Effects of Urbanization and Land Cover Change on Streamflow in Maine

1. Effects of Urbanization and Land Cover Change on Streamflow in Maine

2. 2 Presentation Overview Background Population & land cover change in Maine Effects of altered stream flow Study Areas Where and why? Data Sources Methods & Analysis IHA Modifying land cover based on population Linear regressions Potential Challenges

3. 3 Has Development in Southern Maine Resulted in Altered Stream Flows? This project will seek to answer the following question: �Is there a correlation between urban development and altered stream flow characteristics in Southern Maine as compared to Northern Maine, where development has been much more limited?�

4. 4 Southern & Coastal Maine is Urbanizing, Northern Maine is Remaining Rural 1980 � 2000: Maine population increased 3.8% York County (southernmost) increased 13% Aroostook County (northernmost) decreased almost 15%

5. 5 Southern & Coastal Maine is Urbanizing, Northern Maine is Remaining Rural 1960 � 2000: Maine population increased 31.5% York County (southernmost) increased 87% Aroostook County (northernmost) decreased 30%

6. 6 Altered stream flows have ecological impacts Intra-annual variation is important to the life cycles of many aquatic, riparian and wetland species (Richter et al)

7. 7 Study Area: ~25 Catchments in Northern and Southern Maine DRAFT watersheds � Canadian/NH data? Southern and coastal counties tend to have a greater % of impervious surface (developed) Small watersheds where possible � stronger response signal to land cover (Poff et al). Limited by gage records

8. 8 All Data Publicly Available on the Internet Streamflow data USGS Daily Streamflow Data Land cover data 2001 NLCD 2004 MELCD NOAA C-CAP 1985, 1993, 1996, 2001, 2006 (some years coastal portions only) 1993 GAP *USGS Land Cover Trends Data

9. 9 Altered stream flows have ecological impacts The �Indicators of Hydrologic Alteration� (IHA) toolkit, developed by a team at The Nature Conservancy will be used to look for ecologically significant changes in hydrology over time (http://www.nature.org/initiatives/freshwater/conservationtools/art17004.html)

10. 10 IHA Will be Used to Evaluate Ecologically Significant Hydrologic Changes Over Time Hydrologic Indicators are all derived from Daily Mean Data (Available online from USGS) 32 Indicators broken into 5 categories Timing of annual extreme conditions Magnitude of monthly water condition Frequency and Duration of high and low pulses Magnitude and Duration of a annual extreme conditions Rate and frequency of water condition change

11. 11 IHA Will be Used to Evaluate Ecologically Significant Hydrologic Changes Over Time 32 Indicators broken into 5 categories Magnitude of monthly water condition Timing of annual extreme conditions Frequency and Duration of high and low pulses Magnitude and Duration of a annual extreme conditions Rate and frequency of water condition change

12. 12 IHA Will be Used to Evaluate Ecologically Significant Hydrologic Changes Over Time 32 Indicators broken into 5 categories Magnitude of monthly water condition Timing of annual extreme conditions Frequency and Duration of high and low pulses Magnitude and Duration of annual extreme conditions Rate and frequency of water condition change

13. 13 IHA Will be Used to Evaluate Ecologically Significant Hydrologic Changes Over Time 32 Indicators broken into 5 categories Magnitude of monthly water condition Timing of annual extreme conditions Frequency and Duration of high and low pulses Magnitude and Duration of a annual extreme conditions Rate and frequency of water condition change

14. 14 Population data will be used to modify land cover: a proxy for early decades Ideal: Compare land cover data to stream flow data for each decade back to ~1960�s Reality: Compare stream gage to land cover where available, use population as a proxy for other time periods

15. 15 Establish relationship between stream flow and land cover for available years

16. 16 Establish relationship between population change and land cover change

17. 17 Establish relationship between population change and land cover change

18. 18 Establish relationship between population change and land cover change

19. 19 Use population data to modify landcover in the GIS Rather than a binary developed / undeveloped classification, class as low, medium and high intensity development (1, 2, 3) Take the mean score for the watershed of interest (the maximum possible would = 3, where all cells are high intensity development Multiply developed score by the % established relative to the population change % on a cell-by-cell basis When developed cells are summarized by watershed, the % change for any given political area will be reflected in the watershed, even when the boundaries are totally different On the down side, undeveloped areas stay undeveloped.

20. 20 The modified landcover can then be used to represent years with no other land cover data

21. 21 Watershed � by - Watershed For each hydrologic characteristic examined, a map depicting study watersheds symbolized by linear regression results Tables and graphs further detailing these relationships for subject watersheds Statistical comparison of southern vs. northern watersheds Final products will include maps and graphs summarizing results

22. 22 How to account for other variables?

23. 23 How to account for other variables?

24. 24 References

25. 25 Thank you!