Background and History of the “Tres Rios”

Imagine thinking of the Valley of the Sun as the “Valley of the Three Rivers.” It gives a completely different feel to our 2008-01-11-0019-great-blue-heron-az-phoenix-tres-rios-wetlands-lcommunity doesn’t it? When people first settled in the valley, it was the water that drew them here. Before Phoenix was a city and Arizona was a state, the Salt and Gila rivers flowed freely through the Valley of the Sun. Those waters nourished animal and plant life along the rivers’ banks and created a rich natural environment.

When the Salt River was dammed in the early 1900s, life in the Valley changed. Farmers had a reliable supply of water, aiding the economy in the little towns of Phoenix, Tempe, Mesa, Scottsdale and Glendale. However, the river channel changed to a dry river bed – now recharged by wastewater treatment plants or excess irrigation flow.

But, have you seen the Gila River lately – there are still lush riparian areas – especially in the “Three Rivers area where the Salt and Agua Fria Rivers join the Gila just west of Phoenix. Here you will find the Baseline and Meridian Wildlife Area (B&M Wildlife Area), the river frontage of the Estrella Mountain Regional Park, and more recently the Tres Rios River Restoration Project. The river here is filled with natural flow, ground water and yes, water from the wastewater treatment plants – year-round! It is an incredible spot in the metro area. So, did you know we have an urban Wildlife Area? The B&M Wildlife Area is a property managed by the Arizona Game and Fish Department and yes, right here in our backyard this is a piece of the Gila River that has been set-aside for wildlife.

P3110071RPS_0You will discover that wildlife was not the only fascinating aspect of this river system – the history of our West Valley community is amazing as well! B&M stands for Baseline and Meridian which are mapping terminology and relate to Monument Hill which stands above the confluence of these rivers. It was here in 1865 that it became designated by the Astronomical Survey as Arizona’s “Initial Point”, defining the zero point of the grid that is our Township, Range and Section mapping system. Interestingly two teams selected the spot, first a team from the Mexican Boundary Commission and then by the American team. What does this mean? This is the reference point from where the rest of Arizona is surveyed. Baseline Road is actually the east-west baseline and 115 Avenue (Now Avondale Blvd.) is the north-south meridian.

Today, Monument Hill is used by ISM Raceway (formerly Phoenix International Raceway). Heading south on Avondale Boulevard from I-10 you approach a bridge across the Gila River. If you slow down on the bridge, you will see ISM Raceway to the south and the Gila River below. The river bottom is teaming with life and the when a race is on the raceway – it is also. It is again incredible to see these two areas so close together. ISM Raceway has been a good neighbor and a proud sponsor of the Tres Rios Nature and Earth Festival over the years.

This area is home to abundant wildlife, boasting over 150 species of birds, not to mention mammals, fish, reptiles, and amphibians.

All this in our backyard!

Explore with us!
The Festival is an exciting opportunity for the whole family to learn about the amazing wildlife habitat and history of these systems. Come celebrate the rich heritage and natural beauty of the Gila, Salt and Agua Fria Rivers.

View a story Channel 3 did on the area
View a video that talks about the 3 rivers and the festival