by Steve Sanchez, Bureau of Land Management
The Bureau of Land Management uses several methods for riparian assessment or evaluation. They include “Riparian Area Management, Inventory and Monitoring Riparian Areas, Technical Report TR 1737-3”, “Riparian Area Management, A User Guide to Assessing Proper Functioning Condition and Supporting Science for Lotic Areas, TR 1737-15”, “Riparian Area Management, Process for Assessing Proper Functioning Condition, TR 1373-9”. The San Luis Valley Saguache and La Jara Field Offices have selected a two-tiered approach that includes both extensive and intensive inventory.
The extensive inventory is used to identify, characterize and classify riparian sites. The approach contained in “Riparian Area Management, Process for Assessing Proper Functioning Condition” mentioned above is used for extensive inventories. Based on resource values and site characteristics, a decision is made whether or not to conduct an intensive inventory. Sites with low resource values in acceptable condition usually result in continued monitoring, but no intensive inventory. However, an intensive inventory is usually performed on sites with high resource values or unacceptable conditions. Using intensive inventory only is such situations utilizes limited staff time most effectively.
With the “Process for Assessing Proper Functioning Condition” approach, data are collected on hydrology, vegetation, and erosion / deposition attributes. From these monitoring data, the functionality of the riparian is determined to be in proper functioning condition (PFC), non-functional (NF), or functional-at-risk (FAR). Determinations of causative factors of non-functional or functional-at-risk results are made in the field. Mitigation decisions are made to eliminate or reduce causative factors. Examples of mitigation include relocating a road away from an adjacent streamside, creating a riparian pasture, or installing a culvert.
In 1998, the Saguache and La Jara Field Offices committed to inventory and assess the proper functioning condition of all lotic riparian habitats managed by the BLM in the San Luis Valley within a 4-year period. Happily, this task was completed by August 2000, primarily with the support of a trained and dedicated volunteers, seasonal support, local range permittees, and a permanent employee interdisciplinary team.
Thus far, we have assessed 103 streams, 138 stream reaches, 235 miles and approximately 818 acres. Additionally, over 75 “dryparians” were evaluated but not assessed. The number of stream reaches in six categories is provided below.
Nearly two-thirds (64%) of stream reaches studied are in proper functioning condition. Only 11 reaches (8%) were in non-functioning condition. The assessment data are being used to locate potential reference streams, identify major management problems, evaluate land health standards, and identify those streams where quantitative data may need to be collected.
|* the 4 unknown riparian areas were either newly discovered areas due to a land status change or were originally thought to be ephemeral.