Forest Service Road Maintenance Series: Forest Roads and the Environment

Forest Service Road Maintenance Series: Forest Roads and the Environment


♪ Instrumental ♪ ♪ Instrumental ♪ ♪ Instrumental ♪ [cricket sounding] [birds chirping] [chicks squeeking] [eagle calling] (MALE NARRATOR)
EVERYWHERE YOU LOOK
IN THIS FOREST, YOU SEE THE SIGNS OF
AN ECOSYSTEM IN BALANCE– FROM THE HARDINESS OF THE
NATIVE PLANTS AND WILDLIFE, TO THE UNDISTURBED SOIL, AND CLEAR-RUNNING STREAMS. [truck engine revving] THERE ARE ROADS HERE, TOO. THEY’VE ALSO BECOME
AN INTEGRAL PART OF THE FOREST. THEIR CONDITION REFLECTS NOT
ONLY THE TECHNICAL KNOW-HOW OF THE PEOPLE WHO BUILD
AND MAINTAIN THEM, BUT ALSO A KEEN AWARENESS
OF THE SURROUNDING ENVIRONMENT, AND A CONCERN
FOR THE FOREST’S FUTURE, AND OUR OWN. WE’RE IN
THE CORONADO NATIONAL FOREST EAST OF TUCSON, ARIZONA, ON A ROAD THAT RUNS
FROM THE TURN-OFF BACK THERE, TO A LITTLE CAMPGROUND
ABOUT A MILE FURTHER DOWN. IN A WAY, THIS STRETCH OF ROAD
IS TYPICAL OF THE ROADS THROUGHOUT OUR
NATIONAL FOREST SYSTEM. NOT THAT THIS LOCATION
IS NECESSARILY TYPICAL. WE ALSO HAVE ROADS
IN NATIONAL FORESTS THAT ARE CLASSIFIED
AS RAINFOREST, OR EVEN HIGH DESERT. WHAT’S TYPICAL ABOUT THIS ROAD
IS THAT IT’S UNPAVED, IT SERVES MULTIPLE NEEDS, AND IT INTERACTS PROFOUNDLY
WITH ITS NATURAL SURROUNDINGS. WEAR AND TEAR
FROM TRAFFIC AND WEATHER MAKE IT NECESSARY
TO REPAIR THESE ROADS AND THEIR DRAINAGE SYSTEMS
PERIODICALLY. BUT, ADVANCES
IN SCIENCE AND TECHNOLOGY HAVE DRAMATICALLY IMPROVED
OUR UNDERSTANDING OF HOW TO GO ABOUT IT– IN WAYS THAT SUSTAIN
BOTH THE ROAD SYSTEM AND THE SURROUNDING
ENVIRONMENT. AFTER ALL, NATIONAL FORESTS ARE AMONG
OUR MOST VITAL ASSETS. AND WE NEED TO PRESERVE THEM
FOR GENERATIONS TO COME. ♪ Instrumental ♪ (NARRATOR)
FOREST SERVICE ROADS HOLD A UNIQUE PLACE,
BOTH IN OUR COUNTRY’S
TRANSPORTATION SYSTEM, AND IN THE
NATURAL ENVIRONMENT. THEY PROVIDE
READY ACCESS TO NATURE FOR THE TRAVELING PUBLIC, AND FACILITATE THE MANAGEMENT
OF NATURAL RESOURCES. WHEN ANY ROAD
FALLS INTO DISREPAIR AND REMAINS UNTENDED, IT CAN COMPROMISE
THE SAFETY OF DRIVERS AND THE HEALTH
OF NEIGHBORING ECOSYSTEMS. WHEN THAT ROAD RUNS THROUGH THE
COMPLEX ENVIRONMENT OF FORESTS, ENVIRONMENTAL CONSIDERATIONS
BECOME ESPECIALLY IMPORTANT. TO UNDERSTAND HOW A ROAD
INTERACTS WITH A FOREST, WE FIRST NEED TO LOOK AT
WHAT HAPPENS BETWEEN NATURAL ELEMENTS
WHEN THERE AREN’T ANY ROADS. IT’S AN EONS-OLD STORY
THAT BEGINS WITH WATER, AND SOIL. EACH FOREST
HAS A NUMBER OF WATERSHEDS THAT COLLECT WATER FROM RAIN,
AND MELTING ICE, AND SNOW, OR FROM RAINFALL ALONE. THE WATER FLOWS OVER AND
THROUGH THE FOREST FLOOR AS SURFACE FLOW
AND GROUNDWATER. AT FIRST,
IT MOVES SLOWLY DOWN SLOPE, DISPERSING OVER
A WIDE AREA. FORCEFUL BUILD-UP,
OR CONCENTRATION, WON’T NORMALLY OCCUR UNTIL THE WATER ENCOUNTERS
AND ENTERS SMALL STREAMS. FROM SMALLER STREAMS, IT TRAVELS
TO LARGER ONES, AND FINALLY,
INTO THE WATERSHED OUTLET– USUALLY A RIVER. A RIVER’S WATER REPRESENTS THE
ACCUMULATION OF GROUNDWATER, SURFACE FLOW,
AND STREAM FLOW. WHEN YOU ADD A ROAD
TO THIS PICTURE, YOU RISK INTERFERING
WITH THE NATURAL PROCESS. ROADS CAN INTERCEPT AND DIVERT
NATURAL DIFFUSED WATER FLOW, CONCENTRATING IT RANDOMLY
AND PREMATURELY. HERE, THE ROAD
HAS DIVERTED WATER FROM
ITS NATURAL DRAINAGE PATH. IT NO LONGER
DESCENDS DOWNSLOPE IN A NORMAL
DISPERSED PATTERN. INSTEAD,
IT’S BECOME CONCENTRATED, AND, IN EXTREME CONDITIONS,
MAY EVEN BECOME DISPLACED, OVERLOADING ONE WATERSHED,
OR SUB-WATERSHED, WHILE DEPLETING ANOTHER. ANOTHER POSSIBLE CONSEQUENCE
OF A CHANGE IN NORMAL
WATER FLOW PATTERNS IS FOR DITCHES AND CULVERTS
TO CONCENTRATE WATER RUNOFF SO THAT IT FLOWS DOWN TO SMALL
CHANNELS, STREAMS, AND RIVERS TOO QUICKLY, OVERBURDENING THEM
WITH A HIGHER THAN NORMAL
WATER ACCUMULATION, TAKING PLACE IN A SHORTER THAN
NORMAL TIME PERIOD– INCREASING THE EFFECTS
OF PEAK FLOW. LIKE WIND, RAIN, AND VEHICLE
OR EQUIPMENT TRAFFIC, WATER CONCENTRATION CAN BEGIN
THE PROCESS OF EROSION, SEPARATING SOIL PARTICLES
FROM THE GROUND, AND ALLOWING THEM
TO BE TRANSPORTED UNTIL THEY SETTLE OUT
IN OTHER PARTS OF THE FOREST, INCLUDING LAKES AND STREAMS. ONCE IN THE STREAM, THE SEDIMENT
CHANGES THE AQUATIC AND ADJACENT
RIPARIAN ECOSYSTEMS. IT COVERS UP AND FILLS IN
SPAWNING BEDS, SUFFOCATING FISH EGGS, INSECT LARVAE, AND OTHER ORGANISMS. THE SOIL
ALSO CLOUDS THE WATER, MAKING IT HARDER
FOR THE STREAM’S INHABITANTS TO LOCATE THEIR
DIMINISHING FOOD SUPPLY. THOSE THAT DO SURVIVE OFTEN SUFFER THE ABRASIVE
EFFECTS OF THE SOIL PARTICLES ON THEIR SENSITIVE
GILL TISSUES. SLOWLY BUT SURELY, AS THE SEDIMENT
SETTLES OUT, THE STREAM BECOMES
SHALLOWER AND WARMER — FURTHER LOWERING SURVIVAL RATES
OF EGGS AND FRY. THE RAISING
OF A STREAMBED ALSO CAUSES THE STREAM
TO BECOME WIDER TO ACCOMMODATE
THE NORMAL VOLUME OF WATER. THIS RESULTS
IN EROSION OF OVERHANGS– THE SHADY INTERLOCKING
MASSES OF VEGETATION THAT NORMALLY PROVIDE
A SANCTUARY FOR AQUATIC LIFE TO HIDE, REST, AND FEED. AS USUAL IN AN ECOSYSTEM, LOCAL IMPACTS
DON’T REMAIN LOCAL. AS SMALL CREEKS BECOME
SEDIMENT-LADEN AND WARM UP, THEY, IN TURN, WARM,
AND OTHERWISE ALTER, LARGER ONES DOWNSTREAM. NEIGHBORING HUMAN COMMUNITIES
AREN’T EXEMPT EITHER. SEDIMENT INCREASES THE COST
OF PURIFYING DRINKING WATER, AND FILLS IN
RESERVOIRS AND CANALS. IT CAN EVEN DAMAGE
TURBINE GENERATORS
IN HYDROELECTRIC FACILITIES. SOME EFFECTS ARE HARDER
TO MEASURE THAN OTHERS. HOW CAN YOU CALCULATE THE COST
OF LOSING A CHOICE FISHING HOLE, OR A FAVORITE HIKING TRAIL,
OR CAMPSITE? (HOST)
OF COURSE, QUESTIONS LIKE THAT
ARE IMPOSSIBLE TO ANSWER. BUT THERE’S
A RELATED QUESTION THOSE OF US
WHO MAINTAIN FOREST ROADS ASK EVERYDAY– HOW CAN WE HAVE THE ROADS
WE NEED AND SAFEGUARD
THE ENVIRONMENT? THE ANSWER CAN BE FOUND
IN THE EARLIER QUESTION OF WHERE THE WATER WOULD GO IF
THE ROAD DIDN’T EXIST. DO EVERYTHING YOU CAN TO EMULATE
THE WAY NATURE MOVES WATER AND YOU MINIMIZE DISTURBANCE
TO BOTH THE ROAD AND ITS
NATURAL SURROUNDINGS. (NARRATOR)
THE KEY TO PUTTING THAT
PRINCIPLE INTO PRACTICE IS DISPERSING,
RATHER THAN CONCENTRATING, ROAD-DIVERTED WATER FLOW. THAT MEANS USING THE MOST
EFFECTIVE MEASURES AVAILABLE FOR CONTROLLING THE VOLUME
AND VELOCITY OF WATER. THE FIRST STEP IS TO MAKE SURE
THE TRAFFIC-BEARING PORTION
OF THE ROAD– ALSO KNOWN AS
THE TRAVELED WAY– HAS AND MAINTAINS
A PROPERLY DEFINED SHAPE. WATER SHOULD MOVE OFF
THAT SURFACE EFFICIENTLY SO THAT IT DOESN’T
DEGRADE THE ROAD. WHENEVER POSSIBLE, THE WATER SHOULD BE RELEASED
INTO THE FOREST IN A WELL DISPERSED PATTERN THAT DOESN’T DISTURB
SURROUNDING SOIL. IN MAINTAINING
DRAINAGE STRUCTURES LIKE THIS LEAD OUT DITCH, IT’S IMPORTANT TO IMITATE
NATURE’S WAY OF PROTECTING
EXPOSED AREAS. VEGETATIVE MATERIALS
LIKE THESE REDUCE THE SPEED, AND,
TO A LESSER DEGREE, THE CONCENTRATION
OF THE WATER. SO DO DITCH DAMS
AND OTHER BARRIERS. THE FLOW CAN ALSO BE CHANNELED INTO FLAT, VEGETATED AREAS
OF FOREST FLOOR, ALLOWING THE WATER
TO SOAK INTO THE GROUND, LEAVING THE SEDIMENT BEHIND. ONE OF OUR
PRIMARY OBJECTIVES WHEN DEALING
WITH ROAD DRAINAGE IS TO REDUCE OR
ELIMINATE FINE SEDIMENT FROM ENTERING
THE STREAM CHANNEL. AND A PARTICULARLY
EFFECTIVE WAY TO DO THAT IS TO PROVIDE
A BUFFER STRIP BETWEEN THE ROAD
AND THE STREAM, AND THAT BUFFER STRIP
CAN CONSIST OF GRASS, OR SOMETHING CONSIDERABLY
MORE DENSE LIKE BRUSH. WHAT THAT DOES IS IT ALLOWS THE VELOCITY
TO DROP ENOUGH THAT THE FINE SEDIMENT
SETTLES OUT BEFORE ENTERING
THE STREAM CHANNEL. (NARRATOR)
SETTLING PONDS ARE ANOTHER
EFFECTIVE WATER CONTROL MEASURE. THEY DO JUST WHAT
THEIR NAME IMPLIES– INTERRUPTING AND SLOWING DOWN
THE WATER FLOW SO THAT SEDIMENT
CAN SETTLE OUT, RATHER THAN CONTINUE ITS JOURNEY
TO OTHER PARTS OF THE FOREST. OF COURSE, THESE MANMADE SYSTEMS ARE
ONLY AS GOOD AS THEIR UPKEEP. BUT, WITH REGULAR CARE, THEY FUNCTION EFFECTIVELY AS PART OF
THE FOREST’S DEFENSE AGAINST
EROSION AND SEDIMENTATION CAUSED BY
CONCENTRATED WATER FLOW. OF COURSE,
AS WE’VE SEEN, TOO LITTLE WATER IS THE
OTHER SIDE OF THE PROBLEM. WHEN A ROAD DIVERTS WATER
FROM ITS NORMAL FLOW PATH, AND UNNATURALLY
CONCENTRATES IT, THE FLOW MAY ERODE
THE GROUND SO DEEP THAT IT’S BELOW
THE NATURAL WATER TABLE. THIS CAUSES THE WATER LEVEL
TO DROP, KILLING SHALLOW ROOTED GRASSES
AND OTHER VEGETATION. THAT CAN UPSET
THE NATURAL BALANCE BETWEEN AND WITHIN THE FOREST’S
PLANT AND ANIMAL SPECIES– ULTIMATELY LEADING TO
EVEN MORE EROSION AND RELATED CHANGES
TO THE FOREST. FOR EXAMPLE, IF SHALLOW-ROOTED GRASSES
AND OTHER GROUNDCOVER PLANTS
DIE OFF, THEY’RE NO LONGER ABLE TO HELP
HOLD THE SOIL TOGETHER, AND TO SLOW AND DISPERSE
CONCENTRATED WATER. WHEN RAIN DOES COME, IT FALLS ON SOIL THAT’S MUCH
MORE SUSCEPTIBLE TO EROSION. OF COURSE,
NO MATTER HOW SKILLFULLY
YOU MAINTAIN THE ROADS, IT JUST ISN’T POSSIBLE
TO STOP ALL EROSION, BUT IT IS POSSIBLE
TO MINIMIZE OR MODIFY IT– EVEN IN
EXTREME CONDITIONS. HERE IN THE SONORAN DESERT
OF THE CORONADO NATIONAL FOREST
IN SOUTHERN ARIZONA, THERE’S LESS THAN 12 INCHES
OF RAINFALL A YEAR. CONDUCTING NECESSARY REPAIRS
ON THESE ROADWAYS CAN SERIOUSLY REDUCE
THEIR SURFACE COHESIVENESS IF DONE WITHOUT
PROPER MOISTURE CONTENT. LEFT UNTREATED, THE SOIL COULD SOON BE
CARRIED AWAY BY THE WIND, AND BY WHATEVER PRECIPITATION
DOES OCCUR. SO, IN A PLACE LIKE THIS, DURING OPERATIONS
LIKE BLADING, IT’S ESPECIALLY IMPORTANT TO KEEP THE PROPER MOISTURE
CONTENT IN THE ROAD SURFACE TO ALLOW PROPER SHAPING. THIS MAY MEAN
MECHANICALLY SPRAYING
THE ROAD SURFACE WITH WATER, OR SCHEDULING ROADWORK
SOON AFTER A RAINFALL. IN ANY LOCATION, BUT ESPECIALLY A DRY ONE
LIKE THIS, COMPACTING THE ROAD IMMEDIATELY
FOLLOWING BLADING OPERATIONS IS ESSENTIAL TO IMPROVING
THE SOIL’S COHESIVENESS. IN SOME SITUATIONS, SOIL-STABILIZING ADDITIVES
MAY ALSO BE NEEDED. HERE, AS IN ALL FOREST SERVICE
ROAD MAINTENANCE, THE NEW AND IMPROVED
RULE OF THUMB IS “DISTURB THE SOIL ONLY WHEN
ABSOLUTELY NECESSARY. AND, WHEN IT IS NECESSARY,
USE A LIGHT TOUCH.” DOES THIS ROADSIDE DITCH
NEED CLEARING AND RESHAPING? ONLY IF IT’S SENDING WATER
BACK ONTO THE ROAD, OR OTHERWISE
FUNCTIONING IMPROPERLY. EXPERIENCE AND RESEARCH
HAVE TAUGHT US THAT “CLEANER AND CLEARER”
ISN’T ALWAYS “BETTER” WHEN IT COMES TO
PROTECTING FOREST SOIL. (NARRATOR)
IN FACT, THESE ROCKS AND PLANTS
ARE HELPING TO SLOW THE FLOW OF WATER
THROUGH THE DITCH AND HOLD THE SOIL TOGETHER. IN LIGHT OF MODERN MAINTENANCE
POLICIES AND PRACTICES, THE PRESENCE OF A ROAD
IN A FOREST DOESN’T HAVE TO SIGNAL THE
PRESENCE OF EXCESSIVE EROSION AND ITS CONSEQUENCES– FROM STREAM SEDIMENTATION
TO POSSIBLE SLOPE FAILURE. PEACEFUL CO-EXISTENCE BETWEEN A
ROAD SYSTEM AND AN ECOSYSTEM IS NOTHING
TO TAKE FOR GRANTED. IT DEMANDS A GREAT DEAL OF
PLANNING, CARE, AND SKILL, BUT IT CAN BE ACHIEVED, AND THE STAKES
COULDN’T BE MUCH HIGHER. AND, SURELY,
THE EFFORT IS WORTHWHILE. NATIONAL FOREST ROADS AREN’T JUST A MEANS OF ACCESSING
AND MANAGING RESOURCES, OR GETTING FROM
ONE PLACE TO ANOTHER BY WAY OF
“THE SCENIC ROUTE.” THEIR CONDITION DIRECTLY IMPACTS
THE HEALTH AND LONGEVITY OF A LIVING TREASURE WHOSE IMPORTANCE WE’RE JUST
BEGINNING TO FULLY UNDERSTAND. WHETHER OR NOT FORESTS
LIKE THIS ONE CONTINUE TO
THRIVE AND PROSPER DEPENDS LARGELY ON HOW
WE DO OUR JOBS. FOR THE MEN AND WOMEN
WHO WORK HANDS-ON TO MAINTAIN
UNPAVED SECONDARY ROADS, THE TASK COULDN’T BE
MORE IMPORTANT OR REWARDING– TO TRULY MAKE A DIFFERENCE
IN THE NATURAL WORLD BY HELPING TO PRESERVE AND
SUSTAIN OUR NATIONAL HERITAGE FOR GENERATIONS TO COME. ♪ Instrumental ♪

One thought on “Forest Service Road Maintenance Series: Forest Roads and the Environment”

  • The US Forest Service needs to stop spending money on videos and keep the roads open that they are closing at a alarming rate. They are doing everything they can to keep the public out of public lands.

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