Watershed-Scale Hydrogeologic Analysis and Paleohydrologic Modeling With Applications for Predicting Abandonment of Prehistoric Settlements, Mesa Verde Region, Southwest Colorado

1
Watershed-Scale Hydrogeologic Analysis and
Paleohydrologic Modeling With Applications for
Predicting Abandonment of Prehistoric
Settlements, Mesa Verde Region, Southwest
Colorado

• Kenneth E. Kolm and Schaun M. Smith,
• Washington State University and Colorado School
  of Mines
• Y. Eugene Yan, Argonne National Laboratory
• NSF Biocomplexity Conference
• April 2003

2
ACKNOWLEDGEMENTS National Science Foundation
Biocomplexity Grant 0119981Coupled
Human/Ecosystems Over Long Periods, Mesa Verde
Region Prehispanic Ecodynamics

• Dr. Timothy Kohler PI
• Dr. Kenneth Kolm - Co-PI
• Dr. Robert G. Reynolds - Co-PI
• Dr. Mark Varien - Co-PI

3
RESEARCHPURPOSE AND OBJECTIVES

• Perform hierarchical analysis of environmental
  system, including watershed-scale hydrogeologic
  hydrologic systems.
• Develop conceptual and mathematical models of the
  hydrologic system.

4
RESEARCHPURPOSE AND OBJECTIVES (cont.)

• Model lagged response of water resources to
  historic and prehistoric (AD 600-1300) climatic
  changes and environmental stresses.
• Develop understanding of impacts to prehistoric
  settlements by coupling human and hydrologic
  systems modeling and analysis.

5
Detail of Four-Corners Region and Study Area
6
(No Transcript)
7
Mesa Top Environment
Canyon Rim - K Dakota Burro Canyon Ss/Water
Supply/Gw Discharge
Sleeping Ute Tertiary Intrusion
Sage/Yellow Jacket Settlement Site
Eolian Deposits/Farming/Infiltration/Gw Recharge
8
Upper Canyon Rim Environment
Eolian/Farming/Gw Recharge
K Dakota Burro Canyon SS Aquifer Water
Supply/Gw Discharge/Springs Seeps
Colluvium
J Morrison Units
Settlement/Sage
Alluvium
Pinyon/Juniper Scrub
9
Lower Canyon Environment
Sleeping Ute Tertiary Intrusion
J Morrison Units
McElmo Creek
J Junction Creek Ss
J Entrada Navajo Aquifer
Few Settlements
Pinyon/Juniper Scrub
10
Settlement RuinsHovenweep Towers
11
TWO BROAD HYPOTHESES

• Prehistoric (AD 600-1300) groundwater quantities
  were controlled by long-term lagged
  hydro-geologic response, not by direct climate
  forcing.
• This lagged hydrogeologic response to prehistoric
  climatic changes significantly contributed to
  depopulation of the Mesa Verde region by reducing
  the drinking water supply.

12
SITE-SPECIFIC HYPOTHESES

• As the sole variable, climate forcing is not
  system-limiting. Van West 1994, has shown soil
  moisture was adequate for sustaining agriculture
  during prehistoric time periods.
• Infiltration functions of eolian deposits are not
  system limiting. Size of local recharge areas
  for groundwater subsystems is limiting variable.
• Lagged hydrogeologic response is directly related
  to hydrologic properties of Dakota and Burro
  Canyon SS. Variability of prehistoric water
  supply will not match frequency of climatic
  cycles.

13
RESEARCH APPROACH

• 1). Conceptualize and characterize the modern
  hydrologic system, using integrated,
  multidisciplinary hierarchical systems analysis.
• 2). Develop solid and mathematical models to
  visualize and quantify the modern hydrogeology
  and hydrologic system on a watershed-scale, and
  on selected site-specific areas.
• 3). Test mathematical models by incorporating
  known hydrologic system stresses which occurred
  within historic times.

14
RESEARCH APPROACH (cont.)

• 4). Develop scenarios of the paleohydrologic
  system based on paleoclimate records (such as
  tree ring data) for identifying the relative
  roles of climate and human-induced stresses.
• 5). Compare the dynamics of the paleohydrologic
  system with the cultural activities, population
  shifts, and abandonment of cultural centers.

15
BIOCOMPLEXITY LOGIC DIAGRAM FOR CHARACTERIZING
ECOSYSTEM
Problem Definition Systems Scale Sustainability
Citizen Input
Basic Data Gathering and Preparation Surface,
Geomorphic, and Geologic Characterization
Atmospheric System
Surface Water System and Components Hillsides Cha
nnels Lakes and Reservoirs Valley Bottoms and
Wetlands
Structure and Function Physical Chemical
Citizen Involve-ment
Ground Water System and Components Unsaturated
Zone Saturated Zone Recharge and Discharge
Storage and Movement
Structure and Function Physical Chemical
Structure and Function Physical Chemical Biologica
l
Geomorphologic System
Terrestrial Ecosystem
Aquatic Ecosystem
Socioeconomic System
Citizen Decisions
(after Kolm and Langer, 2000)
Decision Support System
16
Upper Canyon Rim Environment Conceptual Model
Climate Precip/ET
Eolian/infiltration/Gw Recharge
K Dakota Burro Canyon SS Aquifer Water
Supply/Gw Discharge/Springs Seeps
Colluvium
Settlement Location
Alluvium
Pinyon/Juniper Scrub
17
Hovenweep Canyon and SpringConceptual Model
Climate Precip/ET
Mesa Top Infiltration/GwRecharge
Gw Discharge/Springs Seeps Phreatophytes (ET)
K Dakota Burro Canyon Ss Aquifer Gw Flow System
18
General Hydrogeologic Hydrologic System
Conceptual Model
Mesa Top
Canyon Rim
Lower Canyon
19
Distribution of Hydrogeologic Units
20
Preliminary 3-D Block Model Bedrock (w/o
Quaternary)
K Dakota Aquifer
K Mancos Sh
J Junction Creek Ss
Tertiary Intrusion
N Aquifer
J Morrison Units
400 meter resolution
21
Preliminary 3-D Block Model Bedrock
(w/Quaternary)
K Dakota Aquifer
Q Eolian Recharge Zone
K Mancos Sh
J Junction Creek Ss
Tertiary Intrusion
N Aquifer
J Morrison Units
Q Alluvium
400 meter resolution
22
REGIONAL SYSTEM CROSS-SECTIONS
23
REGIONAL SYSTEM CROSS-SECTION
24
REGIONAL SYSTEM CROSS-SECTION
25
REGIONAL SYSTEM CROSS-SECTION
26
(No Transcript)
27
(No Transcript)
28
EXPECTED RESULTS

• Hierarchical Systems Analysis of Watersheds
• - approach transferable to any Colorado Plateau
  watershed
• Couple GMS, Hydrogeologic Solid Block Model, and
  Mathematical Models
• - intigration of systems analysis w/3-D
  hydrogeologic block models, and steady-state
  modern system models
• Paleohydrologic System Mathematical Models
• - series of transient models as snapshots
  through prehistoric time using paleoclimate
  records (tree-ring, paleo-jet streams)
• Correlate groundwater models with locations of
  settlements spatially and temporally

29
SUMMARY OF PROGRESS TO DATE

• Continued analysis of surface, geomorphic,
  geologic and hydrogeologic data on
  watershed-scale.
• Continued development of 3-dimensional
  hydrogeologic solid block models (regional and
  site-specific).
• Continued development of modern hydrologic system
  conceptual models.

30
SUMMARY OF PROGRESS TO DATE (cont.)

• Continued development of modern steady-state
  mathematical groundwater flow system models.
• Conceptualization of prehistoric human
  settlements placed in landscape based on
  hydrologic system analysis.

31
Why Did They Leave?
Lowry Settlements
32
Why Did They Leave?
Hovenweep Tower
Dakota Aquifer
Phreatophytes/Spring
33
Questions ?
Hey, wheres everybody going?