Status of climate and water resources at Montezuma Castle and Tuzigoot national monuments: Water year 2017

Gwilliam, Evan; Goodrum, Gregory; Raymond, Kara; Palacios, Laura

Climate and hydrology dramatically shape ecosystem structure and function, particularly in arid and semi-arid ecosystems. Understanding changes in climate and water resources is central to assessing the condition of park biota as well as key cultural resources. This document summarizes climate and water resource conditions for water year (WY) 2017 for Montezuma Castle and Tuzigoot national monuments, two small National Park Service units in central Arizona. Overall annual precipitation was 117% of normal for Montezuma Castle National Monument (NM) and 129% of normal for Tuzigoot NM. Mean monthly temperatures tended to be warmer than normal and there were substantially fewer extremely cold days. However, the reconnaissance drought index for Tuzigoot NM indicates a recovery over the past three years from a regional drought that began in 2000; while an initial recovery began at Mon-ezuma Castle NM In WY2017. The Sonoran Desert Network (SODN) monitors three springs at Montezuma Castle and Tuzigoot national monuments, one at each unit. At Montezuma Castle NM are Expansion Spring (Castle unit) and Montezuma Well (Well unit). At Tuzigoot NM is Shea Spring. The full complement of SODN springs monitoring (site condition, water quantity, and water quality) is done only at Expansion and Shea springs. In WY2017, both springs had surface water present, were flowing, and showed little sign of change or disturbance. The network also monitors one stream at each unit of Montezuma Castle and Tuzigoot na-tional monuments. At Montezuma Castle NM, index sites are on Beaver Creek (Castle unit) and Wet Beaver Creek (Well unit). At Tuzigoot NM, the network monitors the Verde River. SODN staff sampled each index site quarterly during WY2017, collecting data on water quantity, water quality, and macroinvertebrates. At Wet Beaver Creek, mean daily discharge during WY2017 was 44.6 cubic feet per second (cfs)—well above the 56-year gauge record mean of 30.3 cfs. However, during the ecologically important spring snowmelt period (typically mid-January to mid-May), mean daily discharge was below or approaching the lower 5th percentile. Recorded flow for the Verde River was either at or below the 25th percentile for most of the year. There were five exceedances of state water quality standards during WY2017, resulting in a 98.1% overall compliance with state standards across the three units. Four of the exceedances were at the Beaver Creek index site: two for total arsenic, one for E. coli, and one for dissolved oxygen. The other was for total arsenic at the Wet Beaver Creek index site. SODN urges park managers to continue to limit public access to the streams and water bodies, and to provide guidance and personal protective equipment to employees who need to come in contact with the water. No one should ever drink or otherwise ingest un-treated stream water from these sites. None of the WY2017 Arizona indices of biotic integrity calculated from macroinvertebrate data was in the “attaining” range for any site.

Status of climate and water resources at Montezuma Castle and Tuzigoot national monuments: Water year 2017

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