The IID’s Pupfish refugium is located at the IID Fish Hatchery complex north of Villa Road in El Centro, California.  The facility, completed in December 2010, consists of two small ponds connected by a shallow channel.  The channel includes a control structure that will allow either pond to be isolated for maintenance or to capture fish.  The ponds are lined with a clay substrate that is covered with pea gravel.  Each pond has a separate regulated inlet and outlet and can be operated separately if necessary.  

In late 2014, the IID worked with USFWS and CDFW to begin the process for stocking of pupfish in the summer of 2015. Fence and netting were discussed to deter wildlife from accessing the ponds.

In 2015, the IID installed fencing and netting around the two ponds and filled both with water. The Biological Control unit has been monitoring dissolved oxygen and temperature daily as part of their monitoring efforts of the facility.

Pupfish were successfully introduced to the refugium in 2016 and monitoring in 2017 captured over 1000 pupfish within the two ponds.

The four-year quarterly sampling study to characterize physiochemical conditions in 29 agricultural drains flowing directly into the Salton Sea was completed in 2009 by the USGS Western Fisheries Center and completed the report; Final Report: Baseline Selenium Monitoring of Agricultural Drains Operated by the Imperial Irrigation District in the Salton Sea Basin (USGS- Open File Report 2010-1064) in 2010. The surrogate species study was also completed in 2010 and identified sailfin mollies as a suitable surrogate for approximating selenium concentrations in desert pupfish. These reports are available on the IID web page. The IID is conducting on-going monitoring of selenium levels in select drains that connect to the Salton Sea.

Vegetation and Seepage monitoring: The IID regularly surveys vegetation communities that naturally occur around selected seepage recovery pumps. This allows for monitoring of any stress to riparian areas and data collection and accounting.

The Bureau of Reclamation (Reclamation) report Southwestern Willow Flycatcher Breeding Habitat Evaluation at the Salton Sea (Olson August, 2008) identified a number of sites that contained potential southwestern willow flycatcher habitat within the HCP covered area. Several of the sites identified, such as the Wister Unit and Finney Ramer, are areas managed by others for wildlife habitat and will not require additional monitoring by IID. A preliminary plan for monitoring the identified southwestern willow flycatcher potential habitat sites was developed and reviewed by the IT. The New and Alamo river deltas were monitored in 2011 and 2012 and showed no significant vegetation changes. Minimal vegetation clearing occurred in 2013 to facilitate the design of Species Conservation Habitat, the area was evaluated for Covered Species prior to the vegetation clearing event. IID did not impact Southwestern willow flycatcher habitat in 2014Or 2015. Starting in 2016, each site was visited several times from April 15th through May 15th and surveyed using taped breeding calls.

The final report for the BUOW census effort; Burrowing Owl Population Size in Imperial Valley California:  Survey and Sampling Methodologies for Estimation (Bloom Biological - 2009), was submitted and accepted by the IT in 2009.  Using protocols developed in the pilot study (Bloom Biological -2006), the Service Area was divided into 274 survey grids.  After completing a three-replicate survey of all of the grids, a BUOW population size for 2007 (4,879 male territories) and 2008 (3,557 male owl territories) was determined. 

A modified BUOW “mark-recapture” protocol was used for a subsampling study in 2011 and 2012. The population estimation model stratified all 274 survey grids into low, medium and high densities (based on the Bloom Biological data). 

IID Environmental Specialists or biologists use the location sheets and canal cut-out schedule to regularly survey areas of potential impact for burrowing owls on a year-round basis. In addition to monitoring efforts, IID Environmental specialists conduct a public outreach program in local elementary schools. This program includes an art contest based on Burrowing owls and other desert species. The winners are published on-line and in print through IV Alive! Magazine.

The Managed Marsh Complex is located at the English Road site, bounded by Highway 111 on the east and English Road on the west.  McDonald Rd (O Lateral) is the southern boundary and Hazard Road (P Lateral) is the boundary to the north. The Supplement to the IID Water Conservation and Transfer Project EIR/EIS for the Managed Marsh Complex (June 2008) evaluated a series of locations for the Managed Marsh and identified the English Road site as the preferred alternative. 

Phase I was completed in October, 2009. Phase I consists of three types of constructed habitat (desert riparian, emergent wetland and scrub-shrub bosque) designed to mimic the habitat types identified in the drain vegetation survey. Phase I is approximately 375 acres; with approximately 325 acres of Marsh habitat (open water and emergent vegetation) and 50 acres on non-emergent habitat (mesic herbaceous and woody vegetation).

Phase II was completed in December 2014. Phase II consists of approximately 360 acres; with approximately 321 acres of emergent wetland and 38 acres of desert riparian habitat. Changes from the Phase I design included larger cells with less berms, wider berms and more space to the lateral and drain to facilitate maintenance.

Portions of the east and west buffer areas of the Managed Marsh Complex Phase I and II were planted with mesquite trees and are designed to mitigate for permanent impacts to Native Tree habitat.

IID has completed construction of Phase III of the marsh complex and as of December 2021, is planting trees and flooding to create riparian habitat for wading and marsh birds.

Marsh Bird Surveys:

The IID conducts yearly marsh bird call-back surveys using recorded bird calls and a protocol created by USFWS; as well as year-round passive observation surveys. These surveys allow the IID to monitor and collect data on avian and mammalian usage of the marsh complex.

Numerous species were observed; but American coot (Fulica americana), common moorhen (Gallinula chloropus cachinnans) and pied-billed grebe (Podilymbus podiceps) were the dominant species. Pied-billed grebes were observed nesting with common moorhen, Sora, and Ridgway rail; juveniles of each species were also observed. Other water birds that were frequently identified included mallard (Anas platyrhynchos), cinnamon teal (Anas cyanoptera septentrionalium), and ruddy duck (Oxyura jamaicensis rubida). Mallards were observed with juveniles at the marsh, indicating the continued use of the marsh for nesting. The Ruddy Duck and Canvasback populations and marsh usage have grown significantly since 2018; possibly due to increased open water areas and healthier fish populations.

The population and diversity of birds, including some of the more cryptic marsh birds did not significantly increase in 2019 with American bittern (Botaurus lentiginosus), least bittern (Ixobrychus exilis), and Green Heron (Butorides virescens) identified during the monthly IID avian surveys. Several sightings and vocalizations of Yuma Ridgway rail (Rallus obsoletus yumanensis), Sora (Porzana Carolina) and Virginia rail (Rallus limicola) were noted in the past year.

Passerine birds identified at the marsh included: marsh wren (Cistothorus palustris aestuarinus), red-winged blackbird (Agelaius phoeniceus sonoriensis), yellow-headed blackbird (Xanthocephalus xanthocephalus), black phoebe (Sayornis nigricans semiatra), Tree Swallow (Tachycineta bicolor), and Mourning dove (Zenaida macroura). Unique passerine observations in Phase I included a few loggerhead shrikes and a belted kingfisher.

Phase II continues to provide shorebird habitat with shallow water in the cells. American Avocet (Recurvirostra americana), Black-necked Stilts (Himantopus mexicanus) and Kildeer (Charadrius vociferus) are the most common shorebirds noted.