Current Status and Historical Trends of Seagrass in the CCBNEP Study
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FIGURES 57 Figure 1. Map of seagrass study area in Texas Coastal Bend region. 58 Figure 2. Seagrass distribution in 1988 in upper Laguna Madre. From Quammen and Onug (1993). 60 170 160 Pier 21 Mid-1950s (Galveston) drought 150 140 130 Port Isabel 120 110 100 1935 1940 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 Year Figure 3. Water level changes at Galveston Pier 21 and Port Isabel tide gauges. The drop in water levels in the mid-1950s reflects the severe drought during that period. Tide gauge data from Lyles et al. (1988) and NOAA. Nueces River at Mathis 3,000,000 2,500,000 2,000,000 1,500,000 1,000,000 500,000 0 1940 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 Calender Year Figure 4. Mean annual streamflow of the Nueces River at Mathis. Data from Texas Water Development Board and U.S. Geological Survey. 62 Mission River at Refugio 600,000 500,000 400,000 300,000 200,000 100,000 0 1940 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 Calender Year Figure 5. Mean annual streamflow of the Mission River at Refugio. Data from U.S. Geological Survey. Aransas River at Skidmore 160,000 140,000 120,000 100,000 80,000 60,000 40,000 20,000 0 1965 1970 1975 1980 1985 1990 1995 Calender Year Figure 6. Mean annual streamflow of the Aransas River at Skidmore. Data from U.S. Geological Survey. 63 Rockport Tide Levels 200 195 190 185 1.7 cm/yr 180 0.48 cm/yr 175 Mean Annual Sea Level (cm) 170 165 160 1940 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 Year Figure 8. Rates of sea level rise for two periods at the Rockport tide gauge. Tide gauge data from NOAA. 65 This page intentionally left blank. 67 Figure 10. Map showing location of USACOE dredged channels and disposal areas in Redfish/Corpus Christi Bays region. 68 890500 891000 893000892000 895000894000 897000896000 899000898000 8920 Corps of Engineers 901000900000 903000902000 905000904000 906000 907000 Dredging/Deposit Areas 908000 897000 909000 910000 911000 Redfish Bay/Harbor Island 912000 902000 913000 914000 915000 916000 DREDGED CHANNELS 917000 918000 910000 919000 920000 Channel to Aransas Pass 921000 922000 923000 924000 Corpus Christi Ship Channel 925000 926000 927000 916800 GIWW 928000 929000 930000 931000 Jetty Channel 932000 933000 934000 935000 Lydia Ann Channel 936000 937000 938000 938200 939000 OTHER 940000 940500 941000 942000 943000 Deposit Areas 944000 32442 947000 30000 Hydrology 947500 25000 948000 949000 950000 951000 20000 Channels 952000 953000 945000 954000 955000 16000 956000 957000 958000 959000 960000 11000 961000 962000 963000 7000 964000 965000 966000 2850 967000 968000 400 969000 970000 2000-1540 971000 7000 1000 972000 12000 973000 17000 4000 974000 6000 975000 22000 976000 27000 976607 32000 37000 42000 98100047000 Scale 1:100500 52000 982000 982400 0 1 2 345 983000 984000 985000 kilometers 6,262,033 GIWW at Redfish Bay 1,000,000 800,000 600,000 400,000 200,000 0 1959 1960 1961 1963 1964 1967 1970 1973 1984 Year Figure 12. Year and volume of material dredged from Redfish Bay area. From USACOE records. Lydia Ann Channel 500,000 Section 1 400,000 300,000 Section 2 200,000 Section 1 100,000 Section 3 0 1948 1954 1968 1984 Year Figure 13. Year and volume of material dredged from Lydia Ann Channel including extension to the GIWW in Aransas Bay. From USACOE records. Channel to Aransas Pass 1,200,000 1,000,000 800,000 600,000 400,000 200,000 0 1940 1957 1963 1968 1972 1979 1995 Year Figure 14. Year and volume of material dredged from channel to Aransas Pass. From USACOE records. 71 Figure 15. Wastewater discharge permit locations in Corpus Christi Bay System. From TNRCC permit records. 72 Texas Natural Resource Conservation Commission Waste Water Discharge Permit Locations Aransas Pass Portland Port Aransas N Corpus Christi Waste Water Outfall 1/4 Mile Buffer Seagrass Scale 1:300000 0 5 1015 20 25 kilometers This page intentionally left blank. 74 Figure 17. Seagrass bed distribution in 1994 for Corpus Christi Bay System. 76 Corpus Christi Bay Seagrass Study Area Scale 1:250000 0 5 10 15 20 25 kilometers HABITAT(ha) CORPUS LAGUNA NUECES RED/HAR Patchy SAV 1086.05 448.50 279.05 2156.88 Continuous SAV 1117.68 1873.93 20.77 2893.24 Algal Mat 326.90 83.96 0.00 35.23 Oyster 0.46 0.00 10.12 45.57 Wrack 2.56 0.00 0.00 151.72 Wrack & SAV 10.69 110.61 2.08 694.04 Figure 18. Seagrass bed distribution in 1994 for Aransas Bay System. 78 Aransas Bay Seagrass Study Area HABITAT(ha) ARANSAS MESQUITE ST. CHARLES Patchy SAV 634.13 122.10 102.72 Continuous SAV 601.92 113.90 244.76 Algal Mat 897.93 186.44 41.22 Macro Algae 19.30 17.38 51.84 Oyster 36.76 80.59 24.46 Wrack 9.34 0.00 0.00 Wrack & SAV 89.94 0.00 0.00 Scale 1:210000 0 5 10152025 kilometers Figure 19. Seagrass bed distribution in 1994 for Copano Bay System. 80 Copano Bay Seagrass Study Area HABITAT(ha) COPANO/MISSION PORT/SWAN Patchy SAV 182.92 188.00 Continuous SAV 289.90 439.55 Algal Mat 285.51 59.79 Macro Algae 112.62 0.00 Oyster 57.64 0.43 Wrack & SAV 0.00 96.48 Scale 1:175000 0 5 10 15 20 25 kilometers Figure 20. Seagrass species distributions in 1994 for Redfish Bay/Harbor Island complex. 82 Species Distribution for Redfish Bay/Harbor Island SEAGRASS Patchy Continuous Bare Halodule Halodule/Ruppia Halodule/Halophila Thalassia Thalassia/Halodule Thalassia/Syringodium Syringodium Ruppia Halodule/Thalassia/Ruppia Thalassia/Ruppia N Scale 1:85000 01234 5 kilometers Figure 21. Seagrass species distribution in 1994 for San Jose Island area. 84 SEAGRASS Halodule Halodule/Ruppia Halodule/Halophila Ruppia Halodule/Syringodium Thalassia Thalassia/Halodule Syringodium D N Bare A Patchy L Continuous S I E S O J A N D I S L D U N M A S Species Distribution along San Jose Island Scale 1:150000 012 34 5 N kilometers Figure 22. Seagrass species distribution in 1994 for Mustang Island area. 86 Port Aransas Species Distribution along Mustang Island AND SEAGRASS L Halodule S Halodule/Ruppia I Halodule/Halophila Ruppia G Halodule/Thalassia/Ruppia N Thalassia Thalassia/Halodule A Thalassia/Syringodium T Syringodium S N Bare U Patchy Continuous M Scale 1:80000 01 23 45 kilometers Figure 23. Seagrass distribution in 1958 for Redfish Bay/Harbor Island complex. 88 Redfish Bay/Harbor Island Complex Seagrass 1958 Seagrass(ha) Patchy 1263.91 Continuous 4120.42 Other Reefs 24.43 Spoil 293.20 Scale 1:85000 01234 5 kilometers Figure 24. Seagrass distribution in 1975 for Redfish Bay/Harbor Island complex. 90 Redfish Bay/Harbor Island Seagrass 1975 Seagrass(ha) Patchy 1453.50 Continuous 4749.63 Other Reefs 50.04 Spoil 239.25 Scale 1:85000 01234 5 kilometers Figure 25. Seagrass distribution in 1994 for Redfish Bay/Harbor Island complex. 92 Redfish Bay/Harbor Island Complex Seagrass 1994 Seagrass(ha) Patchy 2722.68 Continuous 3021.49 Other Reefs 45.57 Wrack 151.72 Scale 1:85000 01234 5 kilometers.