Restoration for Compliance: An Approach to Meeting Thermal Limits of a NPDES Permit

Why Leverage Water Quality Trading?

Water quality trading enables facilities to use the quantified benefits of restoration actions to meet NPDES permit requirements.

Restoration Actions for Water Quality & Quantity

ACTIONS RECOMMENDED AFTER ANALYSIS OF WATERSHED:

• Riparian re-vegetation

• Increase channel complexity

• Instream flow augmentation

Riparian Re-vegetation

ACTIONS:

• Replanting streamside vegetation

SUPPORTS:

• Reducing erosion and sedimentation instream

• Providing cooler shaded areas for aquatic organisms

• Increased complexity instream

Flow Augmentation

ACTIONS:

• Ensuring adequate water quantity throughout the year

SUPPORTS:

• Increasing instream flows can have a significant impact on instream temperatures by increasing instream velocities and hyporheic connectivity

Quantifying Ecological Uplift

• The benefits of a restoration action can be calculated in units for compliance (kilocalories per day), or in terms of ecological improvement (weighted linear feet of habitat)

• Models are constantly being improved and calibrated for this purpose

• Solar radiation is measured pre- and post- project implementation

• Reductions in solar radiation are the result of increased canopy cover for riparian re-vegetation or reduced channel surface area in channel modification projects

Models for Quantification: Shade-A-Lator

Models for Quantification: Water Temperature Transaction Tool

• Incoming solar radiation and atmospheric heat exchange are modeled pre- and post- project, taking into account landscape and meteorological parameters

• Increased flow buffers against heat exchange and lowers temperatures instream

• Just as models can be used to estimate thermal benefits, models can also estimate increases in habitat availability and improvement in ecological processes

• Investing in restoration for compliance is an investment in watershed health

• Important to monitor qualitative improvements to the local environment as well as quantitative water quality parameters

Models for Quantification: Ancillary Benefits

A Portfolio of Restoration Actions for Compliance

• Watershed assessment to evaluate number and location of potential restoration actions

• Thermal quantification of potential restoration actions at coarse scale: will require reference site evaluation to refine these estimates for credit development

• Ecological, social, economic feasibility assessment of thermal credits for compliance in the watershed

Next Steps