2016 Annual Compliance Report for the 

Bureau of Reclamation’s Central Valley 

Project Long-term Water Transfers (2015-

2024)

U.S. Department of the Interior

Bureau of Reclamation

Mid Pacific Region

Sacramento, California January 2017
Mission Statements

The Department of the Interior protects and manages the Nation’s 

natural resources and cultural heritage; provides scientific and 

other information about those resources; and honors its trust 

responsibilities or special commitments to American Indians, 

Alaska Natives, and affiliated island communities.

The mission of the Bureau of Reclamation is to manage, develop, 

and protect water and related resources in an environmentally and 

economically sound manner in the interest of the American public.
2016 Annual Compliance Report

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Introduction

On June 4, 2015, the U.S. Fish and Wildlife Service (Service) issued the biological opinion,

Reinitiation of Programmatic Formal Consultation for Bureau of Reclamation’s Proposed 

Central Valley Project Long Term Water Transfers (2015-2024) with Potential Effects on the 

Giant Garter Snake within Sacramento Valley, California (2015 BO)(Service reference 

#08ESMF00-2015-F-0116), to the Bureau of Reclamation (Reclamation). The 2015 BO was the 

culmination of formal consultation with Reclamation under section 7 of the Endangered Species 

Act of 1973 (as amended) regarding Central Valley Project Long Term Water Transfers (2014-

2024). This report is submitted to meet the annual reporting requirements contained in Term and 

Condition 4 as proposed by Reclamation and documented in the 2015 BO. Term and Condition 4

is: 

“At the end of each water transfer year, Reclamation will submit to the 

Service a monitoring report that contains the following: (i) maps and GIS 

shape files of all cropland idling or cropland shifting actions that occurred 

within the range of potential transfer activities affected under this 

program; (ii) results of current scientific research and monitoring pertinent 

to water transfer actions; (iii) a discussion of conversation measure 

effectiveness; (iv) maps and GIS shape files indicating where rice was 

grown; (v) results of annual snake monitoring; (vi) snake detections; (vii) 

a cumulative history of the location and extent of crop idling/crop shifting; 

and (viii) report on water districts/sellers participation in voluntary best 

management practices. GIS shape files of the parcels that were fallowed 

will be in projected coordinate system NAD 1983 Zone 10 N. The report 

will be submitted to the Service no later than January 31 following each 

transfer year. Reclamation and the Service will establish annual meetings 

no later than February 28 of each year to discuss the contents and findings 

of the annual report and develop additional conservation measures if 

necessary.”

The following sections provide information on each element required by Term and Condition 4.

I. Acreage and Location of Parcels Idled Under the 2016 Transfers

As documented in a July 11, 2016 memorandum from Reclamation to the Service, there were no 

transfers executed during 2016.

II. Monitoring and New Research 

Monitoring

The USGS conducted research during 2016 in compliance with the 2015 BO. As a result, USGS provided 

Reclamation with preliminary data regarding the “Effects of Rice Idling on Occupancy Dynamics of Giant 

Gartersnakes (Thamnophis gigas) in the Sacramento Valley of California” (study) on December 31, 2016.

The intent of the study is to examine the potential effects of water transfers on the snake and to 

analyze the effectiveness of project conservation measures. Being a multi-year study, most of the 

study objectives won’t be analyzed until several years of data are obtained. Data collected during 
2016 Annual Compliance Report

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the first year will analyze the distribution, occurrence, and detection probability of giant garter

snakes (snake) in relation to several factors. While a final report on the 2016 monitoring efforts 

is not currently available for distribution, some of the information presented is summarized 

below:

 83 sites within the action area were sampled from May through September 2016,

 91 snakes were captured at 51 sites,

 There was evidence indicating a positive correlation between fish and frog presence at a 

site and snake occupancy. 

Results from the first year of the study are promising. However, conclusions regarding 

occupancy dynamics will require several more years of data. Reclamation will forward the final 

report of 2016 monitoring efforts to the Service when it becomes available. In review of the 

preliminary data, there is no indication that water transfers are having unanticipated effects on 

snakes, or that conservation measures associated with the 2015 BO are ineffective.

New Research

1) Reclamation received and reviewed a draft data summary of field observations regarding the 

“Effects of the Relative Availability of Aquatic Habitat (water) on Giant Gartersnake 

(Thamnophis gigas) Demography in the Sacramento Valley, California” from USGS. In review 

of the unpublished data, Reclamation did not identify any new information that would add to or 

change the status of the species there is no indication that water transfers are having 

unanticipated effects on snakes, or that conservation measures associated with the 2015 BO are 

ineffective..

2) Reclamation has located only one new literature source related to GGS:

Halstead BJ, Valcarcel P, Wylie GD, Coates PS, Casazza ML, Rosenberg DK. 2016. Active 

season microhabitat and vegetation selection by giant gartersnakes associated with a restored 

marsh in California. Journal of Fish and Wildlife Management 7(2):397–407; e1944-687X. doi: 

10.3996/042016-JFWM-029

While the habitat focus of the research was restored marsh lands, research efforts did occur near 

rice production and a notable result of the study was that there was a general negative response 

of adult female giant garter snakes to rice. In the discussion of results, aside from rice production 

only providing emergent vegetation habitat for approximately one-third of the snakes active

season, it was suspected that the “high proportion of rice cover might result in underestimation of 

the selection for this habitat type because random locations within a rice field nearly always 

resulted in >75% rice cover.” The study results on the relative likelihood of use of locations 

indicates that a “mosaic of cover and water is likely beneficial” to snakes during the active 

season. Thus, the study findings appear to support the conservation measures detailed in the 2015 

BO, specifically the requirements to maintain adequate water in drains and canals, with 

particular importance placed on those drains that have a mosaic of cover.
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III. Conservation Measures

Reclamation, in compliance with Term and Condition number 2 of the 2015 BO, submitted a 

“Supplement to the Conservation Measures” on December 30, 2015. The “Supplement to the 

Conservation Measures” was prepared by the U.S. Geological Survey (USGS) in the form of a 

Scope of Work, Effects of Rice Idling on Occupancy Dynamics of Giant Gartersnakes 

(Thamnophis gigas) in the Sacramento Valley of California (SOW). Reclamation funded USGS 

to implement this SOW during 2016. For more information on this effort see “Monitoring” 

below. 

During March and April of 2016, Reclamation, in conjunction with USGS and the Service, held 

several informational meetings with water districts and farmers in order to provide information 

and recruit participation of landowners in the rice idling occupancy study. Several additional 

properties were included in the study area through this outreach effort.

No new data on GGS occurrences during 2016 are currently available; however, research 

conducted under various programs should be published in the upcoming months. At the time this 

report is being submitted, the most recent data available would be the current California Natural 

Diversity Database information on GGS.

IV. GGS Detections within the Action Area

No reports of inadvertent GGS detections have been reported to Reclamation during 2016. 

V. Cumulative History of Crop Idling under June 4, 2015 BO

Because there were no transfers executed as part of this program since 2015, Table 1 includes 

some additional information from previous transfers to provide some context for amounts of 

acreage being idled from year to year. Crop idling for transfers occurred in 2009, 2014, and 

2015. During 2014 23,120.3 acres of cropland were idled (USBR 2015). Table 1 also 

summarizes the amount of water made available for transfer and the amount of rice fallowed 

between 2009 and present.

Table 1. Water Transfer Quantities 2009 to 2016 (AF) and Acreage of Rice Fallowed

Water Year Crop Idling, Water 

Made Available 

(AF)

Groundwater 

Substitution, Water 

Made Available (AF)

Acreage of Rice 

Fallowed

2009 21,045 58,881 5,946

2010 0 0 0

2011 0 0 0

2012 No Reclamation 

Water Transfers 

Proposed

No Reclamation 

Water Transfers 

Proposed

No Reclamation Water 

Transfers Proposed

2013 0 31,406 0

2014 40,650 10,289 15,694

2015 134,190 85,853 40,490

2016 0 0 0
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VI. Voluntary Best Management Practices (BMP) Implementation

Reclamation continues to work with water districts participating in idling transfers to determine 

the best path forward for reporting implementation of BMPs. Water districts have reported that 

they strive to follow the BMPs detailed in the “Draft Operation and Maintenance Guidelines for 

Sacramento Valley Water Agencies with Verified GGS Populations” (provided to the Service 

with the 2015 annual report). There are general maintenance practices that water districts 

conduct that are consistent with BMPs. 

VII. References

U.S. Bureau of Reclamation. 2015. Compliance Report; 2015 Water Transfers – Biological 

Opinion 08ESMF00-2014-F-0359. 15 pages.