05__Draft_PWS_Sources_Sought_1.pdf

PERFORMANCE WORK STATEMENT

Aerial Snow Surveys of Upper Carson, Tahoe, Truckee and San Joaquin Basins

June 2021

1.0 SCOPE

The objective of this contract is to acquire spatial snow depth measurements across the upper portions of the Carson, Tahoe, Truckee, and San Joaquin watersheds and be provided accurate spatial estimates of snow water equivalent and snow albedo. These surveys will be acquired through remote sensing (LiDAR and imaging spectrometer), conducted at periodic or strategic intervals, and may span across accumulation and ablation phases of a winter season. Measurements must be robust to steep terrain, forested areas, and capture the full variability in snow depth. Data acquisition must be able to respond to changing weather, be able to deploy with short notice, and data reporting must allow Reclamation to make reservoir management decisions in near real-time. Snow survey methods must be equivalent to or better than NASA Airborne Snow Observatory methodology. The advances in runoff forecasting made possible by remotely sensed snow surveys creates substantial benefits to water users and implementing environmental commitments and provides broad public benefits such as reduced flood magnitude.

2.0 BACKGROUND

Reclamation’s water operations are highly dependent upon river forecast data. In the Sierra Nevada Mountains, upwards of 70% of the river runoff originates from the snowmelt. On the east side of the Sierra Nevada Mountains, the Carson, Truckee, and Tahoe basins drain to into endorheic basins and supply water for the Newlands Project. On the west side of the Sierras, the San Joaquin watershed above Millerton Lake, impounded by Friant Dam operated by Reclamation, is a high elevation watershed of California’s Sierra Nevada. Annual runoff is highly variable from year to year on both the east and west sides of the Sierras. Over the past decade, the Sierras have faced the both largest drought and the largest flood on record. Management of snowmelt runoff has been challenged by limited forecast accuracy and slow reporting times. Snowmelt directly impacts river forecasts, which are used by Reclamation, and water management decisions by water users and environmental projects.

However, the current forecast products do not accurately predict snowmelt and its impact to river forecasts. Improving snowmelt runoff forecasting results in optimization of water management decisions. Therefore, Reclamation needs improved snowmelt forecasting and river forecasts on both east and west side of the Sierra so that water managers can manage water resource in an environmental and economically sound manner.

NASA’s Jet Proposal Labs (JPL) developed a project called “Airborne Snow Observatory” (ASO) that developed an effective process to estimate snowpack water volume and develop precision snowmelt forecasts. Snow albedo is also measured by ASO, which indicates when snow will melt and runoff into rivers and reservoirs. NASA’s research and development effort ended the in 2019 and completed the Technology Transfer process to a private vendor called the Airborne Snow Observatory Incorporated (ASO Inc.) in late 2019. ASO Inc. has exclusive license to apply the scientific method developed in the NASA’s Airborne Snow Observatory research project. In 2020, San Joaquin River Restoration Project (SJRRP) contracted with ASO for four surveys. Moving forward, both the Lahontan Basin Area Office (LBAO), which oversee the Newlands Project, and SJRRP need to contract with ASO Inc. to collect surveys for their respective basins.

The service provider retains responsibility for all aspects of data acquisition, airspace permission, ensuring that flight operations adhere to any applicable DOI Office of Aviation Service requirements, reporting, and transfer of data.

3.0 REFERENCES

The following list of documents are required in the performance of this contract:

Author

Title

Date

Source

Painter, T. et al., 2016

The Airborne Snow Observatory: Fusion of scanning lidar, imaging spectrometer, and physically based modeling for mapping snow water equivalent and snow albedo

October 2016 Remote Sensing of Environment, Volume 184, Pp. 139-152.

Hedrick, A. et

al. 2018

Direct Insertion of NASA Airborne Snow Observatory- Derived Snow Depth Time Series into the iSnobal Energy Snow Model

October 2018 Water Resources Research,

pp. 8045-8063

Marks D., Domingo J., Susong D., Link T., and Garen D.

A Spatially Distributed Energy Balance Snowmelt Model for Application in Mountain Basins

September 1999 Hydrological Processes, Pp.

1935-1959.

4.0 PERIOD OF PERFORMANCE

The period of performance for this requirement shall be from October 30, 2021 through September 30, 2022.

5.0 TASKS

The contractor shall perform specific tasks for both LBAO and SJRRP. The tasks are defined below.

The tasks assume that the contractor has the snow-off LiDAR datasets for the Carson, Truckee, Tahoe, and San Joaquin basins.

Task 1: LBAO Snow Surveys and Forecast Modeling

Subtask 1.1—Collect Snow Survey Data from the Carson, Truckee, and Tahoe basins

Collect two snow depth data and snow water equivalent data (SWE) and snowpack albedo (reflectivity) across the Carson, Truckee, and Tahoe basins. Surveys will be conducted between February 1, 2022 and June 15, 2022, and if mutually agreeable between parties at other times.

Reclamation will consult with the contractor and set a 15-day target window to accomplish a complete survey, based upon weather and hydrology, which may require multiple flights across multiple days.

This window will be scheduled to start at least 72 hours into the future; the window may be rescheduled or shifted by mutual agreement of both parties. Aerial snow surveys must cover at least 95% of the snow-covered terrain in the Carson, Truckee, and Tahoe basins (See Attachment 1 – Carson, Truckee, and Tahoe Snow Covered Areas).

Subtasks 1.2—Snow Survey Reporting

For each aerial snow survey, which includes calibration to ground-based measurements, the contractor shall provide an electronic report within 72 hours of final flight completion. Calibration will be equivalent to or exceed the methods described in Painter, T. et al. 2016. Receiving the updated snow survey data within 72 hours after the final flight ensures that reservoir operators have the most up-to-date information to guide operational decisions.

Subtask 1.3—Snowmelt/Runoff Modeling and Reporting iSNOBAL model output or equivalent model output will be provided on semi-monthly intervals from February 1, 2022 through June 30, 2022. These will quantify modeled total snowpack depth, density, and snow water equivalent spatially across each watershed and tabulated by 1000’ elevation band.

When aerial snow survey data is available, the model will be updated with measured snow depths.

Model output at operational snow pillow sites will be shown in graphical or tabular means and compared to snow pillow reading. This model will also be used to inform the density field for the conversion of snow depth to snow water equivalent provided in the snow survey reports.

Subtask 1.4—LBAO Project Management and Project Coordination Meetings

Coordinate semi-monthly phone meetings between Reclamation and contractor from January 15, 2022 through June 15, 2022 to consult on survey timing, weather, hydrology, and performance factors.

Task 2: SJRRP Snow Surveys

Subtask 2.1—Collect Snow Survey Data from the San Joaquin Basin

Collect one snow depth data and snow water equivalent data (SWE) and snowpack albedo (reflectivity) across the San Joaquin Watershed above Millerton Lake. Surveys will be conducted between March 15, 2022 and June 15, 2022, and if mutually agreeable between parties at other times. Reclamation will consult with the contractor and set a 15-day target window to accomplish a complete survey, based upon weather and hydrology, which may require multiple flights across multiple days. This window will be scheduled to start at least 72 hours into the future; the window may be rescheduled or shifted by mutual agreement of both parties.

This task does not include mobilization/demobilization of instrumentation and aircraft and associated calibrations and survey preparation as that work will be accomplished under an existing Reclamation contract or alternatively under a non-Federal contract.

The area to be surveyed is depicted in the figure of survey areas (See Attachment 2 – SJRRP Upper Watershed Hydrologic Monitoring Map). The required survey area is shown by the combination of areas A, B, and C. Aerial snow surveys must cover at least 95% of the snow-covered terrain in these bounded survey areas.

Subtasks 2.2—Snow Survey Reporting

For each aerial snow survey, which includes calibration to ground-based measurements, the contractor shall provide an electronic report within 72 hours of final flight completion. Calibration will be equivalent to or exceed the methods described in Painter, T. et al. 2016. Receiving the updated snow survey data within 72 hours after the final flight ensures that reservoir operators have the most up-to-date information to guide operational decisions.

Subtask 2.3—SJRRP Project Management and Project Coordination Meetings

Coordinate semi-monthly phone meetings between Reclamation and contractor from March 1, 2022 through June 15, 2022 to consult on survey timing, weather, hydrology, and performance factors.

6.0 DATA AND REPORTS

The contractor shall provide the following data and reports as follows:

Task #

Description

Content

Format

Medium

Delivery

1.2 Snow survey

report

See Task #2 Deliverables below

Electronic file Contractor’s choice

Via FTP or data sharing portal

1.3 Snow

modeling report

See Task #3 Deliverables below

Electronic file Contractor’s choice

Via email, FTP, or data sharing portal

2.2 Snow survey

report

See Task #2 Deliverables below

Electronic file Contractor’s choice

Via FTP or data sharing portal

7.0 DELIVERABLES

The contractor shall submit the following reports in accordance with paragraph 6.0, “DATA AND

REPORTS”:

• Snow Survey Report (Task #1.2 and 2.2) shall include:

a. Brief narrative of survey acquisition and conditions

b. Snow depth by 1000’ elevation band (table: mean, std deviation or percentiles)

c. Snow water equivalent by 1000’ elevation band (table: mean, std deviation or percentiles, total volume)

d. Tabular data broken down by HUC 10 units, broken down by subwatersheds (as applicable), and aggregated for entire San Joaquin Watershed.

e. 50-meter geoTIFF file of snow depth and snow water equivalent

f. Low resolution image of spatial SWE distribution

g. Low resolution image of spatial snow surface albedo

• Snow Modeling Report (Task #1.3) shall include:

a. iSnobal or equivalent model output

b. Brief narrative of conditions and calibration by any measures

c. Snow depth by 1000’ elevation band (table: mean, std deviation or percentiles)

a. Snow density by 1000’ elevation band (table: mean, std deviation or percentiles)

d. Snow water equivalent by 1000’ elevation band (table: mean, std deviation or percentiles, total volume)

e. Tabular data broken down by HUC 10 units, broken down by subwatersheds (as applicable), and aggregated for entire Watershed.

f. GeoTIFF file of snow depth and snow water equivalent

g. Low resolution image of spatial SWE distribution

h. Low resolution image of snow surface albedo or cold content

8.0 PERFORMANCE REQUIREMENTS SUMMARY

Task

Task Description

Performance Indicator

Performance Standard

Minimum Acceptable Quality

Level

Task 1

1.1 Collect two snow

surveys that include snow depth data, snow water equivalent data, and snow albedo data from aerial survey across Carson, Truckee, and Tahoe Watershed between February 1, 2022 through June 15, 2022.

SD at ≤5 meter resolution, SWE at 50-meter resolution

Coverage of watershed’s snow-covered area at the stated resolution

Capture rate of more than 95% of snow-covered area within prescribed survey area(s)

Complete survey within 15-day window, which may be scheduled with 72 hours-notice

Completion Rate Maximum of one survey not completed within the window when an uninterrupted span of 72 hours of clear skies over the watershed occurs.

Scientific and engineering standard

NASA Airborne Snow Observatory methodology and precision (see 3.0 References)

Equivalent to or better

1.2

Survey reporting. Complete and transmit report within 72 hours if final flight completion

Completion rate Maximum of one report not completed and transmitted within 72 hours of final flight completion

1.3 Snowpack modeling

using iSnobal or equivalent and semi-monthly reporting.

March 1, 2022 through June 30, 2022

Complete modeling update and report, including spatial and tabular data of snow depth, density, and SWE and reference to snow pillows

Completion rate 75% of reports completed and transmitted within ±3 days of semi-monthly interval

1.4 Coordination through

semi-monthly phone meetings. January 15, 2022 through June 15, Consistency of availability for meetings

Minimum fraction of meetings will be scheduled and conducted

75% of scheduled meetings occur, unless otherwise cancelled by mutual agreement

Task 2

2.1 Snow Depth data, Snow Water Equivalent data, and snow albedo data from aerial survey across San Joaquin Watershed. March 15, 2022 through June 15, 2022.

SD ≤5 meter resolution, SWE at 50-meter resolution

Coverage of watershed’s snow-covered area at the stated resolution

Capture of >95% of snow-covered area within prescribed survey area(s)

Complete survey within 15-day window, which may be scheduled with 72 hours-notice

Completion Rate Maximum of one survey not completed within the window when an uninterrupted span of 72 hours of clear skies over the watershed occurs.

Scientific and engineering standard

NASA Airborne Snow Observatory methodology and precision (see 3.0 References)

Equivalent to or better

2.2

Survey reporting. Complete and transmit report within 72 hours if final flight completion

Completion rate Maximum of one report not completed and transmitted within 72 hours of final flight completion

2.3 Coordination through

semi-monthly phone meetings. March 1, 2020 through June 15, Consistency of availability for meetings

Minimum fraction of meetings will be scheduled and conducted

75% of scheduled meetings occur, unless otherwise cancelled by mutual agreement

9.0 ATTACHMENTS

Attachment 1 – Carson, Truckee, and Tahoe Snow Covered Areas Attachment 2 – SJRRP Upper Watershed Hydrologic Monitoring Map

ATTACHMENT 1 - CARSON, TRUCKEE, AND TAHOE SNOW COVERED AREAS

ATTACHMENT 2 – SJRRP UPPER WATERSHED HYDROLOGIC MONITORING MAP