Riparian area changes in greenness and water use on the Lower Colorado River in the USA from 2000-2020
Remote Sensing
Links
- More information: Publisher Index Page (via DOI)
- Data Release: USGS data release - Colorado River Project: A compilation of vegetation indices, phenology assessment metrics, estimates of evapotranspiration and change maps for five reaches between Hoover and Morelos Dams on the Lower Colorado River, for nearly the last two decades
- Open Access Version: Publisher Index Page
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Abstract
Declines in riparian ecosystem greenness and water use have been observed in the delta of the Lower Colorado River (LCR) since 2000. The purpose of our case study was to measure these metrics on the U.S. side of the border between Hoover and Morelos Dams to see if declining greenness was unique to the portion of the river in Mexico. In this case study, five riparian reaches of the LCR from Hoover to Morelos Dam since 2000 were studied to evaluate trends in riparian ecosystem health. We measure these riparian woodlands using remotely sensed measurements of the two-band Enhanced Vegetation Index (EVI2; a proxy for greenness); daily evapotranspiration (ET; mmd−1) using EVI2 (ET(EVI2)); and an annualized ET based on EVI2, the Phenology Assessment Metric (PAM ET), an annualized ET using Landsat time-series. A key finding is that riparian health and its water use has been in decline since 2000 on the U.S. portion of the LCR, depicting a loss of green vegetation over the last two decades. EVI2 results show a decline of −13.83%, while average daily ET(EVI2) between the first and last decade had a decrease of over 1 mmd−1 (−27.30%) and the respective average PAM ET losses were 170.91 mmyr−1 (−17.95%). The difference between the first and last five-year periods, 2000–2005 and 2016–2020, showed the largest decrease in daily ET(EVI) of 1.24 mmd−1 (−32.61%). These declines come from a loss in healthy, green, riparian plant-cover, not a change in plant water use efficiency nor efficient use of managed water resources. Our results suggest further deterioration of biodiversity, wildlife habitat and other key ecosystem services on the U.S. portion of the LCR.
Suggested Citation
Nagler, P.L., Barreto-Muñoz, A., Borujeni, S.C., Nouri, H., Jarchow, C., and Didan, K., 2021, Riparian area changes in greenness and water use on the Lower Colorado River in the USA from 2000-2020: Remote Sensing, v. 13, no. 7, 1332, 48 p.; Data Release, https://doi.org/10.3390/rs13071332.
Study Area
| Publication type | Article |
|---|---|
| Publication Subtype | Journal Article |
| Title | Riparian area changes in greenness and water use on the Lower Colorado River in the USA from 2000-2020 |
| Series title | Remote Sensing |
| DOI | 10.3390/rs13071332 |
| Volume | 13 |
| Issue | 7 |
| Publication Date | March 31, 2021 |
| Year Published | 2021 |
| Language | English |
| Publisher | MDPI |
| Contributing office(s) | Southwest Biological Science Center |
| Description | 1332, 48 p.; Data Release |
| Country | United States |
| State | Arizona, California |
| Other Geospatial | Lower Colorado River |