Float 'N Fish San Juan General Information
San Juan River water Sources and related river systems

The San Juan River flowing below Navajo Dam originates high in the San Juan Mountains of southwest Colorado.  These high mountains contain several peaks over 14,000 ft which draw significant snowpacks as moisture moves inland.  The San Juan Mountains are an important water source for the state of New Mexico as the San Juan and Rio Grande river systems formed in southwest Colorado provide the an important contrubution to surface water of all river systems flowing through New Mexico, although the two river systems are located on opposite sides of the continental divide.  The San Juan Mountains are located in southwest Colorado on the continental divide with eastern slopes sending water to the Atlantic Ocean and western slopes flowing to the Pacific Ocean.  The eastern slopes of the San Juans form the upper ranges of the Rio Grande River which flows through south central Colorado, through central New Mexico and forms the western border for Texas as it flows all the way to the Gulf of Mexico.  Northern slopes of the San Juans contribute to the Gunnison River, among others, in western Colorado which join the Colorado River on its way to Lake Powell, the Grand Canyon and eventually the Pacific Ocean.  The San Juan River is increased in volume by contributions from the Animas and La Plata rivers near Farmington and joins the Colorado River after turning northwest past Farmington,  passing briefly through Colorado near the Four Corners Monument and continuing to the eastern San Juan branch of Lake Powell in southeast Utah. 

The San Juan River forms on the south facing slopes of the San Juan mountains flowing to the southwest through Pagosa Springs, CO and then joins the Navajo River before it runs into Navajo Resiorvoir (Navajo Lake) near the Colorado / New Mexico border east of Arboles, CO.  Also contributing to Navajo Lake are the Piedra River and the Los Pinos.  The Piedra River is formed from smaller streams high in the San Juan Mountains on southern slopes east of the San Juan headwaters and northwest of Pagosa Springs, CO.    The Piedra flows in a general southerly direction until it empties into the largest branch of Navajo Lake near Arboles in southern Colorado.  The third major contributor to Navajo Lake is the Los Pinos River.  The Los Pinos forms in the slopes north of Vallecito, CO where it is dammed forming Vallecito Reservoir.  From the reservoir the Los Pinos flows south past Bayfield, CO and then Ignacio, CO  to enter Navajo Reservoir a little south of the Colorado border.  As you drive from Navajo Dam, NM north to Ignacio, CO  on NM 511 you parallel the branch of Navajo Lake formed from the Los Pinos river.  The Bureau of Reclamation has diverted about 110,000 acre feet of water annually across the continental divide from Navajo Dam tributaries to tributaries of Lake Heron in NM and thus to the Rio Grand System.  Most of this diverted water is for municipal use by several municipalities on the middle Rio Grande valley, although some is used for irrigation.  Downstream from the town of Navajo dam another major water source from the San Juan Mountains joins the San Juan river near Farmington.  The Animas river is formed high in the San Juans near Silverton, CO, flows through Durango, CO eventually joining the San Juan river with its confluence near Farmington, NM.  The Animas river system is a significant river system although smaller than the San Juan with an annual yield a little more than 2/3 that of the San Juan below Navajo Dam. 

This area was first thought to have been explored by Europreans in the late 1700's.  During this time Capt. Juan Marie de Rivera (1765) and Padre Francisco Escalante explored parts of San Juan county from Santa Fe.  During the Escalante Expedition in 1776, many of the areas rivers were named including the San Juan (Rio San Juan - St. John River), Piedra (Rio de las Piedras - Stony River), Animas (Rio de las Animas Perdidas - River of Lost Souls), Los Pinos (Rio de los Pinos - Pine River) and Florida (Rio Florida - River of Flowers). 

Sage Logo           Sage Rods                              Sage Reels

Simms Logo           Simms Waders             Simms Wading Boots          Simms Layering             Simms Vests          Simms Wading Jackets

Navajo Dam History

The San Juan river was a free flowing river prior to July 1958 when the Bureau of Reclamation started bulding Navajo Dam, the dam being dedicated in September 1962.  The dam is an earth filled dam over 2/3 mile in length with a height slightly over 400 ft.  Prior to the dam being completed the San Juan river was a fishery with Rainbows, Browns and Cutthroats as well as some warm water species, although the water was warmer and often carried more silt than today.  The top of the dam is located at an eleveation of 6,108 ft (Bureau of Reclamation) with the riverbed below the dam at about 5,720 ft.  Navajo Lake provides storage for a drainage area of 3,190 square miles in southwest Colorado and northwest New Mexico.  From the dam at Navajo Reservoir, the lake forms 2 major branches extending north and northeast.  The Pine River branch (Los Pinos), extends approximately 13 miles north through high desert canyons to near the Colorado Border.  The midde branch, formed from the Piedra and San Juan Rivers, extends 35 miles in a northeasterly direction all the way past the state line to near Arboles, CO.  As you near the Colorado border, the terrarin looses some of it's high desert canyon character as the elevation increases and more moisture is available.

Serious consideration for building a dam at the present site began in about 1930 based on investigations of the area dating back to about 1904.  Funding for the dam project was not available until the 1950's when Congress funded the project by making the dam part of the Colorado River Storage Project (Bureau of Reclamation).  The dam was built to provide the benefits of a siltation basin, flood control, recreation and water for irrigation and industry.  As part of the funding agreement, the dam was to provide water for the Navajo indian tribe to irrigate approximately 110,000 acres of the NIIP (Navajo Indian Irrigation Project) southeast of Farmington.  In addition to the NIIP Project, the enabling legislation to build the dam provided for a diversion of some SJ basin waters through the Continental Divide to the Rio Grande as the San Juan Chama Project.  In the 1980's, a 30 Megawatt capacity hydroelectric plant was completed at the base of the dam by the city of Farmington adding benefits to the existing structure. 

Indigenous Peoples of northwest New Mexico, northeast Arizona, southwest Colorado, and southeast Utah

Archaeologists believe that some of the earliest known humans in North America inhabited parts of New Mexico, these are referred to as the Clovis People.  The Clovis People were big game hunters as demonstrated by their distinct arrowheads and spear points, these points being named Clovis Points after the people.  The Clovis people got their name from the NM town in southeast NM where they were first discovered.  The Clovis people are estimated to have lived in this area 11,000 - 13,500 years ago following the last ice age, depending on what type of dating is used.  Evidence indicates that the Clovis People hunted mammoth, horse and camels prior to these animals extinction in NM.  Although the evidence is less clear, there is some evidence that indicates that humans may have been living in NM as early as 20,000 years ago.  The Clovis culture was followed by the Folsom people.  As Clovis and Folsom people hunted primarily in small bands following game animals.  These cultures did not leave behind structures and are primarily identifiable by remains of small hunting camps where various artifacts have been left behind. 

The area around the San Juan river has an extensive history with indigenous peoples.  Ancient ruins near Bloomfield, Aztec, Chaco Canyon and Mesa Verde provide an insight into the lives and culture of native peoples from about 750BC through 1300BC.  The fate of these early inhabitants, the Anasazi, is not certain as the culture has disappeared without records.  The Anasazi are believed to be the ancestors of the modern day pueblo peoples, may have merged with other tribes, died out, or were displaced by incoming more powerful peoples.  In more modern times, three indian tribes are known to have lived in the San Juan area.  These tribes are believed to have migrated to the four corners from the north, some as far as northern Canada.  These three tribes are present in the area today and a fourth, the Southern Ute's has relocated to the area.  The largest of these tribes, the Navajo, inhabit parts of northwest New Mexico, northeast Arizona and southeast Utah.   The Navajo indian reservation is the largest in the US and is home to the largest native american indian tribe in the country.  The Navajo in NM today are located primarily south of the San Juan River from near Farmington south to Gallup, and north to the Colorado border from the Farmington area.  North of the Navajo in in southwest Colorado are found two branches of the Ute tribe.  The Southern Utes occupy parts of southwest Colorado north and west of Navajo Lake east to north of Dulce, NM, their reservation residing entirely along the southern Colorado border below Highway 160.  The main tributaries to Navajo Lake pass through Southern Ute territory as well as the Animas further west.  The tribal headquarters of the Southern Utes is in Ignacio, CO.  The original range of the Southern Utes included the eastern slopes of the front range near Denver, CO down to near Las Vegas, NM, and the San Luis valley in south central Colorado.  The Southern Utes relocated to their present location following a treaty in 1880.  The Ute Mountain Ute tribe is located in southwest Colorado bordered on the east with the Southern Ute reservation and on the west at the Colorado / Utah border,  with tribal headquarters at Towac, CO, south of Cortez, CO.  This band of the Ute tribe was found north of the Navajo around the San Juan river in southwest Colorado, northwest New Mexico and southeast Utah.  The third tribe in the area today is the Jicarilla Apache found in the Dulce, NM area directly east of present day Navajo Lake.  From Dulce, the Jicarilla Apache reservation extends southward and then southwest to an area northwest of Cuba, NM.  The original range of the Jicarilla Apache included much of northeastern NM and southeastern Colorado.   Navajo Reservoir and the San Juan River below the dam are bordered on three sides by present day indian reservations including Southern Utes to the north, the Jicarilla Apache to the east and the Navajo to the west. 

1.  Paleoindian and Arahaic Peoples 5.  Chaco Canyon - National Historic Park
2The Salmon Ruins 6.  Aztec Ruins National Monument
3Chaco Culture National Historical Park  
4.  Mesa Verde - National Park Service  

San Juan Rivers and Indian Reservations


Geologists have divided geologic time into several periods going back over 600 million years ago.  The granite in some of New Mexico's high mountains is thought to come from the earliest period called the Precambrian, more than 540 million years ago.  This granite is found mostly in the high mountains of north central NM.  During the next period of time in NM, the Paleozoic, from approximately 250 - 540 million years ago, shallow seas left a history in fossils and sedimentary rock.  Following the Paleozoic is the Mesozoic, from about 65 - 250 million years ago.  This is the period of the dinosaurs and many species have been demonstrated to have lived in NM including San Juan county, although seas remained in some parts of the state.  The latest period, the Cenozoic, from 65 million years ago to the present led to the current NM desert environment.  It is during this period that NM's mountain ranges developed and the seas present in earlier times disappeared.  Volcanic activity reshaped the terrain in many places and large mammals replaced the reptiles of earlier ages.  Mammoths and camels among other mammals roamed the landscape in a cooler climate. 

Navajo Reservoir and the San Juan River lie on the eastern side of a large geological formation called the Colorado Plateau.  The Colorado Plateau extends from the four corners area east to about the Rio Grand River, west deep into Arizona and near Salt Lake City in Utah, north well past Grand Junction in Colorado and south in NM below Interstate 40.  Rocks from the Cambrian period to the Cenozoic period are present in the San Juan Basin portion of the Colorado Plateau, but not always on the surface.   The area of the San Juan River immediately below the dam and Navajo Lake is comprised primarily of sedimentary rock from the Tertiary and Quaternary time frames of the Cenozoic period.  Sediment carried downstream from the San Juan Mountains and the lower portion of the Rocky Mountains formed 40 - 80 million years ago filled the San Juan Basin forming the sedimentary rock you see today on the canyon walls of the San Juan river and along the shores of Navajo Lake.  These sedimentary rocks are primarily various sandstones and some shales. 

1NMBGMR Geologic Tour:  Navajo Lake State Park 5.  NM Fossils
2The San Juan Mountains  
3USGS  A Tapestry of Time and Terrain  
4.  The Paleontology Portal  

Stream Improvements

Several major Stream Improvement Projects have taken place on the San Juan in recent years beginning in late 2005.  The projects have been designed to provide better cover for trout and to improve flow in some parts of the river.  More details are available at the link below. 

San Juan Stream Improvement Projects


The San Juan River below Navajo Dam runs through a broad riverbed with a relatively low gradient, often spreading out into multiple channels.   At normal flows of 450 - 500 cfs much of the river is wadeable without depth or strong currents being an issue for strong waders.  

Lake Turnover

As air temperatures cool going from fall to winter, the surface layers of the lake become more dense than the water below them and sink, displacing the water below which moves towards the surface.  The result of this process on the river is that from late December through about March the water on the San Juan in some years is slightly off color.  This is a result of fine clay particulates suspended in the water.  The river fishes well during this period. 

Navajo Lake State Park, NM and Navajo State Park, CO

Navajo Lake State Park is a large NM State Park comprised of Navajo Reservoir and immediate lands around the lake and below the dam.  The park covers 21,000 acres with a lake surface area of over 15,000 acres.  The lake provides fishing for both warm water species and cold water species with marinas at the Pine River Site, Sims Mesa site and near Arboles in southern Colorado.  At the Colorado state line the New Mexico's Navajo Lake State Park ends but Colorado's Navajo State Park begins.  Colorado's Navajo State Park provides year round improved campsites, fishing, hiking trails and a marina.  Facilities for Colorado's Navajo State Park are near Arboles, CO.

Navajo Lake State Park in NM provides improved campsights at the Pine River Site immediately north of the dam off Highway 511 and at Sims Mesa, accessible from from the south via Highway 527, and at Cottonwood Campground a few miles below the dam on the San Juan River.  

Navajo Lake State Park                       Navajo State Park

San Juan River Climate - Temperature and Precipitation
The San Juan has a comfortable climate for fishermen as the highs of summer days are warm but not humid, winter temperatures not so cold as to prevent you from enjoying fishing when properly equipped.  The high desert of the San Juan canyon country has large overnight temperature changes in the range of  20ºF to 30º F.  Moderating breezes are present many days in the afternoon, especially in springtime.  The warmest days of summer are often tempered by thunderstoms which quickly cool the air.  When compared with trout rivers further north the San Juan enjoys a long, steady fishing season as the consistent temperatures from the dam provide consistent Midge hatches in the Quality Water along with Baetis year round.  Air temperatures in the winter are generally above freezing providing several hours of comfortable fishing each winter day.  The San Juan is located at a high altitude with the top of the dam near 6,000 ft and the riverbed below around 5,700 feet.  Sun protection is recommended all year long, especially in warmer months. 

Navajo Dam Weather Forecast

Temperatures generally have overnight lows just below 20º F with highs near 40º.  Precipitation for the month is about 1" with light snows accounting for some of the moisture.  Following the brief snow storms, the sun generally comes out and clears the roads quickly.  There are Midge and baetis hatches in January, fishing is not uncomfortable for those who are properly equipped.  Layering is the best way to keep warm along with appropriate gloves, hats and wading boots large enough for heavy socks.  January is usually the coldest month of the year. 

Temperatures begin to warm slightly with overnight lows in the low 20's and daytime highs in the mid 40's.  As with January, there is moderate moisture some of which comes in the form of snow.  Daytime highs are generally warm enough to melt snow and ice from the roads.  Winter fishing continues in February with both Midge and baetis hatches.  Layering is important again for protection from the elements.

Spring is on the way in March as overnight lows are near 30º F and daytime highs are in the mid 50's.  March brings a little more moisture than January and February, again, some of it may be short lived snow.  The warmer afternoons sometimes bring on seasonal breezes.  A properly equipped fishermen can be comfortable and catch fish - lots of people have great fishing days in March. 

Ovenight temperatures continue to warm with overnight lows in the mid 30's and daytime highs in the mid 60's.  As with March, some afternoons are breezy but overall temperatures are comfortable for fishermen.  April generally has fish moving out of their winter holds in slower water and reoccupying faster water including riffles and runs.  Toward the end of April the Bureau of Reclamation may be starting to progressively release greater flows from Navajo Dam, normally peak flows do not occur until sometime in May.  The moderate amount of precipitation in April is generally in the form of rain. 

Overnight temperatures continue to rise with lows in the mid 40's and daytime highs in the low 70's.  The  flows generally go up in May to about 5,000 cfs.  Flows above 2,000 cfs are generally difficult or dangerous for wading fishermen.  The higher flows often relocate fish to near the banks so the higher flows do not prevent fishermen without boats from being successful, however, fishing with a guide in a drift boat is highly recommended during higher flows as the guides know how to be successful in these conditions.  In addition, not wading the river when it is high is strongly recommended as a safety measure.  Precipitation in May is moderate. 

Both overnight lows and daytime high temperatures continue to increase as summer conditions begin to prevail.  Daytime highs are in the mid 80's with overnight lows in the low 50's.  June is usually the driest month of the year with average June precipitation close to .5".  During June the flows generally start to return to normal with more water being open to wading fishermen toward the middle and end of the month. 

July is the warmest month of the year and also one of the wettest.  Overnight lows are near 60º F and daytime highs average about 90º F.  Afternoon thunderstorms are present along with lightning.  These thunderstorms are generally short in duration and localized, but they can be intense.  Take appropriate precautions when lightning is in the area.  During July the flows are generally returned to normal.  Seasonal trout foods such as Pale Morning Duns, Caddis, terrestrials and Stone Flies may be present on the water in the areas that they inhabit.  Midge and Baetis hatches continue.  To stay comfortable while sitting out thunderstoms waterproof outergarments are recommended.  Fishing jackets made with GoreTex are the most comfortable as they are highly breathable. 

Temperatures begin to cool slightly in August with daytime hights in the upper 80's and overnight lows generally around 60º F.  August is the wettest month of the year, most moisture coming in afternoon and evening thundershowers.  As with July, these thunderstorms can be intense and when there is lightning around, they can be dangerous.  As in July, rain protection can be important to sit out short thunderstorms. 

As days get shorter the temperatures are dropping with September daytime highs averaging a little under 80º F and overnight lows in the low 50's.  September precipitation is in the form of rain and averages about 1".  Fall fishing can be supurb.  As the temperatures begin to come down in the high country of the San Juans, the Aspens begin to turn color.  If you are able to spend a day in the Colorado high country as the leaves are turning you will be well rewarded.

Shorter days and cooler temperatures than September.  Daytime highs are a little below 70º F and overnight lows average just under 40º F.  October precipitation is about 1" in the form of rain with some thunderstorms.  The cooler fall temperatures turn the San Juan valley gold in color as the large cottonwoods adapt to the season.  Fishing continues to be good. 

November fishing is quite beautiful, the year round hatches continue and the summer crowds are gone.  The temperatures are cool but generally not cold with the daytime highs averaging over 50º F.  Overnight lows begin to dip slightly below freezing so this will change a few things for campers. Precipitation in November is about 1" with most of this as rain. 

Temperatures continue to go down in December with overnight lows around 20º F and daytime highs about 40º.  The days are short and the nights are long - but the trout continue to feed.  Midges and Baetis continue to hatch on various parts of the river.  December precipitation is about 1" with mostly rain but some snow is possible.  As with other months, snowstorms in December generally do not produce accumulated snow and ice as the storms are generally short in duration followed by warmer days and sunshine which melts the snow and ice quickly.