Appendix C Wetlands Use Report

Transcription

1 Appendix C Wetlands Use Report Prepared by: The RETEC Group, Inc Research Blvd., Suite 106 Fort Collins, Colorado RETEC Project Number: APC Prepared for: Anadarko Petroleum Corporation P.O. Box 10 Midwest, Wyoming Prepared by: Dan Berlin, Environmental Scientist Reviewed by: Bjorn Bjorkman, Senior Risk Assessor October 25, 2004

2 Table of Contents 1 Introduction...C-1 2 Regulatory Drivers...C-1 3 Data, Methods, and Interpretation...C-2 4 Wetland Evaluation...C Reference Condition...C Produced Water Discharges...C Salt Creek and Tributaries...C-9 5 Future Wetland Conditions...C-14 6 References...C-15 List of Tables Table C-1 Salt Creek Area Wetlands List of Figures Fig C-1 Teapot Creek Field Investigation Fig C-2 Upper Salt Creek Field Investigation Fig C-3 Middle Salt Creek Field Investigation Fig C-4 Meadow Creek Field Investigation Fig C-5 Lower Salt Creek Field Investigation List of Acronyms GIS Geographic Information System NWI National Wetland Inventory PEM Palustrine emergent UAA Use Attainability Analysis USFWS United states Fish and Wildlife Service List of Attachments Attachment A Wetland Delineation Sheets Attachment B Field Survey Photos Attachment C Listing of Identified Wetlands List of Attachment B Photos Photo C-1 Photo C-2 Photo C-3 View from north end of Beaton Reservoir on berm at Teapot Creek and pocket wetland. View from pocket wetland looking south at berm on north end of Beaton Reservoir. Teapot Creek under Hwy 259, confirmed absence of wetland fringe. C-i

3 Table of Contents Photo C-4 Photo C-5 Photo C-6 Photo C-7 Photo C-8 Photo C-9 Photo C-10 Photo C-11 Photo C-12 Photo C-13 Photo C-14 Photo C-15 Photo C-16 Photo C-17 Photo C-18 Photo C-19 Photo C-20 Photo C-21 Photo C-22 Photo C-23 Photo C-24 Photo C-25 Photo C-26 Photo C-27 Teapot Creek looking upstream with very slow flow and wetland vegetation; confirmed wetland fringe. Same location as benthic station S-2. Teapot Creek looking downstream with very slow flow and wetland vegetation; confirmed wetland fringe. Castle creek at upstream monitoring station. No wetlands present. Same location as WQ-10. North Cottonwood Creek at PRCD monitoring station. No wetlands present. Dugout Creek at PRCD Monitoring station. No wetlands present. Outfall at Battery-B (flows toward Teapot Creek) Flow from LACT-B flowing toward Teapot Creek. No wetland fringe just below outfall. Flow from Battery-B flowing toward Teapot Creek. Wetland vegetation along channel. Outfall at Battery-A. Flow from Battery-A with wetland fringe just below outfall. Outfall at Meadow Creek Tensleep A. Very little water flowing. No indication of wetlands present. Outfall at Sussex B2 and C. Enhanced biocell pictured behind spillway. Wetlands along drainage. Discharge of Sussex B2- and C into Meadow Creek. Wetlands are located along Meadow Creek from water flowing downstream along Meadow Creek and backflowing up the channel. Outfall of Sussex A. No wetland fringe. Discharge of Sussex A into Meadow Creek. Meadow Creek flowing from top of picture to bottom. Wide area of wetland pictured above confluence. Sussex A discharge, with wetland fringe and Meadow Creek in background. Wetland fringe along Meadow Creek. LACT A2 West Sussex just below outfall. LACT A2 West Sussex downstream from outfall. Discharge of LACT-10 just below outfall. Wetland fringe and flowing water. Discharge of LACT-10 just below road with wetland fringe. Discharge of LACT-11A with fringe wetland along drainage. Discharge of LACT 11 (right) at the confluence with Salt Creek (top) Wetland fringe was present along the LACT-11 drainage and along Salt Creek at the confluence. Discharge of LACT-20 approximately 200 yards downstream from the outfall. Wetland fringe was present along most of the drainage. Discharge of LACT-4. Limited wetland fringe. C-ii

4 Table of Contents Photo C-28 Photo C-29 Photo C-30 Photo C-31 Photo C-32 Photo C-33 Photo C-34 Photo C-35 Photo C-36 Photo C-37 Photo C-38 Photo C-39 Photo C-40 Discharge of LACT-4 approximately 100 yards above confluence with Salt Creek. The road functions as a berm, holding water in a pond, and discharging under the road via culvert (shown here). Wetland fringe follows the drainage to Salt Creek. Discharge of LACT-5. Limited wetland fringe. Discharge of LACT-5 into Salt Creek. Wetland fringe along Salt Creek in this area as well as the lower part of the drainage from LACT-5. Upper Salt Creek looking downstream at county road bridge. Area receives backflow from an outfall of Sage Petroleum located downstream of this location. Same location as benthic station S-1. Upper Salt Creek looking upstream from county road bridge. Area receives backflow from an outfall of Sage Petroleum located downstream of this location. Same location as benthic station S-1. Salt Creek along Hwy 259 with wetland fringe and flowing water. Same location as WQ-9. Salt Creek above beaver dam. Wetland fringe. Same location as WQ- 8. Salt Creek with wetland fringe. Same location as WQ-7. Salt Creek with wetland fringe. Same location WQ-6. Salt Creek just below HWY 387. Wetland fringe extends along much of this length. Same location aswq-5 and benthic station S-7. Salt Creek with wetland fringe. Same location as WQ-4. Salt Creek with wetland fringe. Same location as WQ-3. Salt Creek with limited wetland fringe and unvegetated shore. Subject to grazing from cattle. Same location as WQ-2. Salt Creek with wetland fringe along each bank. Photo C-41 Photo C-42 Salt Creek with no wetland fringe. Same location as benthic station S- 8. Photo C-43 Salt Creek with steep banks on the left and gravel beach on the right looking downstream. Same location as benthic station S-10. Photo C-44 Salt Creek with steep banks and limited wetland vegetation. Photo C-45 Lower Salt Creek looking upstream. Limited wetland fringe on either bank. Same location as benthic station S-11. Photo C-46 Lower Salt Creek looking downstream. Limited wetland fringe. Same location as benthic station S-11. Photo C-47 Powder River looking upstream. Limited wetland fringe in pockets. Same location as benthic station P-1. Photo C-48 Powder River looking at the confluence of Salt Creek (top) with the Powder River (flowing right to left). Limited wetland fringe. Photo C-49 Powder River looking downstream. Salt Creek enters the Powder River on the right side of the photo. Limited wetland fringe. Photo C-50 Powder River looking upstream. Limited wetland fringe. Same location as benthic station P-2. C-iii

5 Table of Contents Photo C-51 Powder River looking north across the split channel. Limited wetland fringe. Same location as benthic station P-2. Photo C-52 Powder River looking downstream. Limited wetland fringe. Same location as benthic station P-2. Photo C-53 Meadow Creek looking at culvert under gravel road. No wetlands present near culvert area, transitioning to American threesquare on the right of picture. Photo C-54 Meadow Creek just downstream from culvert pictured in Photo 9. Wetland area of American threesquare along Meadow Creek. Photo C-55 Meadow Creek with slight flow and wetland fringe, looking upstream. Photo C-56 Meadow Creek with slight flow and wetland fringe, looking downstream. Photo C-57 Meadow Creek just above confluence with Salt Creek, looking downstream. Downcut, wetland fringe and standing water located along Meadow Creek. Photo C-58 Meadow Creek just above confluence with Salt Creek, looking upstream. Downcut, wetland fringe and standing water located along Meadow Creek. C-iv

6 1 Introduction This report evaluates wetlands occurring along Salt Creek and its tributaries. The presence of frequent linear wetlands is an indicator of aquatic life uses, per Wyoming Water Quality Standards. As such, this evaluation forms part of the determination of attainment of the aquatic life designated use for the Class 2C and 3B streams in the study area. Wetland occurrence along Salt Creek and its main tributaries were identified from National Wetland Inventory (NWI) maps, and then field-surveyed to characterize the amount and type of wetlands present. A quantitative assessment of field measured wetland classification and acreage was compared to the information in the NWI maps to estimate accuracy. For the field-surveyed wetlands, a qualitative evaluation of wetland functions and values was conducted to further characterize wetlands in the area. Estimates are also made of the expected wetland acreage present under a future scenario in which no produced water is discharged into Salt Creek or its tributaries. 2 Regulatory Drivers Aquatic life use is a designated use that must be met by all Class 2 and 3 waters of the state. The aquatic life (other than fish) water use is defined in Section 2(g) of Chapter 1 of the Wyoming Water Quality Rules and Regulations as water quality and habitat necessary to sustain populations of organisms other than fish. Attainment of aquatic life designated use is in the first instance based on numeric water quality standards (Wyoming Department of Environmental Quality [WDEQ], 2002). Water quality criteria based issues are more fully discussed in Appendix B (Water Quality) of this Use Attainability Analysis (UAA). In addition, chemical, physical and biological data that address aquatic life narrative water quality standards are used in a weight-of-evidence approach when determining use support. A fully supporting condition exists when biological, physical, and chemical data (along with an analysis of historical and ancillary data) indicate a functioning, sustainable condition that is not modified beyond the range of reference conditions (WDEQ, 2002). Aquatic life attainment based on a weight of evidence approach is more fully discussed in Appendix D (Aquatic Life) of this UAA. Wetlands are a component of the aquatic habitat resulting in a functioning, sustainable condition. In Class 3 water, the presence or absence of wetlands are primary indicators of identification. The absence of frequent linear wetland occurrences or impoundments within or adjacent to the stream channel over its entire length (Section 4(c)(ii) of Chapter of the WWQR) indicates that the stream is not a Class 3 water, and that the aquatic life designated use does not apply. This situation commonly pertains to Error! Reference source not found. C-1

7 Appendix C Wetlands Report ephemeral streams in this region of Wyoming. The presence or absence of wetlands therefore is an integral component of the overall evaluation of a functioning, sustainable condition. The guidance requires the definition of the reference condition. Ideally, the reference condition is another stream of similar topographical, geological and hydrological characteristics but lacking the discharge of concern. As is often observed in the arid West, however, the discharges are the source of most of the water flow. The reference condition for this area would be an intermittent or ephemeral stream, lacking most or all aquatic life. In the case of Salt Creek no reference stream containing perennial flow and similar topography and geology exists. This issue was discussed with WDEQ in the preparatory stages of this UAA, and it was agreed to consider the upstream segments of Salt Creek and its main tributaries (above any produced water points) as the closest approximation to a reference condition. For wetland evaluation the upstream area included Salt Creek just upstream of the first discharge and Teapot Creek upstream of any discharge. 3 Data, Methods, and Interpretation The general approach for evaluating wetlands was based on identification of NWI mapped linear and other wetlands prior to a field visit to verify the information in the NWI maps. Field surveys were conducted of linear and pocket wetlands in the Salt Creek area. Data were collected on presence or absence, size, and wetland type. The results of the survey were compared to wetland data from NWI surveys and are presented in this section. Surveys of reaches upstream of produced water discharges were conducted to evaluate linear wetland occurrence in order to describe the reference condition for the Salt Creek system (see Section 2). Each APC permitted discharge was visited to evaluate any pocket wetlands formed at the discharge points for the discharges. Non-APC discharges were not evaluated due to access issues. Field surveys were conducted October 7 through 13 of Wetland analyses were based on the United States Fish and Wildlife Service (USFWS) methods for NWI identification and verification (USFWS, 1995). For comparison with their mapped NWI classification, wetlands were identified according to their Cowardin class. Wetland size and shape was determined according to the federal manual for wetland delineation (Environmental Laboratory, 1987). A delineation plot was recorded in the assessment area in accordance with these methods to verify visual assessments of wetland presence or absence (See Attachment A). In all cases, the absence of wetland C-2

8 Appendix C Wetlands Report vegetation indicated the absence of a wetland, however, the absence of either wetland hydrology or wetland soils also indicated absence of a wetland. Photographs collected during the field survey are contained in Attachment B. This project defined a Data Quality Objective whereby a minimum of 10% of all NWI wetlands should be field verified. In addition, a minimum of 10% of non-wetland areas should be field verified. Differences between actual wetland shape, size, and type when compared to NWI maps were documented during field surveys. NWI wetlands were identified on maps used in the field. Any changes to NWI maps were digitized, and area was estimated with a Geographic Information System (GIS). The former and current acreage of all wetlands as estimated with the GIS are contained in Attachment C. 4 Wetland Evaluation This section provides summaries of wetland occurrences in three areas: 1. A reference condition area upstream of produced water discharges 2. Pocket wetlands present at the outflows of produced water discharges 3. Linear and other wetlands along Salt Creek and its tributaries downstream of produced water discharge. Figures C-1 through C-5 show NWI mapped wetlands and field surveyed wetlands for the Salt Creek watershed. The locations of photographs contained in Attachment B are also indicated on Figures C-1 through C-5. A summary of wetland shape and size as compiled from NWI maps and field GIS data is provided in Table C-1. Detailed information on individual NWI acreage and confirmed acreages are contained in Attachment C. 4.1 Reference Condition A reference condition defined as areas upstream of any produced water discharges, thus representing a natural flow regime, was assessed in several tributaries upstream of produced water discharges. These included Teapot Creek, Castle Creek, North Cottonwood Creek, and Dugout Creek. These streams appeared ephemeral or intermittent, and very few wetland areas are present on NWI maps or identified in the field. Teapot Creek Teapot Creek drains into upper Salt Creek and appears to be an intermittent stream with significant flow primarily during snowmelt and precipitation C-3

9 Appendix C Wetlands Report events. The creek did contain a minimal flow at the time of the field survey. The creek was surveyed from just below the berm of Beaton Reservoir down to the uppermost discharge (APC discharge Battery B, WY ), as shown on Figure C-1. Conditions along this section of Teapot Creek may be considered typical of the natural condition of creeks unaffected by produced water discharges. Photos C-1 through C-5 show conditions of wetlands observed along Teapot Creek. Original NWI wetland acreage along Teapot Creek totaled 0.89 acres. The field survey confirmed that 2.23 acres of wetlands are present along Teapot Creek. Few wetlands are listed for this area, but NWI estimates tend to underestimate the actual acreage of wetlands, as discussed below. Photos C-1 and C-2 show conditions in a wetland located just below the berm of Beaton Reservoir. A pocket wetland dominated by American threesquare (Scirpus americanus) with smaller proportions of spike rush (Eleocharis spp.) contains small pockets of standing water likely driven by the water level in the adjacent reservoir. Photo C-3 shows water present along Teapot Creek from the bridge of Hwy 259. Although soils are saturated in the channel, no wetland vegetation was present in this area. Photos C-4 and C-5 show conditions of a wetland fringe associated with the channel of Teapot Creek. Wetlands were confirmed along this stretch; however, no wetlands were shown on the NWI maps. Wetland plants at this location include American threesquare and salt grass (Distichlis stricta). As shown in Table C-1, less than 3 acres of wetlands are present along the length of Teapot Creek above the point where produced water discharges. The majority of wetlands along Teapot Creek are those shown in Photos C-4 and C-5, and constitute a linear wetland fringe. Other wetland types represented include palustrine aquatic bed, which is likely a stock reservoir not in the main channel, and a palustrine emergent wetland associated with Teapot Creek Castle Creek Castle Creek enters middle Salt Creek near Midwest, as shown on Figure C-2. Castle Creek is an intermittent or ephemeral stream with flowing water primarily during spring. It is less than 12 miles long from its headwaters to Salt Creek. The creek was dry at the time of the survey. No wetlands were identified in the NWI map along Castle Creek. No wetlands were identified during the field survey. C-4

10 Appendix C Wetlands Report Photo C-6 shows typical conditions of Castle Creek, upstream of APC discharge LACT-A. No wetland vegetation is present in this area, and the majority of the length is dry stream channel with no wetlands present. North Cottonwood Creek North Cottonwood Creek enters middle Salt Creek just upstream from Edgerton, as shown on Figure C-3. Photo C-7 shows typical conditions along this creek. North Cottonwood Creek is an intermittent or ephemeral stream with flows during snowmelt and precipitation events. No NWI wetlands were listed along this drainage, and no wetlands were identified during the field survey. Photo C-7 shows a dry streambed with no wetland vegetation, similar to the condition observed in other area creeks. Dugout Creek Summary Dugout Creek enters lower Salt Creek from the west, as shown on Figures C-3 and C-4. Photo C-8 shows typical conditions of this dry, apparently ephemeral or intermittent creek. Dugout Creek is an intermittent stream with flows during snowmelt and precipitation events. No NWI wetlands were listed for this drainage, and no wetlands were identified during the field survey. The conditions shown in Photo C-8 depict a reference condition similar to conditions in other creeks. There is a general absence of frequent linear wetlands upstream of discharges in most of the tributaries to Salt Creek. These exhibit conditions consistent with ephemeral streams. The two major branches of upper Salt Creek, Salt Creek itself and Teapot Creek appear to have more consistent flows. Upper Teapot Creek has minimal flow a good portion of the year. The frequency of wetlands is small however, amounting to less than 3 acres. Upper Salt Creek is expected to be similar (see below for more on upper Salt Creek). The natural condition in the absence of produced water flow, as evidenced by the upstream sites, results in minimal wetland formation and maintenance. 4.2 Produced Water Discharges Areas associated with discharge points are discussed in this section. Produced water discharges may create conditions conducive to wetland formation; however, flows are often too quick or warm to allow for wetland plant establishment. The APC produced water discharges are discussed below in the order that they discharge enters Salt Creek. Other dischargers are expected to be similar. C-5

11 Appendix C Wetlands Report Battery B (WY ) Photos C-9 and C-10, shown on Figure C-2, show conditions at Battery B, which discharges to a small channel flowing south to Teapot Creek. As shown in the photos, the small channel is downcut from the flowing water. Unvegetated banks (probably due to erosion), relatively fast water velocity, and hot discharge are characteristic of the area. The gradient is relatively steep at this location but becomes less steep further downstream. Photo C-11 shows a linear, fringe wetland that has developed with lower gradient further downstream from the outfall. Vegetation is dominated by American threesquare. The NWI map does not identify a wetland for this area. Battery A (WY ) Photos C-12 and C-13, shown on Figure C-2, show conditions at APC discharge Battery A, which discharges into a small channel flowing to Castle Creek. A wetland fringe is present just below the produced water outfall. This wetland is characterized as palustrine emergent, and is dominated by American threesquare. The flow from the LACT is relatively sinuous and flows only a short distance before entering Castle Creek. The NWI map does not show this wetland area. Meadow Creek Tensleep A Battery (WY ) Photo C-14, shown on Figure C-3 shows conditions at A Battery in the Meadow Creek field. There is a holding pond containing wetland vegetation on the periphery located just above the location of the photo. Below the outfall from the pond, the drainage was down-cut with unvegetated stream banks. No indication of wetland vegetation was present along the rather steep drainage; however, a large emergent wetland was present downstream from the steep drainage area in an area with much lower gradient. This wetland may be seen on Figure C-3. Sussex B2 and C (WY ) Meadow Creek field discharge Sussex B2 and C is located on Meadow Creek and (Photos C-15 and C-16, Figure C-3). An enhanced biocell is pictured in the background of Photo C-15. This system is used to volatilize sulfides present in the produced water. Wetland vegetation is present in the biocell as well as along the drainage between the outlet of the biocell and Meadow Creek. American threesquare dominated the wetland fringe along this drainage. A variety of quackgrass (Agropyron sp.) was present along with other grasses adjacent to the wetland. Photo C-16 shows flow from the biocell at the confluence with Meadow Creek. The gradient of Meadow Creek is very low at this point, and some back flow is present from this LACT discharge. The wetland is present as a fringe along the Meadow Creek channel, and is dominated by American C-6

12 Appendix C Wetlands Report threesquare. All wetlands are characterized as palustrine emergent. These wetland areas are not listed on the NWI map. Sussex A (WY ) The other produced water discharge on Meadow Creek is Sussex A. Photos C-17 through C-19 (Figure C-3) show conditions near this outfall. The outfall of LACT-Sussex A contains unvegetated muddy areas, as shown in Photo C- 17. Additional unvegetated areas associated with the drainage from this LACT to Meadow Creek are shown in Photo C-18. Flow from this LACT distributes into two small channels, each joining Meadow Creek (Photo C-18). The small eastern channel is shown in Photo C-19, with short American threesquare present along the drainage. Meadow Creek flattens a bit near the confluence with this drainage and contains a wider emergent wetland area with pockets of slowly flowing, shallow standing water. All wetlands are classified as palustrine emergent (PEM). These wetlands are not listed on the NWI map. West Sussex A2 (WY ) Discharge from this discharge point in the West Sussex field enters West Spring Draw, which flows east to Salt Creek (Figure C-4). Photos C-20 and C-21 show conditions just below the outfall at West Sussex A2. No fringe wetlands are present near this LACT, as the area is entirely unvegetated from livestock traffic and erosion from the flowing water. As shown, the drainage is deeply down-cut and subject to erosion. LACT-10 (WY ) LACT-10 discharges into Salt Creek on the west side of Hwy 259 (Figure C- 2). Photos C-22 and C-23 show produced water draining to Salt Creek via a small channel. Some wetland vegetation is interspersed within the channel from LACT-10. Some cobble and gravel can be seen in Photo C-22, indicating scour from the outfall. Photo C-23 is an area just below the road where water pools. Wetland vegetation (American threesquare) is shown along the edge of the water. The wetland is characterized as fringe PEM. The NWI map lists very small areas of palustrine intermittently flooded wetland for this location. LACT-11 (WY ) LACT-11 discharges into Salt Creek via two short channels from separate outfalls), as can be seen on Figure C-2 at the location of Photo C-24. A fringe of wetland is present along this relatively down-cut and sinuous channel. The two channels join and enter Salt Creek, as shown in Photo C-25. The NWI map shows no wetlands for this location. C-7

13 Appendix C Wetlands Report LACT-20 (WY ) LACT-20, the major produced water discharge to Salt Creek, is shown in Photo C-26 discharges to Salt Creek via a short channel (Figure C-2). Wetland vegetation is present along most of this channel, except for the areas nearest to the outfall pipe, which is very hot and flows with force sufficient to prevent vegetation from establishing. Flow becomes sufficiently calm about 10 yards downstream of the outfall for wetland vegetation to develop. The NWI map shows no wetland in this area. The fringe is characterized as palustrine emergent wetland (PEM). The NWI map shows no wetland at this location. LACT-4 (WY ) Photo C-27 shows conditions just below LACT-4 just south of Hwy 38 (Figure C-5). LACT-4 discharges to Bothwell Draw, a normally ephemeral draw flowing to Salt Creek. Although limited wetland vegetation is seen in this photo, wetland vegetation is fairly common along this draw. Photo C-28 shows the condition of the draw just below a berm created by a gravel road crossing the drainage. The culverts visible in the photo transfer the water under the road. Wetland vegetation is common along this draw, with dense stands of American threesquare and salt-cedar adjacent to the flowing water. The NWI map does not identify any wetlands in this area. The fringe is characterized as PEM. The NWI map does not show any wetland for this stretch of Bothwell Draw. LACT-5 (WY ) Summary Photo C-29 shows conditions just below LACT-5 on the short channel leading to Salt Creek (Figure C-5). This drainage is deeply down-cut, and unvegetated banks are common. However, pockets of wetland vegetation are present, with increasing density further downstream. Photo C-30 shows extensive wetland vegetation present at the confluence of the channel from LACT-5 and Salt Creek. Saltcedar is present on the left, and Russian olive (Elaeagnus angustifolia) is present on the right side of the photo. The NWI map does not show any wetland areas for this area. Small wetland fringes were observed near many but not all of the discharge points. Areas without a wetland fringe generally were eroded or with steep banks precluding development of wetland vegetation. These wetland fringes are not listed on the NWI map and are maintained exclusively by the discharged water. Their total area and linear extent is small, however, and the amount of habitat represented not large in relation to the entire Salt Creek drainage. The most developed wetland fringe was found in Bothwell Draw below LACT-4 and in the ponds associated with the Meadow Creek field discharges. C-8

14 Appendix C Wetlands Report 4.3 Salt Creek and Tributaries Salt Creek was evaluated from the uppermost location of produced water effect, shown on Figure C-2 at photo locations C-31 and C-32 to the confluence with the Powder River (Figure C-4). This assessment area extends for approximately 67 stream miles. According to the NWI map, approximately 315 acres of wetlands are present along Salt Creek. Fifty separate NWI-identified wetlands were visited as part of the field survey. Of the area visited during the field survey, approximately 79 acres of wetlands were confirmed, accounting for slightly more than 25% of the wetland acreage along Salt Creek. Much of the area of these wetlands was located in areas indicated to be non-wetland on the NWI maps. Surveyed wetland and nonwetland areas were each greater than the minimum required 10%. The results of the field survey are summarized in Table C-1. All of the wetlands along Salt Creek are dependent on the produced water dominated hydrology of the creek. Very few wetlands were noted that were not directly connected by surface water to the creek. Wetlands along Salt Creek are characterized as emergent fringe wetlands dominated by stands of American threesquare (Scirpus americanus). Salt cedar (Tamarix chinensis), salt grass (Distichlis stricta), and Russian olive (Elaeagnus angustifolia) were also observed associated with wetlands along Salt Creek. The NWI classification of these wetlands is generally riverine, but many are classified as palustrine along floodplains. Riverine wetlands identified on the NWI map along the creek edges were always present. During field verification many of the survey locations contained greater wetland acreage than indicated on the NWI maps. As shown on Table C-1, a total of 79 acres of wetland were confirmed in the field survey. The wetlands that constitute this acreage originally were estimated from the NWI map to cover 35.5 acres. Therefore, wetland acreage was 122 percent greater than indicated on the NWI map for the areas visited. In general, wetlands were frequently found to be larger than indicated on the NWI map. All of the wetlands identified along Salt Creek appeared to be dependent on the current hydrology of the creek. The majority of wetlands along Salt Creek are riverine wetlands, as shown on the NWI maps. These are generally fringe wetlands dominated by American threesquare on either bank with open water in the main channel. The most common classification along Salt Creek is riverine (R). Approximately 300 acres of wetlands along Salt Creek are riverine, and only 13 acres are listed as palustrine (P). The dominant riverine (R) wetland type is characterized as lower-perennial (2) with unconsolidated shore (US) and either temporarily flooded (A) or seasonally flooded (C), depicted as or, respectively, on the C-9

15 Appendix C Wetlands Report figures. Overall, riverine wetlands with either US or unconsolidated bottom (UB) constitute over 240 acres of wetlands along Salt Creek. Riverine classifications describe the wetland fringes along the creek, but because wetland vegetation is not present in the main channel of the creek, only the fringe is a true wetland. Therefore, the fringe receives a classification but the river channel does not. The shore or bottom is considered unconsolidated because of the erosive and depositional forces characteristic of the flowing water of the creek. Palustrine wetlands are dominated by scrub-shrub vegetation (SS) or emergent vegetation (EM), and are found to have several different hydroperiods, or flooding regimes (temporarily flooded, saturated, seasonally flooded, semipermanently flooded, and artificially flooded). Approximately 4 acres of palustrine palustrine emergent (PEM) and slightly less than 6 acres of palustrine scrub-shrub (PSS) wetlands were listed along Salt Creek. Palustrine emergent is dominated by American threesquare with smaller percentages of spike-rush and salt-grass. Palustrine scrub-shrub is dominated by salt cedar. Salt cedar, an aggressive invasive species, is likely on the increase along Salt Creek. Upper Salt Creek The upper portion of Salt Creek is characterized by intermittent flow dependent on snowmelt and precipitation. Upper Salt Creek extends from its headwaters to Coal Draw. The uppermost point surveyed as part of this survey can be seen on Figure C-2 at photo locations C-31 and C-32. Conditions at this survey location were characterized by standing water up to three feet deep in the main channel. Initially this was meant to represent an unaffected (upstream) location, but subsequent review indicated that this location is affected by backflow from the Sage Petroleum produced water discharge (WY ) a short distance downstream. The gradient in this area is low, and water discharging downstream around the bend on these photos flows in either direction from the outfall. Emergent vegetation pictured in Photos C-31 and C-32 is dominated by American threesquare. The stream banks are colonized by salt cedar. The substrate consists of clayey silt with a lighter colored oxidized layer overlying an anoxic, black layer. Due to the slow flow of this area and the prevalence of salt cedar, the NWI classification of this area is palustrine scrub-shrub (PSS). Salt Creek just east of Hwy 259 flows along a channel with a typical fringe of wetland vegetation (Photo C-33). Flows are relatively small and slow upstream from the APC discharges in this middle section. Fringe wetlands dominated by American threesquare are typical of Salt Creek from the junction with Teapot Creek to this area. Water entering Salt Creek from LACT-10 increases flow in Salt Creek, as shown in Photo C-34. A beaver dam can be seen in this photo. A small C-10

16 Appendix C Wetlands Report pocket of American threesquare is shown in the lower section of this photo. Banks in this section are generally steeper and do not create conditions conducive to wetland vegetation. Further downstream, Photo C-35 shows the location of a road that crosses Salt Creek. A thin wetland fringe is present on the bank in the foreground, but the bank is down-cut on the far side of the creek, preventing wetland vegetation from establishing. Wetland fringes are present along Salt Creek further downstream, as shown in Photo C-36. Portions of the stream bank contain unvegetated areas, but American threesquare dominates the fringe on either side of the creek. These areas are characteristic of the riverine lower-shore, unconsolidated material, temporarily flooded () category. Flow in the area near where Hwy 387 crosses Salt Creek (Photo C-37 is slow and deep with wide fringes of wetland vegetation along both sides of Salt Creek. Substrate is composed primarily of clayey silt in this area. A muskrat is seen swimming through the creek in this photo. A steep, eroding bank is also apparent in the background. Middle Salt Creek The middle portion of Salt Creek is shown on Figure C-5. Middle Salt Creek includes the length between Coal Draw and Meadow Creek. Photos C-38, C- 39, and C-40) show varying degrees of wetland development along Salt Creek. Salt Creek is wider in this area, and contains varying densities of threesquare. Much of the banks in Photo C-39 and C-40 are unvegetated due in large part to traffic from livestock accessing the creek for drinking water. These areas are examples of riverine, lower-shore, unconsolidated material, seasonally flooded wetlands (). A wide and well-developed wetland fringe is shown in Photo C-41, located approximately 100 yards above the dam near the former power station. Photo C-42 illustrates the area below the dam, with little wetland vegetation beyond saltcedar. Livestock utilize this area to access Salt Creek for drinking, limiting the amount of wetland vegetation present. A large horseshoe shaped wetland is listed on the NWI map near the location of Photo C-41 on the east side of Salt Creek (Figure C-3). This wetland is shown as palustrine, scrub-shrub, temporarily flooded (). However this was one of several wetlands identified on the NWI maps that were absent. No palustrine wetlands not directly connected to Salt Creek were found during the field investigation. In the middle section of Salt Creek, NWI descriptions of riverine wetlands were generally accurate, but palustrine wetlands were generally smaller than those specified on the NWI maps. The horseshoe shaped wetland is the remains of the old cooling ponds for the power plant. These are now filled in and covered in upland vegetation. C-11

17 Appendix C Wetlands Report Lower Salt Creek Lower Salt Creek receives drainage from Meadow Creek (discussed below) and several other ephemeral tributaries. This area of the creek is generally relatively sinuous, as shown on Figure C-4. The meanders of the creek do not closely align with the NWI mapped wetlands, likely due to changes in the meandering course of Salt Creek since the original NWI mapping. Some of the wetlands established as palustrine are in fact now along the creek edge, and should be appropriately classified as riverine. Conditions depicted in Photos C-43 and 44 show typical conditions of lower Salt Creek. Substrate generally includes varying fractions of sand, silt, and gravel. The creek is wider with larger floodplains and more gravel bars and beaches. Saltcedar and quackgrass are common along the banks, and threesquare is located in areas sheltered from high flows. Gravel bars are apparent in Photos C-45 and C-46, and wetland plants are present along the margins of the creek wherever substrate allows. This area scours more frequently, creating more difficult environments for wetland vegetation to establish. This is very characteristic of the riverine, lower shore, unconsolidated material that is temporarily flooded or seasonally flooded (wetland classes and, respectively). The mouth of Salt Creek at the Powder River is dominated by gravel substrate. Photo C-47 shows conditions on the Powder River upstream of the confluence with Salt Creek. Photo C-48 identifies the confluence with Salt Creek. Saltcedar and Russian olive are prevalent along the banks near the confluence. Photo C-49 shows cottonwoods (Populus balsamifera) along the northern banks of the Powder River. The floodplain of the Powder River across from the confluence with Salt Creek contains abundant wetland vegetation and a shallow groundwater level. These palustrine wetlands are mostly emergent (over 100 acres in the area investigated) and scrub-shrub (approx. 12 acres in the area investigated) dominated by saltcedar and cottonwoods. The Powder River upstream of Salt Creek contains large unvegetated flats with substrate composed primarily of sandy silt. Downstream of Salt Creek, the Powder River is similar to conditions noted upstream of Salt Creek. It follows long meanders with wide channels and floodplains, with substrates ranging from silty sand and gravel to unvegetated clay and silt flats (Photos C- 50, C-51 and C-52). Vegetated banks consist of saltcedar, Russian olive, meadow barley (Hordeum brachyantherum), and other grasses and forbs. Deer were observed along the floodplain of the Powder River. The amount of water flowing in Powder River was clearly larger following the confluence with Salt Creek. As shown in Photos C-50, C-51, and C-52, additional flows spread out within the channel and create additional fringe C-12

18 Appendix C Wetlands Report habitat. The small island shown in these photos is one example of additional shoreline and associated fringe wetlands created as a result of increased flows. NWI mapping of Powder River wetlands do not align with the Powder River channel due to the dynamic nature of the river channel. Because of its low gradient, it tends to meander within its main channel, but the wetlands located on its floodplain generally remain constant and appeared to be accurate when compared to NWI shapes and types. Meadow Creek Meadow Creek, a tributary receiving discharge from the Meadow Creek field, drains into lower Salt Creek from the east, as shown on Figure C-3. Meadow Creek extends for approximately 22 miles from its headwaters to the confluence with Salt Creek. Approximately 3.5 acres of wetlands are shown on the NWI map along Meadow Creek. Portions of Meadow Creek are discussed in Section 3.2 related to produced water discharge locations. Produced water enters Meadow Creek at Tensleep A Battery, but flow did not persist in Meadow Creek all the way between this outfall and the Sussex B2 and C outfall. There was water in Meadow Creek from the point the Sussex B2 and C discharge enters Meadow Creek. Photos C-53 and C-54 show conditions just above Sussex B2 and C. No flow was present at this location, but a narrow fringe of emergent wetland (Photo C-54) was present just downstream from the culvert shown in Photo C-53. This wetland area, which is apparent in the photo through the darker green American threesquare, is under hydrologic influence from the outfalls of Sussex B2 and C that are located just around the far bend shown in Photo C-54. Other upland grasses were present beyond the wetland edge. Photos C-16 and C-17, as discussed in Section 3.2, show palustrine emergent wetland resulting from the discharges. Conditions further downstream on Meadow Creek are characterized by a narrow wetland fringe along the slightly downcut channel (Photos C-55 and C-56). American threesquare dominates. The creek becomes slightly more down-cut further downstream near the confluence with Salt Creek (up to 2 ft down-cut), but contains deeper and slower flowing water and denser emergent vegetation (Photos C-57 and C-58). Salt cedar (Tamarix chinensis) is present on the edge of Meadow Creek and adjacent parts of Salt Creek near the confluence. None of the wetlands identified in the field along Meadow Creek were shown on the NWI maps. All wetlands identified along Meadow Creek were palustrine emergent wetlands (PEM) with the exception of a very small portion of the mouth of Meadow Creek, which was palustrine scrub-shrub (PSS). C-13

19 Appendix C Wetlands Report Summary Fringing riverine or palustrine emergent wetlands dominated by American threesquare occur along most of the length of Salt Creek and Meadow Creek, from the point of the uppermost produced water discharge on down. These may range from a narrow fringe to fairly broad areas, particularly in the flatter, meandering lower segments of the creek. Some downcut sections may lack these fringes. Salt cedar groves are present at various points along the creek. These result in a scrub-shrub wetland designation. Virtually all wetland areas appear directly dependent on the water flow for their maintenance. At the mouth of Salt Creek cottonwood, salt cedar and Russian olive groves are present on the Powder River floodplain. 5 Future Wetland Conditions A qualitative assessment was conducted of the wetlands noted in the field to assess likely impact of ceasing discharges to Salt Creek and its tributaries. Based on the proximity both horizontally and vertically (elevation) of the wetlands to Salt Creek, an estimate was made with regard to the percentage of each wetland expected to be lost if produced water no longer fed Salt Creek. Three categories were defined arbitrarily: 1) likely to lose <25% wetland area, 2) likely to lose 25-75% wetland area, and 3) likely to lose >75% wetland area. All wetlands associated with Salt Creek and Meadow Creek were predicted to lose >75% of their wetland area if produced water no longer fed Salt Creek. Virtually all field-evaluated wetlands were tied to the hydrology of Salt Creek and reliant on the amount of water flowing through the channel. No evidence was present that any of the wetlands resulted from groundwater discharge. The wetlands of Salt Creek are likely to be effective at recharging groundwater, a function that would be lost in the absence of flow. Any pocket wetland areas associated with the discharge points would suffer a 100% loss, as they are maintained exclusively by the discharges. Without produced water the system would revert to its natural condition. It is today not possible to definitively determine the natural flow of the system. Evidence reported in other reports for this UAA indicate that produced water provide nearly all the base flow in the system, and that Salt Creek would otherwise be intermittent. The closest to a reference conditions was considered to be current condition in major branches and tributaries upstream of any discharges (Teapot, Salt, North Cottonwood, Castle, and Dugout Creeks). These areas contain only very infrequent wetlands. Streambed conditions suggested a hydrology dominated by heavy, eroding flows. The only flow in these areas results from precipitation or snowmelt. C-14

20 Appendix C Wetlands Report Flows in the reference drainages would typically involve flash flooding and severe scouring. In the absence of wetlands maintained by constant flows, the sediment stabilizing element provided by wetland retention and filtering would be lost. As documented elsewhere, the disappearance of most or all the wetland areas would impact wildlife and aquatic organisms present in Salt Creek wetlands. The wetlands areas provide valuable habitat, otherwise uncommon in this arid area, to invertebrates, fish, and birds that are uncommon in the region. 6 References Environmental Laboratory Corps of Engineers Wetlands Delineation Manual. Technical Report Y U.S. Army Engineer Waterways Experiment Station. Vicksburg, Miss. US Fish and Wildlife Service Photo interpretation conventions for National Wetlands Inventory. NWI Group, St. Petersburg, FL. C-15

21 Tables

22 Table C-1 Wetland Acreage Identified on the NWI Maps and Confirmed During Field Surveys Cowardin Classification (in acres) Palustrine Castle Creek On NWI map of which verified in Field Teapot Creek On NWI map of which verified in Field Meadow Creek On NWI map of which verified in Field Lower Salt Creek On NWI map of which verified in Field Middle Salt Creek On NWI map of which verified in Field Upper Salt Creek On NWI map of which verified in Field PABF PABK Powder River PEMA On NWI map of which verified in Field Cowardin Classification Explanation Palustrine, Aquatic Bed, Semipermanently Flooded Palustrine, Aquatic Bed, Artificially Flooded Palustrine, Emergent, Temporarily Flooded PEMB Palustrine, Emergent, Saturated Palustrine, Emergent, Seasonally Flooded PEMF Palustrine, Emergent, Semipermanently Flooded Palustrine, Scrub-Shrub, Temporarily Flooded PUBF Palustrine, Unconsolidated Bottom, Semipermanently Flooded PUSA Palustrine, Unconsolidated Shore, Temporarily Flooded Riverine Riverine, Lower Perennial, Unconsolidated Shore, Temporarily Flooded Riverine, Lower Perennial, Unconsolidated Shore, Seasonally Flooded Riverine, Lower Perennial, R2UBF Unconsolidated Bottom, Semipermanently Riverine, Lower Perennial, Flooded R2UBH Unconsolidated Bottom, Permanently Flooded Riverine, Intermittent, Streambed, Temporarily Flooded Total OVERALL COMPARISON Total Salt Creek Acreage (NWI): acres Groundtruthed NWI acreage: 35.5 acres Total Salt Creek acreage visited: 82.5 acres True groundtruthed acreage in field: 79.1 acres P:\PROJECTS\Anadarko Salt Creek-2004\Wetlands Study\Draft to Client\[Tables_BB0819.xls]Table C-1 Page 1 of 1

23 Figures

24 Lower Castle Creek , 7 WY PUBFx PEMA PEMA Little Teapot Cr PUSAh PUSCh PEMF PE PUSAh PUSCh h PEMFh C-4, C-5 R4SBC PUSCh PEMAh WY PS 5200 WY Upper Salt Creek-Teapot Creek WY WY h 5400 TEAPOT CREEK PHOTO & LEGEND NPDES PERMITTED DISCHARGE STREAM SECTION OF INTEREST 6TH ORDER HYDROLOGIC UNIT PUSCh PEMAh 5600 WETLANDS INVESTIGATED IN FIELD PUASh PEMAh PEMA East Teapot Creek East Teapot Creek PRESENT ABSENT STREAM CLASSIFICATION Stream Order 6-7 Stream Order 4-5 Stream Order 2-3 Stream Order 1 Stream Order PEMAh PUSCh NWI WETLANDS CLASSIFICATION PALUSTRINE C-1, C-2 - PALUSTRINE, Aquatic Bed, Semipermanently Flooded, Diked/Impounded PUSA - PALUSTRINE, Unconsolidated Shore, Temporarily Flooded PUSAh - PALUSTRINE,Unconsolidated Shore, Temporarily Flooded, Diked/Impounded PUSAx - PALUSTRINE,Unconsolidated Shore, Temporarily Flooded, Excavated PUSC - PALUSTRINE,Unconsolidated Shore, Seasonally Flooded PUSCh - PALUSTRINE,Unconsolidated Shore, Seasonally Flooded, Diked/Impounded - PALUSTRINE, Scrub-Shrub, Temporarily Flooded PEMA - PALUSTRINE, Emergent, Temporarily Flooded - PALUSTRINE, Emergent, Seasonally Flooded h - PALUSTRINE, EMERGENT, Seasonally Flooded, Diked/Impounded WY RIVERINE 5800 R2UBF - RIVERINE, LOWER PERENNIAL, Unconsolidated Bottom, Semipermanently Flooded R2UBH - RIVERINE, LOWER PERENNIAL, Unconsolidated Bottom, Permanently Flooded - RIVERINE, LOWER Shore, Unconsolidated Material, Temporarily Flooded - RIVERINE, LOWER Shore, Unconsolidated Material, Seasonally Flooded - RIVERINE, INTERMITTENT, Streambed, Temporarily Flooded Miles ANADARKO SALT CREEK UAA APC TEAPOT CREEK FIELD INVESTIGATION DATE: 7/7/04 DWN. BY: KBL/ftc FILE: T:/ANADARKO_SALTCREEK/PROJECTS/WetInv_LOWERSALT.MXD FIGURE C-1

25 PUSCh C PUBFx h PABKx PABKx C PEMA 4800 PUSA C-36 hg R2UBF PUBFx C-40 C-38 C-30 C-27 C-39 PEMAh PUBFx Coal Draw Midwest C-35 C-25 C-34 C-33 Salt Creek-Coal Draw WY C-22, C-23 WY hg Edgerton PABKx C-7 PUSA WY PHOTO &- N o r t h LEGEND NPDES PERMITTED DISCHARGE STREAM SECTION OF INTEREST 6TH ORDER HYDROLOGIC UNIT WETLANDS INVESTIGATED IN FIELD PUASh PRESENT ABSENT STREAM CLASSIFICATION Stream Order 6-7 Stream Order 4-5 Stream Order 2-3 Stream Order 1 Stream Order 0 NWI WETLANDS CLASSIFICATION PALUSTRINE PUSA - PALUSTRINE, Unconsolidated Shore, Temporarily Flooded PUSAh - PALUSTRINE,Unconsolidated Shore, Temporarily Flooded, Diked/Impounded PUSAx - PALUSTRINE,Unconsolidated Shore, Temporarily Flooded, Excavated PUSC - PALUSTRINE,Unconsolidated Shore, Seasonally Flooded PUSCh - PALUSTRINE,Unconsolidated Shore, Seasonally Flooded, Diked/Impounded - PALUSTRINE, Scrub-Shrub, Temporarily Flooded PEMA - PALUSTRINE, Emergent, Temporarily Flooded - PALUSTRINE, Emergent, Seasonally Flooded h - PALUSTRINE, EMERGENT, Seasonally Flooded, Diked/Impounded C 5200 o t t on 10, 11 PUBFx PUBFx PUSA CASTLE CR WY PUSCh C-12, C-13 WY Lower Castle Creek Salt Creek-Cottonwood Creek RIVERINE R2UBF - RIVERINE, LOWER PERENNIAL, Unconsolidated Bottom, Semipermanently Flooded R2UBH - RIVERINE, LOWER PERENNIAL, Unconsolidated Bottom, Permanently Flooded - RIVERINE, LOWER Shore, Unconsolidated Material, Temporarily Flooded - RIVERINE, LOWER Shore, Unconsolidated Material, Seasonally Flooded - RIVERINE, INTERMITTENT, Streambed, Temporarily Flooded PUSAh 5200 WY C-11 C9, C10 PUBFx PEMA PEMA Little Teapot Cr PUSAh PUSCh PEMF Salt Creek- Big Bull Cedar Creek PUSAh PUSCh h PEMFh TEAPOT CREEK C-4, C-5 R4SBC PUSCh PEMAh Upper Salt Creek-Teapot Creek WY C-31, C L t39 i t WY Miles ANADARKO SALT CREEK UAA APC UPPER SALT CREEK FIELD INVESTIGATION DATE: 7/7/04 DWN. BY: KBL/ftc FILE: T:/ANADARKO_SALTCREEK/PROJECTS/WetInv_TEAPOTCR.MXD FIGURE C-2