"ENVIRONMENTAL GIS APPLICATIONS"

Moderator - Christian Jacqz, GIS Manager, MassGIS

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Presentation by Paul Penner, GIS Specialist, Metropolitan District Commission, Division of Watershed Management

"GIS Based Land Acquisition Model"

Overview of Presentation

• Land Acquisition History, Goals, and Program Scope
• Need for Model and Process of Model Development
• Technical Overview of Model
• Use of Model

Division of Watershed Management:  Mission

Overview of the Wachusett Reservoir Watershed

Land Acquisition Goals:

• Acquire land in order of priority of importance for watershed protection
• acquire land where development may adversely affect the water supply
• acquire land to restore past land use impacts
• encourage preservation of less critical land

Program History and Future

• From 1985 to 1997, MDC has acquired 10,000 acres of land on its three active watersheds at a cost of 70 million dollars.
• At Wachusett watershed, MDC has spent more than 50 million dollars since 1990, with 32 million spent there in the past three years.
• MDC has 90 million dollars left in its land acquisition bond.

Selection Criteria in 1980’s

• Initial purchases were easily targeted at the Stillwater and Quinapoxet Corridors, where 90% of the reservoir inflow originates.  The Stillwater basin accounts for 10% of the whole system yield, contains most of the watershed’s aquifers, and was zoned commercially.

Extent of MDC Holdings on the Wachusett Reservoir Watershed in 1985

Too Complicated for Intuition Alone

• With 16,000 different ownerships in the watershed and more than 25 criteria for acquisition originally identified by staff, a model is needed to give the program direction.

Extent of MDC Holdings on the Wachusett Reservoir Watershed April 1997

Model Development

• Model has gone through four versions in 3 years.
• Current model uses 12 weighted criteria and 3 weighted zones within the watershed.
• Criteria and zone “weights” arrived at using “pairwise comparison” and the Analytical Hierarchy Process

GIS General Information

• What is GIS?
• Mapping linked to database with analytic capability
• Why Use GIS for This Model?
• Perfectly suited for complex overlay analysis
• Which Software Was Used?
• ESRI ArcInfo 7.0
• On What Platform?
• Digital Alpha unix workstation

Methodology 
Criteria Values * Multiplier = Score

• Create digital maps for each criterion
• “thematic datalayers”
• Assign the Expert Choice Value
• calculate in database
• Overlay/Combine each datalayer
• with “Union” command
• Dissolve microscopic polygons
• 200,000 to 40,000
• Calculate Score for each polygon
• use formula in database
• Determine Number and Ranges of Classes and Aggregate Polygons
• find statistical breaks in score array

Expert Choice Pairwise Criteria Rating Scale

C (MEDIUM AND HIGH YIELD AQUIFERS )EQUAL TO
G (SEWERED COMM/IND ZONING)
H (0-200’ WsPA TRIBUTARY BUFFER) MODERATELY MORE IMPORTANT
THAN I (200-400’ WsPA TRIBUTARY BUFFER)
 

RESULTS OF THE EXPERT CHOICE COMPARISON ANALYSIS

Highest Scoring Land Purchasable with Remaining Land Acquisition Funds

Summary and Evaluation

• All models are flawed
• limited number of criteria
• human factors are ignored
• “Expert” decisions may be wrong
• can’t predict the future or chaos
• However, an invaluable tool
• process stimulated discussion
• thoughtful, reasoned approach
• provides rationale for prioritizing
• focused efforts
• confirmed past purchases
• useful analysis and statistics

GIS Geographic Information System - Model Process and Output

• Hardware and Software
• Methodology
• Applications
• Output
• Summary and Evaluation

How Model is Used in Land Acquisition Program

Pros and Cons of Model

• Pros
• Incorporates staff “expert opinion” into simple priorities
• keeps focus on most sensitive land
• Avoids significant spending on low priority parcels
• spurs discussion and additional analysis
• shows interested land owners why we can’t always buy their parcel
• Cons
• can oversimplify decisions if  not used in conjunction with field walk-overs and additional analysis

Phone: (617) 727-5274 x288
E-Mail: Paul.Penner@state.ma.us
 

Presentation by Frank Biasi, GIS Manager, The Nature Conservancy

The Nature Conservancy - A Brief Description

• "Nature's real estate agent."
• Preserving habitats and species by buying the lands and waters they need to survive.
• The Nature Conservancy operates the largest private system of nature sanctuaries in     the world--more than 1,500 preserves in the United States alone.

•  Acres Protected in the U.S. since 1953:  9.5 million
•  Acres Protected outside the U.S. with TNC Assistance:  42 million
•  Acres Managed:  1.3 million (acres TNC owns or has under conservation easement)
•  Membership:  828,000
•  Corporate Associates:  1,385
•  Preserves Under Conservancy Management:  1,500
•  Natural Heritage Inventory Programs and Conservation Data Centers:   86

KEY TERMS

TNC Ecoregional Planning Units

ECOREGION-BASED CONSERVATION

• Proactive, strategic, science-based planning
• Eliminate redundancy in element representation on TNC lands
• Fill gaps in element representation on all protected lands
• Allow states to compare their occurrences to those in other states
• Maximize efficiency of conservation efforts

OVERALL GOAL

• For every ecoregion, assemble a portfolio of conservation sites that captures the ecoregion’s full biological diversity.
• The portfolio will contain multiple viable occurrences of every native species and community type, in sufficient number, distribution and quality, to insure the element’s existence and genetic variation within the ecoregion.

PORTFOLIO ASSEMBLY PROCESS

1. Identify & classify target elements
2. Set conservation goals & criteria for each element
3. Identify & map potential matrix blocks
4. Assess & classify potential matrix blocks
5. Run site selection model for matrix sites
6. Assess contribution of matrix sites to other goals
7. Repeat steps 3-6 for patch communities & species
8. Survey additional blocks to complete portfolio

CONSERVATION TARGETS

1. All viable occurrences of very rare species or communities
2. Highly viable occurrences of semi-rare species or communities
3. Large, viable landscape complexes of common communities

COMMUNITY CLASSIFICATION

•  overstory & understory plant species composition
•  heirarchical classes from gross structure to species
•  official national classification system (FWS, GS-BRD)

•  matrix - spruce-fir forest, northern hardwoods,...
•  large patch - red maple swamp, pitch pine-oak barren,...
•  small patch - calcareous fen, acidic bog,...

•  restricted - confined to ecoregion
•  limited - occurs in a few neighboring ecoregions
•  widespread - occurs across many ecoregions
•  occasional - core of distribution is in another ecoregion

CONSERVATION GOALS & CRITERIA

1. How many occurrences are needed to preserve the element?
2. What spatial distribution is necessary to represent its variation?
3. What constitutes a “viable” occurrence of the element?
4. What are the main ecological processes that affect the element?
5. What are the main threats to the element’s viability?

BASE DATALAYERS

ECOBLOCK ATTRIBUTES

• Size - total area, core & edge area, area/perimeter ratio, roundness, max. neighbor size, boundary classes
• Condition - acres & % of old growth, # & % of disturbed patches, miles of interior roads & trails, past land use
• Diversity - summary statistics on species, communities, cover types, topography, hydrology, geology, soils, etc.
• Landscape context - mgmt. status, mgmt. potential, current land uses, demographics, positive & negative proximities

ANCILLARY DATALAYERS

5.  Run site selection model for matrix sites

View Table with site selection model categories.
 

6.  Assess contribution of matrix sites to other goals

7.  Repeat steps 3-6 for patch communities & species

8.  Survey additional blocks to complete portfolio
 

ADVANTAGES OF ECOBLOCKS

•   ecologically meaningful units for research, planning, &management
•   recognizable to conservation staff, decisionmakers, and the public
•   discrete, objectively defined features
•   easily developed dataset based on public sources
•   easy to field locate and survey
•   easy to coregister with remotely sensed data
•   easy to eliminate highly developed areas from analysis
•   good method of generalizing EO locations for public display
•   correlated with parcel and census boundaries and site boundaries
•   updated regularly by outside agencies
•   heirarchical and scaleable (by road class)
•   complete landscape tesselation
•   rich area and boundary attributes (size, shape, width, traffic volumes)
•   can derive interior forest polygons, distance-to-road surfaces, etc

LIMITATIONS OF ECOBLOCKS

• don’t work as well for aquatic elements
• require periodic revisions
• huge variation in polygon size
• complex topology

Phone: (617) 542-1908 x240
Fax: (617) 482-5866
E-Mail: fbiasi@tnc.org
 

Presentation by Christian Jacqz, GIS Manager, MassGIS, Executive Office of Environmental Affairs

"GIS Data and Tools for Watershed Management"

MassGIS....

• GIS resource for state environmental agencies located in Exec. Office of Environmental Affairs
• maintains & develops statewide GIS library
• promotes standards for data and metadata
• regional scale data development
• software tools based on ESRI products
• variety of sources for existing data:
• USGS
• Federal Agencies
• EOEA agencies
• UMASS
• web site www.state.ma.us/mgis

Tools  - using centerline on PC platform

Objectives:

• create framework for  management of GIS data related to surface water such as sampling locations, gauging stations, permitted discharges etc.
• create PC based tools to support query and display of these data using dynamic segmentation model - this obviates need for end-user manipulation of GIS coverages or shape files
• extend MassGIS Data Viewer to allow for management of point and linear event models in user-friendly environment with built-in meta-data

• create single line network with hierarchical coding scheme
• implement global query algorithms
• extend theme inventory concept

Tools  - using DTM on PC platform

Objectives:

• adopt PC based tools to support interactive delineation of basins, analysis of basin characteristics and interfaces to models
• optimize raster elevation data format for accuracy and processing speed
• integrate vector and raster modes of analysis

• develop digital terrain model (expensive)
• get Spatial Analyst with hydrological extensions
• “burn in” vector network so that products are consistent
• adopt coding scheme relating sub-basins to network

Using hydro centerline network - arcs & nodes

• The centerline is an abstraction - a river system represented as a network of directed arcs
• In order to support query of this network we designed a coding scheme for a route system roughly analogous to traditional river-mile systems

• Number nodes in order of increasing distance from outlet of basin to headwaters
• The GIS “route” is sort of equivalent to a named feature, but named features start and stop along a centerline network (eg at pond inlets and outlets) and thus don’t exactly correspond to routes in this system
• Strictly speaking, a route could include any collection of arcs but we insist that they be connected
• English: Starting at the mouth of the basin number features sequentially including all reaches from confluence to furthest upstream point
• GIS: Starting with first to-node assign unassigned arcs on path from current to-node to furthest from-node into new unique routes

• Measures are computed for all confluences in terms of river miles  along the downstream route

Hydro network query tools

With this set of tools - what can you do?

• Create point and line events interactively
• Query point and linear event tables upstream, downstream
• View image link
• Highlight network upstream, downstream
• View text link

Other tools provide batch processing and data management?

• Attribute table for event theme
• Query of linked data tables
• Batch processing of coverage input
• Display of interpolated values or setup of model interface

Querying network in ArcView

• “Trace” functions operate on route attributes to create linear event tables corresponding to query results
• Upstream trace function  works with loops in the route coverage

• One script allows for display of monitoring results by coding reaches between stations
• Linear event table is created from set of point events (water quality samples) to highlight non-attainment of designated  uses - a simplistic but effective display technique

• The user selects a point and its flow path is highlighted.
• Similar abilities for the contributing area of of an area or line

Phone: (617) 727-5227 x322
Fax: (617) 227-7045
E-Mail: Christian.Jacqz@state.ma.us

Last Updated 4/19/2000
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