204058 GRA Karst

Sensitive Species and Karstic Waters: 

Sensitive Species and Karstic Waters New Frontiers in Karst Hydrogeology Shawn Chartrand, Balance Hydrologics Barry Hecht, Balance Hydrologics

Take Home Points: 

Carbonates occur throughout California The drainage and chemical characteristics of Karst landscapes and waters are unique Karst landscapes and waters support a variety of ‘sensitive species’, and generally in ways which differ from other ground water environments Take Home Points

Presentation Focus: 

Three characteristics of Karst systems and the ways in which these characteristics benefit and also challenge ‘sensitive species’, their habitats and general watershed planning exercises: baseflows hydrochemistry conduit or tube flow Demonstrate how these characteristics impact ‘sensitive species’ by examining three recently completed projects in the Santa Cruz Mountains Presentation Focus

Slide4: 

Location of Project Sites

General Considerations of Karst in California: 

Carbonates outcrop throughout California species which have evolved in karst landscapes are dependent upon karst drainage California lacks regulations specific to how karst landscapes are to be managed development and water supply, habitat protection, and stormwater management (stormflows and sediment), but Responsibility lies with the project Hydrogeologist General Considerations of Karst in California

Skyline Quarryrole of baseflows in habitat planning: 

A goal of the project: utilize the Quarry and adjoining valleys as mitigation habitat for the: California Red Legged Frog (CRLF) (Rana aurora draytonii), and San Francisco Garter Snake (SFGS) (Thamnophis sirtalis tetrataenia) Exhausted facility One of several significant limestone lenses boudinaged along traces of the San Andreas Fault Quarry is fed by carbonate springs Topographic position of Quarry is a bonus! Skyline Quarry role of baseflows in habitat planning

Skyline Quarryrole of baseflows in habitat planning: 

Skyline Quarry role of baseflows in habitat planning

Skyline Quarryrole of baseflows in habitat planning: 

Karstic water benefits at Skyline Quarry: Flows are characterized by low salinity and moderate pH Generally reliable baseflow sources Quarry area free from fish or mammal predators Spring flow can be gravity fed to many locales Skyline Quarry role of baseflows in habitat planning From the narrow view of habitat protection and species conservation – the quarry spring drainage is a strongly under-utilized resource

Liddell Springsrole of hydrochemistry & baseflows in habitat planning: 

A goal of the project: improve water quality and maintain discharge volume of baseflows Sources for the East Branch of Liddell Creek Important water source for the City of Santa Cruz since 1880s Historically is reported as supporting steelhead (Oncorhynchus mykiss) Recent habitat surveys found very good spawning and rearing habitat for steelhead Liddell Springs role of hydrochemistry & baseflows in habitat planning

Liddell Springrole of hydrochemistry & baseflows in habitat planning: 

Karstic water benefits in Liddell Creek: Reliable sources – near-constant inflows of 2 cfs Hydrochemistry benefits aquatic species: temperature hardness pH may also benefit steelhead by governing Cd2+ solubility Liddell Spring role of hydrochemistry & baseflows in habitat planning From the narrow view of habitat protection and species conservation – karst-emanating waters from Liddell and nearby springs enhance habitat for ‘sensitive species’

University of California at Santa Cruzrole of subsurface drainage in habitat & campus planning: 

Goal of project: reduce stormwater peaks and volumes to ‘critical’ sinkholes which drain the core campus UCSC has developed a 2,000-acre, 16,000-student campus on schist and marble bedrock The marble provided a primary source of cement for the Henry Cowell interests Campus lacks traditional stormwater drainage system University of California at Santa Cruz role of subsurface drainage in habitat & campus planning

University of California at Santa Cruzrole of subsurface drainage in habitat & campus planning: 

More Background: Rapidly evolving channel networks Sinkhole/swallowhole capacity Increased sediment production and transport to the subterranean karst system Uncertain trends in discharge of historic seeps Subterranean species and habitat subject to increased peak flows and total volume of storm flows Dolloff Cave Spider (Microcina edgewoodensis) Empire Cave Pseudoscorpion (Larca laceyi) University of California at Santa Cruz role of subsurface drainage in habitat & campus planning

University of California at Santa Cruzrole of subsurface drainage in habitat & campus planning: 

Evaluation of sinkhole capacity: Campus stormwater drainage is constrained by sinkhole infiltration rates – develop a method to evaluate sinkhole peak flow capacity University of California at Santa Cruz role of subsurface drainage in habitat & campus planning Ponded Sinkhole Illustration Inflow (I) Storage (S) Outflow (O) Overflow (OF) 4.5 – 10 cfs

University of California at Santa Cruzrole of subsurface drainage in habitat & campus planning: 

Karst system challenges at UCSC: Increase infiltration/retention at the source Increase sinkhole surface storage volume Locally re-route existing stormwater runoff Minimize sediment inflow to swallowholes and the subsurface system Clean sinkholes of ‘excess’ sediment Stabilize channels with karst-appropriate designs and technology Uncertainty of effectiveness for species preservation University of California at Santa Cruz role of subsurface drainage in habitat & campus planning Balance between species protection, habitat preservation, karst drainage functionality and ground-water quality protection

Sensitive Species and Karstic Waters Summary and Re-Cap: 

Skyline Quarry role of baseflows Liddell Spring role of hydrochemistry and baseflows UCSC role of subsurface drainage Sensitive Species and Karstic Waters Summary and Re-Cap on the surface, karstic waters support a wide range of ‘sensitive species’ and also provide opportunities for developing mitigation habitat when few other options exist – however, if we dig a little deeper, the characteristics of karst and the critters found there, demand that we practice great care in planning and developing overlying land use – thereby presenting the hydrogeologist with technical challenges which will require new and innovative investigative tools for some time to come