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The Ecological

Evolution of Place

The Ecological Evolution of Place

Ecological Evolution of Place – Presentation

Outline

I. The Issue at Hand: CONFLICT

II. An Evolving Ecology

III. A Case Study: The Seguin Comprehensive Plan

• Re-thinking our Natural Systems Assessment

• Creating an environmental Planning Framework

• A conservation mandate for land use

• Policy implications

The Issue at Hand:

CONFLICT



the CONFLICT:

Built Environment vs. Natural Environment

Who’s the bad guy here?

Our perception of this conflict between the built and the natural

changes over time, and the assigned role of protagonist and

antagonist does, as well.


Source of the Conflict #1: MAN

People are compelled to create:

• We alter places and use resources

• We are increasing in #s

We’re builders. Hence an increase in “built” fabric.

So we see an increase in # of people, who are

compelled to change their surroundings and utilize

elements of them for their own ends.


Source of Conflict #2: NATURE

• Natural systems rigidly follow natural laws

• Violation of natural laws = alteration of natural systems

• Alteration of natural systems = change in natural habitat


Some Repercussions of the Conflict:

• Alteration of factors that uphold natural

systems (air, water, climate, etc.), and of

the systems themselves

• Rearrangement of natural elements within

the built fabric

• Loss of buffers between natural and built

• Conflict along edges of built environment

• Decreasing opportunities to interface with

nature


Resolution of the Conflict

Models of conflict resolution between

built and natural systems:

• Conquest: one masters the other,

suppressing expression of its former identity

• Destruction one annihilates the other,

leaving no expression of its former identity

• Absorption one absorbs the other,

modifying expression of its former identity

• Union one joins with the other, creating a

new expression of its former identity

An Evolving Ecology



Definitions and Questions

• What is ecology?

Ecology is the study of the interrelationships between

organisms and their surroundings.

• What is evolution?

A gradual process in which something changes into

a different, and usually better/more complex form.

So the notion of an EVOLVING ECOLOGY speaks to the way that

interrelationships between organisms and their surroundings change

over time. As we alter natural systems, we alter the ecological

balance within that system.

Because of this, there are four critical questions to ask ourselves as we

shape any landscape, at any scale…


Question #1: What used to live here?

• What would this system look like if there were no human presence?

• This question directs us toward those factors we typically assess

before beginning a job, such as:

Soils

Topography

Climate

Expected native vegetation

Hydrology

Natural History



• Topo

• Floodplain

• Watershed

boundaries



• Highlands/Lowlands

• Natural Regions

• Floodplain



Expected vegetation

based on climate, soil

type, and hydrology


Question #2: What Lives Here Now?

What is the state of the built system?

What is the state of the natural system?

What is the interface of built and natural like today?

Why is that?

• Tree/vegetation surveys

• Patterns of ground and

surface water movement

• Infrastructural support

• Land use in the area

• Condition of built fabric

• Scale and impact of prior

human intervention


Question #3:

What Could Live Here?

• Based on climate, soil, and hydrology, what COULD exist here?


Question #4: What Should Live Here?

How SHOULD we use this space?

What type of environment SHOULD be created here?

Conflict resolution comes into play here, with 3 interfaces:

• Built: Built

• Built: Natural

• Natural: Natural


Natural Systems:

Ecological ContextCritical components of the natural system

Environmental AssessmentImpact of growth and development on that natural system


What lives in the area and why?


Land

• Soil

characteristics:

• Clay soils = good for

farming

• Sandy soils = allow for

water infiltration

• Bottomland soils =

shaped by

river/surface water

movement


Groundwater

• Carrizo-Wilcox aquifer

• Geologic Seam

through the area

• Water supply: city,

county, region


Surface Water

• Guadalupe River

Basin:

• From Kerr County to the

Gulf

• Seguin: Middle Guadalupe

Sub-Watershed

• Development/Use upstream

impacts conditions for

Seguin

• Seguin flanked by

Guadalupe River and

Geronimo Creek


Surface Water

•Guadalupe River in

Seguin:

•Intermittent streams are a

catchment for surface

water movement

•Floodplain covers a

significant portion of the

area


Vegetation

• Blackland prairie

• Complex grassland communities

• Root system aids in water absorption


Vegetation

• Oak woods

• Trees process CO2 (cleanse air)


Vegetation

• Riparian communities

• Vegetation stabilizes riverbanks

• Coverage creates natural corridors


How are ecological

zones determined?


Ecological

Zones


Ecological Zones

Prairie Zone

•Primarily grasses

•Grass roots aid in absorption of

surface water

•Absence of trees creates open

spaces/ viewscapes


Ecological Zones

Prairie Riparian Zone

• Mixture of trees and grasses

• Vegetation stabilizes waterways

• Collection and conveyance of

water


Ecological Zones

Oak Woods Zone

• Primarily trees

• Trees cleanse/absorb

carbon from air

• Rolling topography creates

scenic variation


Ecological Zones

Oak Woods Riparian Zone

• Primarily trees

• Trees cleanse/absorb carbon from

air

• Vegetation stabilizes waterways

• Water collection and conveyance


How do we impact the environment?


Land

• Agricultural use: approximately 75% of county land (about 350,000 acres)

• Environmental impact #1: Soil composition has been altered through agricultural pressure.

• Environmental impact #2: Surface water movement brings about soil erosion in the absence of stable vegetative communities.


Groundwater

•Groundwater is the community water

source

Environmental Impact #1:

•population growth/development =

increased groundwater use

Environmental Impact #2:

•increase of built spaces = decrease

of open spaces necessary for

recharge/ refill of subsurface water

stores


Surface Water

Water Quantity•Flooding leads to increased water volume in the system.

•Floods are magnified by urbanization.

•Increases in impervious surfaces lead to increased flow volume for the Guadalupe and its tributaries.

Water Quality•As recreation and development pressures increase

upstream, the quality of surface water in the Seguin

area will be adversely affected.

•Geronimo Creek is an area of concern for water

quality, due to nutrient and bacteria levels.


Air quality

•Current Status: Near non-attainment

(ozone)

•What’s Coming in 2008:

•Reassessment of S.A. Metropolitan Area

•Local Factors:

•Commuting lifestyle (vehicular traffic)

•Local (industrial) point sources

•Contributing Regional Factors:

•Interstate traffic/activity

•Activity in/around San Antonio


What are the primary environmental concerns as Seguin

moves into the future?

Surface Water:

•decreased infiltration due to loss of

open spaces

•increased volumes due to development

and land use upstream

Groundwater:

•increased usage due to growth and

development

•Decreased supply due to growth and

development

Air:

•Non-attainment for ozone due to

regional and local factors


Creating an Environmental Planning Framework

• If the natural system is what it is, how will that direct our design

approach in this project….concretely?

• A look back at community objectives…

• Key issue (again) = river

• Affects Drainage

• Affects Infrastructure

• Affects Access to river/creeks


Conclusion: Evolutionary Implications

• As we shape landscapes, we alter living systems. And we

determine what those systems can look like in the future.

• Our choices are:

Preservation

Restoration

Transformation

• And every project calls for a choice as to which role we could

play, and which role we should play.

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