The Rillito River (;

Spanish Spanish might refer to: * Items from or related to Spain: **Spaniards are a nation and ethnic group indigenous to Spain **Spanish language, spoken in Spain and many Latin American countries **Spanish cuisine Other places * Spanish, Ontario, Can ...

"Little River") is a river in Pima County, Arizona. It flows from east to west across the northern boundary of the City of

Tucson , "(at the) base of the black ill , nicknames = "The Old Pueblo", "Optics Valley", "America's biggest small town" , image_map = , mapsize = 260px , map_caption = Interactive map ...

from the confluence of Tanque Verde Creek and Pantano Wash to the Santa Cruz River away. The

Rillito River Park Rillito River Park is a 12-mile-long linear park in Tucson, Arizona, that runs along the north and south banks of the Rillito River from Interstate 10 to North Craycroft Road. The park is part of The Loop, a network of linear parks serving Tucs ...

runs along the north and south banks of the river from Interstate 10 to North Craycroft Road.

History

Prior to colonization by European settlers, much of the Santa Cruz valley was filled with

riparian A riparian zone or riparian area is the interface between land and a river or stream. Riparian is also the proper nomenclature for one of the terrestrial biomes of the Earth. Plant habitats and communities along the river margins and banks a ...

habitats, including numerous zones along the banks of the Rillito River. As recently as the late 19th century, the river was a

perennial stream A perennial stream is a stream that has continuous flow of surface water throughout the year in at least parts of its catchment during seasons of normal rainfall, Water Supply Paper 494. as opposed to one whose flow is intermittent. In the abse ...

lined with trees and dense vegetation such as cottonwoods, willows, and mesquites. However, due to increased pumping of groundwater for irrigation projects to support agriculture and urban development, the river eventually dried up and much of the riparian habitat was lost by the mid-20th century. The loss of vegetation led to increased erosion of the

river banks In geography, a bank is the land alongside a body of water. Different structures are referred to as ''banks'' in different fields of geography, as follows. In limnology (the study of inland waters), a stream bank or river bank is the terrai ...

during flood events, which in turn led to a widening and straightening of the river channel. Today, the Rillito is an

ephemeral Ephemerality (from the Greek word , meaning 'lasting only one day') is the concept of things being transitory, existing only briefly. Academically, the term ephemeral constitutionally describes a diverse assortment of things and experiences, fr ...

river that carries water only during floods or in response to snowmelt. In the late 20th century, as a

flood control Flood control methods are used to reduce or prevent the detrimental effects of flood waters."Flood Control", MSN Encarta, 2008 (see below: Further reading). Flood relief methods are used to reduce the effects of flood waters or high water level ...

measure, many segments of the channel's banks were stabilized using

soil cement Soil cement is a construction material, a mix of pulverized natural soil with small amount of portland cement and water, usually processed in a tumbler, compacted to high density. Hard, semi-rigid durable material is formed by hydration of the ce ...

to reduce erosion and prevent the water from overflowing the banks and damaging property.

References

{{authority control Rivers of Arizona Rivers of Pima County, Arizona Sonoran Desert Santa Cruz River (Arizona)