BLM-MT, Soil Moisture Monitoring Grant, Montana State Office

Increasingly rapid changes to Montana⿿s climate have been observed over the last 55 years, producing more variable and poorly understood impacts to the natural resources on which many Montanans rely. For example, average spring and winter temperatures have increased ~ 4° F and 3° F, correspondingly, impacting important variables to resource managers, such as: the time and duration of streamflow, forage production, shifts in plant communities, and the timing of green-up and senescence of forage for wildlife and livestock.

These climactic changes are expected to continue, with average annual temperatures projected to increase an additional 5° F over the next 30 years, with the greatest seasonal increase in the summer, when average temperatures are projected to jump by more than 7° F. While average annual precipitation is expected to increase, it⿿s predicted to arrive in fewer and more severe storms, as well as through a reduction in summer storms and an increase in winter and spring events. Simultaneously, more frequent and severe droughts are expected. These changes could stress native ecosystems, threaten water resources, and require mitigation to ensure that desired resource values are maintained.

To effectively respond to climate change/drought and the corresponding ecosystem responses, data that relates available water resources to management actions is needed. In Montana, an expansion of the existing soil moisture monitoring network represents an obvious opportunity to the public. This is because soil moisture is one of the major controls on the structure, function, and diversity in ecosystems; is involved in a number of feedbacks at the local, regional and global scales; and plays a major role in climate-change projections. However, existing data sources are limited/non-existent in many locations, requiring individuals to rely on remotely sensed estimates with coarse resolutions and from datasets that may be lacking local calibration.

The recipient will perform a spatial analysis of existing data sources and expected heterogeneity to stratify the landscape and identify soil moisture data gaps within the first year of the agreement. Within the data gaps, the recipient will work with the BLM over the life of the agreement to prioritize and establish monitoring stations in watersheds with high densities of BLM ownership. The recipient will equip most, if not all, monitoring stations to transmit the data in near real-time to a centralized database that is managed by the Montana Climate Office (MCO). Although soil moisture measurements from the rooting zones of native plant communities will be the primary samples, additional sensors (i.e. NDVI sensors) may be included if the BLM & recipient agree that the resulting information aligns with the aforementioned objectives.
Monitoring stations can be located on both public and private lands. However, if they are located on non-BLM lands, any access agreements will permit BLM staff to access the immediate location of the monitoring stations for purposes of maintainance and supplemental data collection.

The recipient will make efforts to integrate the point-scale measurements with spatially continuous datasets that may be usefull for drought management. For example, in situ measurements could be used to improve estimates of the fraction of reference ET to develop a more accurate Evaporative Demand Drougt Index (EDDI). Another opportunity is to use the recently developed in-situ NDVI sensors, combined with soil moisture sensors and measurements of plant vigor and production, to: (1) evaluate uncertainty in VegDRI, and (2) correlate VegDRI to plant condtion/growth metrics that are important to range management during periods of drought.

Objectives: Objectives are aligned with Goal 1 (Data Collection and Integration) & Goal 3 (Drought Planning and Capacity Building) detailed in the Federal Action Plan of the National Drought Resiliency Partnership (2016). Specifically, the objectives are as follows:

1) Provide data needed to optimize land management decisions and adaptively respond to rapidly changing conditions assosciated with climate change and drought. Adding soil moisture sensors to areas that currently lack representation in the existing monitoring network will improve the ability of nearby land managersâ¿¿ to align permitted activities that are directly and/or indirectly impacted by soil moisture (i.e. vegetation treatments, livestock grazing, mine reclaimation, etc.) with existing resource conditions. This will improve adaptive management efforts designed to ensure sustained yield of the resources, which is expected to be increasingly complicated by climate change and the associated feedbacks linked to the natural environement.
2) Integrate the point-scale measurements with spatially continuous datasets derived from remote sensing or other empirical relationships to improve the accuracy and availability of existing and/or new datasets that require soil moisture as an input. The point estimates of soil moisture have high accuracy, precision, and temporal resolution and can be combined with coarser, but spatially continuos datasets to locally calibrate them, as well as determine the uncertainty in the estimates. Combining in situ measurements and remotely sensed estimates of soil moisture, or soil moisture related metrics, will improve the accuracy and availability of data, especially in areas with high heterogeneity or in remote locations that may lack monitoring stations.
3) Coordinate with state and federal partners across Montana to create a single database with standardized data collection, Qa/Qc, and data management. Standardizing the collection and management of soil moisture data, as well as collocating it with data collected by other partners, will improve the accuracy and spatial representation of the dataset. This will increase the utility of the data to end users, as it will be more easily accessible, analyzed, and integrated with external projects and research.

Public Benefit: The public will directly benefit, as the monitoring data will inform all interested parties on the soil moisture conditions across the state, improving land managersâ¿¿ability to adjust their management in response to changing conditons. This is especially important to members of Montanaâ¿¿s large agricultural community.
The public will indirectly benefit from the improvement/development of gridded soil moisture/soil moisture related datasets that are made possible through the incorporation of the point-scale measurements funded by this project. Lastly, the soil moisture data will provide valuable insight to hydrologic changes associated with drought and climate change, supporting research that will further societyâ¿¿s understanding of the impacts of climate change in Montana.