General Description

Imperial Ponds Conservation Area is located on the Imperial National Wildlife Refuge north of Yuma, Arizona. The conservation area is within a portion of the refuge known as the Martinez Lake Management Unit. This management area is closed to the public and consists of fields, marshes, and backwaters that are managed for waterfowl, marsh birds, native fish, riparian obligate bird species, and other wildlife. The conservation area has three land cover types: (1) backwaters, (2) riparian fields to be planted with cottonwood-willow, and (3) marsh. Ponds Conservation Area is located on Imperial National Wildlife within a portion of the refuge known as the Intensive Management Area.  This management area is closed to the general public and consists of fields, marshes, and ponds that are managed for waterfowl, marsh birds, native fish, riparian obligate bird species, and other wildlife.

Disconnected Backwaters- Imperial Ponds

Six backwaters provide approximately 80 acres of habitat for endangered razorback sucker and bonytail fish species. The backwaters are independently managed to provide a diversity of depths and habitat features, including rip-rap for cover, hummocks for establishment of emergent vegetation, and gravel for spawning substrate. The backwaters now have a water delivery system that is 100 percent well water supplied and is assumed to be completely free of all life stage of nonnative fish. Razorback sucker and bonytail have been stocked into the backwaters.

Riparian - Cottonwood-Willow Forest

An existing 4-acre cottonwood-willow nursery on the refuge will expand by 34 acres on soils excavated from the backwaters. The excavated material raised the fields 3 to 4 feet making them suitable for planting with cottonwood and willow. The additional forested area, interspersed with the backwaters and other fields managed for waterfowl, should create a vegetation mix that makes this an ideal site for attracting LCR MSCP covered species. Field leveling and irrigation system installation for the new area was completed in 2008. The fields are currently managed with a cover crop. Tree planting is scheduled for 2019.

Marsh– Field 18

A 12-acre marsh unit was created on the southeast corner of the intensive management area in 2008, and has attracted California black rail, Yuma clapper rail, and western least bittern - three LCR MSCP covered marsh bird species.

A fact sheet for this conservation area can be found here. Technical reports for this conservation area can be found here.

Updated January 7, 2020

Imperial National Wildlife Refuge is located in Yuma County, Arizona about 40 miles northeast of Yuma, Arizona. The Refuge manages land in both the states of California and Arizona. The Imperial Ponds Conservation Area is located to the east of the Colorado River at River Mile 59.The Conservation Area is located on a portion of Imperial National Wildlife Refuge that remains closed to the general public to minimize disruption to wildlife. Information on Imperial National Wildlife Refuge, including location, purpose, and regulations, can be found on their website at this link.

For specific information on the Conservation Area, please contact Terry Murphy, Restoration Group Manager, at tmurphy@usbr.gov.

The image below shows a close up of the conservation area.

Each Conservation Area targets certain LCR MSCP covered and evaluation species habitats. Below, on the left, is a list of the LCR MSCP species in which habitat will be targeted for creation for this particular conservation area. To the right is a list of LCR MSCP species that, through monitoring, have been found utilizing the conservation area.

Fisheries

Water quality monitoring is conducted throughout the backwaters both daily and quarterly. Daily monitoring occurs at a single location in each backwater using a submersible multi-parameter water quality instrument. Daily parameters measured include: temperature, conductivity, dissolved oxygen (DO), and pH. Quarterly data is collected using a handheld multi-parameter water quality instrument. Vertical profiles are taken at three pre-determined points throughout each pond. Quarterly parameters measured include: temperature, conductivity, DO, and pH.

The backwaters have been recently renovated to remove all nonnative fish. The backwaters are stocked with razorback sucker and bonytail. Stocking fish management and monitoring will continue. Fishery management and research within the ponds will consist of conducting population estimates for razorback sucker and bonytail marked with a passive integrated transponder (PIT) tag for individual identification and genetic management of recruiting population.

Marsh Birds

Presence/absence marsh bird surveys will be conducted in March, April, and May at previously established points within Field 18.

Riparian Management

The 34 acres have been stabilized with a cover crop to facilitate leaching of the saline soils prior to planting with cottonwood and willow. Fertilizing of the riparian fields will continue during the fall and spring, with a high nitrogen fertilizer and humic acid, to help mobilize salts and facilitate salt flushing. The tentative schedule for tree planting is 2019.

Acreage Map

This map shows the acreage for this area. You can click on the map for a larger view.

This gallery includes photos of this conservation area. If you require larger photos, please contact our webmaster Michelle Reilly at mreilly@usbr.gov.