HYDROLOGIC ALTERATION OF THE LOWER RIO GRANDE TERMINUS: A QUANTITATIVE ASSESSMENT

The lower Rio Grande is one of several imperilled river reaches in North America. Drought and water withdrawals for agriculture and municipal use are acknowledged as primary sources of riverine degradation. We agree that these are critical components adversely affecting the river but also suggest disruption in the normal flood-pulse cycle of the lower Rio Grande, resulting from impoundment or Falcon Lake and poor management of releases from Falcon Lake Dam, have contributed substantially to decline in ecosystem integrity. We provide statistical evidence and real observations in support of the hypothesis that loss of the natural flood-pulse cycle of the lower Rio Grande has detrimentally affected the riparian ecosystem. Although the presence of adverse effects from disruption of the flood-pulse cycle is intuitive, this is the first report quantifying the degree of alteration in the lower Rio Grande. Copyright (C) 2009 John Wiley & Sons, Ltd.