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Phoenix AMA Surface Water Conditions

Streamflow data, including average seasonal flow, annual flow and other information are shown in Table 8.1-2.  Flood ALERT equipment in the AMA is shown in Table 8.1-3.  New flood warning gages are routinely added to the ALERT network so the current number of stations may be greater.  Reservoir and stockpond data, including maximum storage or maximum surface area, are shown in Table 8.1-4. The location of streamflow gages identified by USGS number, flood ALERT equipment, USGS runoff contours and large reservoirs are shown on Figure 8.1-4A and B.  Descriptions of stream, reservoir and stockpond data sources and methods are found in Volume 1, Appendix A. 

Streamflow Data

  • Refer to Table 8.1-2.
  • Data from 35 stations located at 15 watercourses are shown in the table and on Figure 8.1-4.
  • Average seasonal flow varies and regulated releases from dams on the Salt, Verde, Gila and Agua Fria rivers influence the seasonal flow regime. On other drainages, average seasonal flows are generally greatest in the winter season (January-March). 
  • The largest annual flow recorded in the AMA is 6.1 million acre-feet in 1993 at the Gila River at Estrella Parkway near Goodyear with a contributing drainage area of 45,585 square miles. 

Flood ALERT Equipment

  • Refer to Table 8.1-3.
  • As of October 2005 there are 198 ALERT gages in the Phoenix AMA.

Reservoirs and Stockponds

  • Refer to Table 8.1-4.
  • The AMA contains five large reservoirs.  The largest by far is Lake Pleasant, which is located in the Agua Fria Basin. However, the dam that impounds Lake Pleasant, New Waddell, is located at the AMA boundary.
  • Four reservoirs have recreational purposes.  Other reservoir uses include flood control, hydroelectric power generation, irrigation and water supply.
  • Surface water is stored or could be stored in 41 small reservoirs.
  • There are 711 registered stockponds in the AMA.

Runoff Contour

  • Refer to Figure 8.1-4A and B.
  • Average annual runoff is highest, 1 inch per year or 53.3 acre-feet per square mile, on the northeastern AMA boundary and decreases to 0.1 inches, or five acre-feet per square mile, in the center of the AMA.

Click to view Table 8.1-2

Table 8.1-2 Streamflow Data for the Phoenix AMA

Click to view Table 8.1-3

Table 8.1-3 Flood ALERT Equipment in the Phoenix AMA

Click to view Table 8.1-4

Table 8.1-4 Reservoirs and Stockponds in the Phoenix AMA

Click here for Figure 8.1-4A

Figure 8.1-4A Phoenix AMA East Valley Surface Water Conditions

Click here for Figure 8.1-4B

Figure 8.1-4B Phoenix AMA West Valley Surface Water Conditions


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