration period 1991-200; validation period 2001-2010; application period 1991-2010 Scenario Description S1 existing condition S2 25% rain barrel/cistern S3 50% rain barrel/cistern S4 25% porous pavement S5 50% porous pavement S6 S2 + S4

Little Eagle Creek LID Scenario Runs: 1991-2010   Flow (%) TP (%) TN (%) Runoff Scenario 2 6 5 Scenario 3 11 12 Scenario 4 3 Scenario 5 Scenario 6 8 9 Baseflow -1 -2 Total flow 2 1 4 7 LID Scenario Runs: 1991-2010 Effectiveness of LID practices

Little Buck Creek LID Scenario Runs: 1991-2010   Flow (%) TP (%) TN (%) Runoff Scenario 2 3 2 Scenario 3 5 6 Scenario 4 4 Scenario 5 8 7 Scenario 6 Baseflow -1 Total flow 1 LID Scenario Runs: 1991-2010 Effectiveness of LID practices

Summary Simulated runoff, baseflow, and total flow for the baseline compared well with observed values during calibration and validation periods. Calibration: R2 and NSE > 0.5 Validation: R2 > 0.4; NSE > 0.3 Effectiveness of LID practices at the watershed scale Runoff + pollutants: 2 to 12% Baseflow + pollutants: -1 to -2% Total flow + pollutants: 1 to 9% Good LID options for retrofitting in urbanized watershed 25% rain barrel/cistern adoption 25% porous pavement adoption 25% rain barrel/cistern + 25% of porous pavement adoption Baseflow was not calibrated as baseflow was previous developed and validated for Indiana conditions. These LID options can be used to retrofit urbanized watershed without any taking down any buildings, without further disturbing watershed existing condition.