PUB00108

• Year: 1986
• Title: St. Vrain Basin Reconnaissance Study
• CWCB Section: Administration
• Author: Colorado Water Resources and Power Development Authority
• Description: Extensive study for future study and development toward meeting the water-related needs of residents with the St. Vrain Basin
• Publications - Doc Type: Brochure

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CHAPTER II I
HYDROLOGY AND WATER RIGHTS

A. Introduction

This chapter describes the surface and groundwater hydrology of the
St. Vrain Basin. Also included is a description of trans-Basin imports to the
St. Vrain Basin, a discussion of water administration and management and a
summary of water rights in the Basin.

B. Surface Water Hydrology
1. General

St. Vrain Creek has a total
fluence with the South Platte River.
drainage area is from Boulder Creek,
which has a drainage area of 496 sq mi.

The St. Vrain Basin is typical of South Platte River tributaries in
Colorado. The Basin has an eastern aspect, wi th elevat ions ranging from
approximately 4700 feet at the South Platte River to above 13000 feet along
the Continental Divide. Precipitation generally increases with elevation;
snowfall is the main source of runoff to the St. Vrain Basin. The St. Vrain
Basin annually contributes a net 156,000 ac-ft, on the average, to the South
Platte River. This volume is the gaged f low at the mouth, and includes the
effect of trans-Basin imports and depletions caused by irrigated agriculture
and municipal and industrial water uses. Trans-Basin imports are discussed
later in this chapter, and water uses are discussed in Chapter IV.

drainage area of 976 sq mi at its con-
A significant portion of the total
a major tributary to St. Vrain Creek,

The main tributaries of St. Vrain Creek wi thin the Study Area are
the North, South and Middle St. Vrain creeks and Left Hand Creek. Locations
of U.S. Geological Survey (USGS) stream gaging stations are shown in Fig. 111-1
and they are described in the fol lowing paragraphs. Data from those stations
are shown in Table 111-1.

2. North St. Vrain Creek

North St. Vrain Creek, which rises in the high mountains west of
Allenspark, has a drainage area of 127 sq mi, ranging in elevation from
5300 feet at Lyons, to 14250 feet at Longs Peak. USGS Stream Gaging Stat ion
7220, located 4 mi les west of Lyons, operated from 1926 to 1953. In addition
to depletions resulting from irrigation of a reported 300 acres above the
gage, flows reported in Table 111-1 at this gage were partly regulated by
several small reservoirs.