Site Characterization and Adapted Monitoring of a Flood-Disturbed Reclamation Area

Transcription

1 Durango, CO Cortez, CO Pagosa Springs, CO Santa Fe, NM Farmington, NM Site Characterization and Adapted Monitoring of a Flood-Disturbed Reclamation Area Swastika/Dillon Canyon Reclamation Project Raton, NM

2 Location Located on Vermejo Park Ranch west of Raton, NM Coal mining early 1900s into the 1950s

3 History Gob piles from Swastika Mine Blocked Dillon Canyon drainage Eroded coal waste into stream Leached chemicals into drainage Source; EMNRD AMLP

4 History Stream artificially straightened for railroad and coal loadout access Caused severe incising of channel Created channel instability, including down-cutting and bank erosion

5 History NM EMNRD AMLP completed reclamation work Relocated straightened stream channel away from gob Re-incorporated sinuosity Capped gob piles Installed erosion control and mitigation plantings

6 History Completed under USACE NWP 27 Ecosphere hired to start monitoring in 2014

7 History Flash floods in Fall 2013 USACE needs: Re-characterization of existing conditions Re-evaluation of mitigation and monitoring activities Revised reporting in 2014 instead of monitoring Full monitoring and reporting to begin in 2015 Additional discussions on future monitoring and reclamation/remediation requirements

8 Goals and Objectives Collect post-flood baseline data Determine recovery status of affected reaches Identify the need for channel stabilization and grade control Identify if supplemental plantings needed Determine if reclamation performance standards are being met, could be met, or need to be modified Determine if monitoring protocols need to be modified

9 Challenges Cultural sites Recurring large run-off events Meeting USACE permit performance standards requirements

10 Methods Rapid Response Evaluation Reach Characterization Data Form 14 reaches and 2 wetland areas identified and evaluated Compared existing conditions in reclaimed area with undisturbed areas Generated ratings for vegetation, hydrology, and soil conditions for each reach

11 Methods Vegetation Ratings: 1 = Ideal existing vegetation is adequate, no modifications required 2 = Minor Planting limited planting recommended, but optional 3 = Major Planting no wetland species currently identified in reach, major supplemental planting recommended 4 = Major Planting with channel modification major supplemental planting and channel stabilization or control structures are recommended

12 Methods Soil Ratings: Soil saturation, soil texture and depth, chroma, and hydric soil indicators recorded No ranking since soils heavily impacted by reclamation and flooding

13 Methods Hydrology Ratings: 1 = Good channel form and hydrology stable banks and no evidence of headcutting, no channel stabilization and grade control measures recommended 2 = Good hydrology, but channel form is not optimal stabilization or grade control measures optional 3 = Minor mechanical modifications required 4 = Bank stabilization or grade control structures required

14 Methods Cost/Benefit Determinations Rating of 3-4 = little work required Rating of 5-6 = moderate work required Rating of 7-8 = significant work required to bring the reach into compliance Rating of A = good wetland enhancement potential with structural modifications and additional plantings Rating of B = little improvement anticipated even with additional plantings and structural modifications

15 Results All but one reach exceeded 15% total vegetative cover by 2nd growing season (by ocular estimate) (reclamation performance standard) 3 reaches No supplemental planting needed 3 reaches Benefit from plantings, but not mandatory 10 remaining reaches Supplemental plantings needed 8 reaches Need channel stability or grade control remediation measures 7 reaches Good cost/benefit ratio for remediation work

16 Conclusions Vegetation and channel stability goals needed assistance at some sites/reaches Vegetation in the project area within parameters of performance standards No changes to the reclamation performance standards recommended Monitoring methodology needed to be modified to better capture vegetation density and diversity

17 Goals and Objectives Met? Collect post-flood baseline data Determine recovery status of affected reaches Identify if supplemental plantings needed Identify in-channel stabilization or grade control areas Determine if reclamation performance standards are being met, could be met, or need to be modified Determine if monitoring protocols need to be modified

18 2015 Project Updates Used Rapid Characterization data form to compare reaches from 2014 to 2015 First monitoring year using modified approach 2015 storm events continued to impact reclamation area High bedload volumes, channel incision, and channel instability continue to prevent vegetation establishment In-channel stabilization design and planning is underway and expected to be implemented in

19 Acknowledgements Special thanks to: Mark Oliver from Basin Hydrology, Inc. (Durango, CO), who was instrumental in the development and implementation of the geomorphic reach analysis on this project Ken Carlson and Robin Bay of Habitat Management, Inc. (Englewood, CO) Richard Spotts, P.E. and Kate Malers, P.E. of Water and Earth Technologies, Inc. (Fort Collins, CO)

20 Questions? Lower Reach 10 looking upstream 07/24/2013 after high-flow event 08/19/2014 two years post-construction 08/19/2015 three years post-construction