FLOOD05850

• County: Montezuma
• Stream Name: Dolores River
• Basin: San Juan/Dolores
• Title: Field Report - The Dolores River
• Date: 11/1/2001
• Prepared By: CWCB, DNR
• Floodplain - Doc Type: Floodplain Report/Masterplan

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DOLORES RIVER GRAVEL PIT IMP ACT

July 18, 2001

To CFAR Committee

INTRODUCTION

I was asked by Pat Kantor to provide a summary of the hydrologic impacts that might
occur from the impact of gravel pit mining in the Dolores River valley above the town of
Dolores. I have not limited myself to the hydrology because this is a systems problem not
just a simple cause and effect.

I am interested in the Dolores River System including its geologic history and current
state. Presently my concern is with the human impact upon the river that could lead to the
general degradation and value of the river and to the increased potential of flood hazard
to downstream residents.

The floodplain areas of the Dolores River are subject to periodic inlUldation that may
result in loss of life and property, health and safety hazards, disruption of commerce and
governmental services, extraordinary public expenditures for flood protection and relief,
and impairment of the tax base, all of which adversely affects the public health, safety,
and general welfare. There have been eight flood events greater than 6,000 cfs and three
greater than 8,000 cfs in the past 90 years.

QUESTIONS NOT ADEQUATELY ANSWERED
. '.' .
',':,-
l,;Wkt ;:e1he accuroulati;e hnpacts of multiple gravel pit mining activities and
pits on the floodplain of the Dolores River?
2, Do these activities and their modifications to the landscape increase the damage
, iriburred by natural flooding?
3. What other negative impacts do these activities have upon the general welfare of
the community and users?
4. What are the limits of modification of the channel that can be tolerated by the '
river system without severely increasing flood hazard?

These and other questions can only be tackled from a systematic study of the Dolores
River Drainage watershed. I believe that a systems approach to the watershed is the best
strategy because it does not just limit itself to the impact of gravel mining but to the
impact ,of all human and natural processes.

GRAVEL MINING

Gravel is an important resource for our industrialized culture. In the U.S. 11 tons per
person of stone and aggregate are consumed each year for roads, buildings and other
construction projects. Thus, good gravel sources are modern day "gold mines." Gravel