2. Classification of Sites

Transcription

1 . Classfcaton of Stes.1 Ste Descrptons and Desgnatons Feld nvestgaton along the New Rver and Alamo Rver resulted n dentfyng and categorzng 79 potental wetland and sedmentaton basn stes. Because of the large number of stes bref descrptons are found n the appendces: New Rver stes n Appendx A and Alamo Rver stes n Appendx B. The 79 potental wetland stes were assgned an dentfer startng wth ''NR'' ndcatng a New Rver ste or "AR" ndcatng an Alamo Rver ste. Each ste was numbered accordng to ts locaton between the US-Mexco boundary and the Salton Sea wth the most northerly ste numbered 1. Thus each ste has a three- or four-dgt desgnaton. For example NR-3 s the thrty-second ste on the New Rver. Photographs and addtonal nformaton on the ste locatons are provded n the appendces. Table..1 and Table.. lst all of the stes wth approxmate acreage townshp and range locaton global postonng satellte (GPS) coordnates and ts category. Some of the stes have multple drans dschargng nto them. For these stes we lsted all the drans n the water sources column and they are assocated wth the ste lsted above them n the ste column. Categores are descrbed n Secton... Ste Categores The followng sx categores were used to classfy the sutablty of the stes for constructon of wetlands or sedmentaton basns: Category 1 Category Category 3 Sedmentaton Basn Only nfeasble and Excluded. Tables.1.1 and.1. lst the stes and ther classfcatons. Category 1 Stes. Category 1 stes may be used for ether wetlands or sedmentaton basns. These stes convey water by gravty flow from the rver or mperal rrgaton Dstrct (ld) dran nto the wetland wthout pumpng or major structural mprovements. These are preferred stes based on ther lower constructon and operatng costs. Gravty flow does not requre pumps or electrcty. Check structures or smlar devces are not requred to dvert flow to Category 1 stes. Category Stes. These stes requre constructon of structural mprovements wthn the rver or ld drans to facltate gravty flow operatons wthout pumpng. An example of a structural mprovement s a wer a small structure that acts as a small overflowng dam. Category stes are sutable for ether wetlands or sedmentaton basns. Category 3 Stes. These stes requre a pumpng system to overcome elevaton dfferences. These stes are the least desrable for constructed wetlands or sedmentaton basns based on hgher constructon and operatng costs. Sedmentaton Basn Only. These stes are not sutable for treatment wetlands but can be used to capture sedment n basns. The majorty of these stes are located where an rrgaton dran flows nto the rver. Whle the benefts of sedmentaton basns are not as great as for wetlands sedment partcles and attached pollutants wll be captured n the basns. nfeasble. Some sectons along the rvers are nfeasble for stng a wetland or sedmentaton basn because of dffcult geographcal topographc or hydraulc condtons. These condtons N:\SD81\Documents\Fnal Report\. Classfcaton.doc -1

2 nclude lmted water nflow a very narrow channel or rparan corrdor or hgh and steep channel banks. Excluded. Several sectons of the New and Alamo Rvers were excluded from the project for safety consderatons envronmental senstvty or because of other ongong projects. Wldlfe areas such as the hnperal State Wldlfe Area were excluded due to the potental for unacceptable envronmental mpacts. The rver reach close to the Calexco Arport was excluded for safety reasons because wetlands attract brds rasng the potental for conflcts between brds and arcraft. Stes NR and NR4 were excluded because of proposed projects by Caltrans and the Cty of Calexco. The Cty of Calexco's New Rver Publc Health and Envronmental Enhancement Project wll make changes to the New Rver for the frst 3.5 mles north of the US-Mexco border. The project has three phases that wll affect the Rver. The frst phase s an upgrade to the Cty of Calexco wastewater treatment plant to produce tertary-treated water. The effluent wll be used for rrgaton and to augment flows to the New Rver. The second phase wll dvert a porton of the New Rver flows through a ' x 8' covered box channel to mnmze exposure to the publc and reduce nusances. n the thrd phase rprap wll be nstalled n the exstng rver channel along wth some recreatonal amentes such as bke trals and soccer felds. Because of these actvtes potental stes along ths 3.5-mle stretch were excluded from consderaton. Table..1 Summary of New Rver Stes N:\SD81\Documents\Fnal Report\. Classfcaton.doc -

3 Table..1 Summary of New Rver Stes Contnued N:\SD81\Documents\Fnal Report\. Classfcaton.doc -3

4 Ste Category Area (acres) AR1 Excluded - AR 3 14 AR3 - Sed basn - AR4 3 1 AR5 - Sed basn - AR6 3 3 AR7 - Sed basn - AR8 3 3 AR9 - Sed basn - AR1 3 9 AR11 - Sed basn - AR AR13 64 AR AR15 Excluded - AR AR AR AR AR 1 3 AR Table.. Summary of Alamo Rver Stes Water Sources Townshp/Range 3 Dran A Dran N Dran M Dran L Dran J Dran Dran : G Dran E Dran D Dran : : Val 1 Dran Rockwood Dran Nutmeg Dran : Nettle Dran Narcssus Dran Baley Dran Standard Dran Jones Dran Margold Dran Mayflovver Dran Malva Dran Lews Dran Munyon Dran Myrtle Dran Mullen Dran Maple Dran Dartng Dran Mesqute Dran Magnola Dran Moss Dran Oak Dran Wlls Dran GPS coordnates N31 1' 5" W115 34' SO" N 33 1' W ' " N 33 1' 1" W ' 15" N 33 1' W ' N 33 9' SO" W ' 5" N 33 9' " W ' " N 33 8' 5" W ' 15" N 33 8' 3" W ' N 33 1' 55W ' 5" N 33 1' 4" W ' 1" N 33 8' W ' N 33 7' 15" W ' N 33 1' W ' N 33 6' W 115 3' N 33 4' 3" W ' N 33 ' W 115 9' N 33 ' " W 115 8' 3" N 33 1' W 115 8' 1" N 33 ' 3" W 115 8' " N 3 59' 5" W 115 8' " N 3 59' W 115 8' N:\SD81\Documents\Fnal Report\. Classfcaton.doc -4

5 Table.. Summary of Alamo Rver Stes Contnued N:\SD81\Documenls\Fnal Report\. Classfcaton.doc -5

6 .3 Rver Flows N1llllerous sources provde water to the New and Alamo rvers. Flow n the rvers vares consderably dependng on the reach and the flows from the agrcultural drans. Table.3.1 and.3 lst the flows of the CategOty 1 and stes for the New and Alamo rvers. n some cases flow data were not avalable and the cwnulatve flow s not shown. Table.3.1 Estmated Flows n Category 1 and Stes New Rver Wetland D No. Average Annual Flow (ft 3 /s) 1998 NR41 5 NR34 5 NR33 6 NR3 38 NR3 38 NR6 39 NR4 4 NR 51 NR1 57 NR19 57 NR NR NR16 59 NR15 59 NR NR9 67 NRB 67 NR1 68.!!E 1. US = Upstream DS = Downstream. Flow data provded by the mperal rrgaton Dstrct 3. Flow at NR41 s based on 1998 average flow nformaton gven by USGS Calforna Hydrologc Data Report. N:\SD81\Documents\Fnal Report\. Classfcaton.doc -6

7 ~ Table.3. Estmated Flows n Category 1 and Stes AlamoRve.- Wetland D No. Average Annual Flow (fe/s) AA37 U/S 6 AA37 DS 1 AA3 1 AA9 1 AA8 15 AA7U/S 15 AA7 DS 7 AA4 U/S 31 AA4 DS 33 AA3 U/S 44 AA3 DS 45 AAu/S 47 AA DS 6 AR1 U/S 6 AA1 DS 61 AA 6 AA19 U/S 6 AA19 DS 65 AA18 66 AA17 U/S 68 AA17 DS 68 AA16 68 AA14 75 AA13 77 AA11 U/S 77 AA11 DS 77 AA9 U/S 77 AA9 DS 79 AA7 U/S 79 AA7 DS 81 AA5U/S 81 AA5 DS 8 AA3 U/S 8 AA3 DS U/S = Upstream DS = Downstream. Flow data provded by the Colorado Rver Regonal Water Qualty Control Board 3. Flow at AA.37 s based on average 5-yr flow nformaton gven n Appendx D of the Alamo Rver TMDL (Colorado Rver RWQCB Aprl 1). The upstream flow s calculated from the percent of total flow. N:\SD81\Documents\Fnal Report\. Classfcaton.doc -7

8 A Ecologcal ssues Evaluaton Exstng bologcal and ecologcal resources are an mportant crteron for the [mal selecton of stes and as a desgn consderaton. These resources wll be evaluated durng a subsequent focused study. The Task study ste selecton process dentfed many potental stes some of whch are several hundreds of acres n sze. An accurate evaluaton of bologcal resources wll requre a focused bologcal survey of each ste. The type condton and qualty of habtat and the presence of lsted senstve threatened or endangered speces wll be determned by the survey. n general the New Rver and Alamo Rver are vewed as hghly dsturbed rparan systems whch could sgnfcantly beneft from mplementaton of the treatment wetlands and sedmentaton basns. n some areas lttle f any ndgenous habtat remans. t s unlkely that these hghly dsturbed areas would prohbt the constructon of wetlands or basns. Other areas may contan a few ecologcal resources that constran project mplementaton. Regardless future bologcal surveys and analyss may produce addtonal nformaton to reject or modfy certan stes. Analyss of nformaton provded by aeral photographs and ste vsts ndcates that a majorty of the undeveloped sectons of the rparan corrdors consst of narrow banks blanketed wth nonnatve speces. These areas are predomnated by salt cedar (Tamarx sp.) and to a lesser degree gant reed (Arundo donax). Natve speces such as bulrush (Scrpus sp.) cattal (Typha sp.) and saltbush (Atrplex sp.) are present n small areas. Although salt cedar reduces bodversty by chokng out other plant speces t provdes habtat for several brd speces n the area ncludng the federally endangered wllow flycatcher (Empdonas trll extmus) and the federally threatened Yuma clapper ral (Rallus longrostrs ssp. yumanenss). Smaller yet sgnfcant portons of the potental stes are heavly dsturbed or devoted to agrcultural uses. Areas dsturbed ether by human actvty (gradng off-road vehcles dumpng etc.) or natural occurrences (floodng eroson etc.) provde lttle to no habtat value. Agrcultural lands may provde foragng and nestng areas. Reptles and brds such as the western whptal (Cnemdophorus tgrs) and the red-taled hawk (Buteo jamacenss) feed on nsects small rodents or seed n agrcultural lands. Berms n agrcultural lands are often used by the burrowng owl (Atene cunculara ssp. hypugea) for nestng stes. Where bologcal surveys dentfy lsted speces project mplementaton actvtes that could dsturb these speces must be conducted n complance wth the Federal and/or Calforna Endangered Speces Act as well as any local resource protecton ordnances. Complance wth resource protecton regulatons wll requre acquston of permts and could requre mtgaton measures subject to approval by the U.S. Fsh and Wldlfe Servce (USFWS) the Calforna Department offsh and Game (CDFG) and/or local resource management agences. Mtgaton may nclude one or more of the followng measures: (1) constructon montorng by a certfed bologst; () alteraton of constructon perod; (3) speces relocaton; (4) stes wth valuable habtat excluded from the project; and (5) habtat creaton. Durng the pendng Task of ths project t s antcpated that certfed bologsts wll conduct ste-specfc bologcal studes to provde ste surveys vegetaton mappng and f necessary protocol surveys. Analyss of bologcal data wll be ncorporated nto the [mal ste characterzaton and selecton and nto the desgn of wetlands and basns to avod or mnmze mpacts. Table.4.1 lsts endangered threatened and senstve speces that may be present at the proposed stes. N:\SD81\Documents\Fnal Report\. Classfcaton.doc -8

9 Table.4.1 Endangered and Threatened Speces That May Occur Wthn Project Area Common :\ame Scentfc :\ame Status PLANTS Coachella Valley Mlk-vetch V1stragalus lentgnosus var. coachellae FE Person's Mlk-vetch '(1stragalus magdalenae var. person FTSE Parsh's dasy Ergeron parsh FT Algodones Dunes sunflower 'r!elanthus nveus spp. tephrodes SE BRDS Brown Pelcan "felecanus occdentals cal/omcus FESE Aleutan Canada Goose fjranta canadenss leucoparea lyuma Clapper Ral Rallus longrostrs yumanenss ST ~alforna black ral ~aterallus jamacenss cotumculus ST Southwestern Wllow Flycatcher '{mpdonax tral extmus pla woodpecker lmelanerpes uropygals!bank swallow Rpara rpara Arzona Bell's vreo Vreo bell arzonae lleast Bell's vreo Vreo bell pusllus lperegrne Falcon falco peregrnus anatum FDSE ~lfowl 'Mcrathene whtney ~aldeagle 'Halaeetus leucocephalus FSH!Desert Pupfsh Cyprnodon macularus FESE FE - Federal endangered; FT - Federal threatened; SE - State endangered; ST - State threatened FD & SD - Federal or State Delsted (Recovered) A - Agrcultural D - Desert G - Generalst RV - Rverne R - Rparan Wetland lahtat~ D R D D R R W W R R G R R G DR WA RV.5 Permttng Aquatc Pennttng Wetlands and sedmentaton basn constructon wll requre several permts. The number and type of permts necessary for constructon of the proposed project s prmarly dependent upon the proposed project's mpacts on aquatc areas under the jursdcton of the U.S. Army Corps of Engneers (ACOE) the Calforna Regonal Water Qualty Control Board (CRWQCB) and the Calforna Department offsh and Game (CDFG). The proposed project must comply wth the Federal Clean Water Act whch s regulated by the ACOE under Secton 44 and the CRWQCB under Secton 41. Currently prelmnary dscussons wth the ACOE are underway. Our prelmnary dscussons wth the ACOE ndcate that they consder the proposed N:\SD81\Documents\Fnal Report\. Classfcaton.doc -9

10 project n a favorable lght and can be expected to facltate ssuance of a pennt whch wll cover the entre project area. Determnaton of the type of permt expected date of approval and possble mtgaton measures are undetermnable at ths tme because the precse amount of mpacts to jursdctonal resources present n the project area and the amount of jursdctonal area that would be affected (e.g. fll of Waters of the U.S.) have not been determned. The nformaton needed conssts of a formal jursdctonal delneaton of the all project areas and accurate measurements of the amount of jursdctonal area that would be affected by the project. The delneaton wll determne the specfc lmts of ACOE and CDFG jursdctons n the project area. Alternatves Analyss The project purpose and need whch the alternatves would need to address s focused on the constructon of new facltes and mantenance of them for water qualty enhancement. Preparaton of a thorough alternatves analyss wll be mportant f an ndvdual 44 permt s requred. Proper consderaton of an approprate range of alternatves s partcularly mportant for the Envronmental Protecton Agency (EPA) and RWQCB and a draft descrpton of the alternatves should be sent to the EPA n the near term so that dscussons can start about the range of alternatves to be analyzed. Potental alternatves for the Secton 44 pennt analyss nclude: No Project Off-ste Alternatves Modfed Desgns Proposed Project Endangered Speces Permts Pennts for project effects on lsted speces wll be requred. Complance wth the Federal Endangered Speces Act Calforna Endangered Speces Act and any local resource protecton ordnances wll requre acquston of a pennt(s) from the approprate regulatory agences. The types and number of pennts wll be determned upon completon of focused bologcal surveys of all proposed stes. However snce the proposed project s expected to have mnmal adverse mpacts on senstve speces and wll mprove and expand wldlfe habtat t s antcpated that wldlfe agences wll vew the proposed project as favorable and provde assstance n permt ssuance. Speces protected by the U.S. Endangered Speces Act (ESA) and the Calforna Endangered Speces Act (CESA) are known as lsted speces. The ESA s admnstered by the Unted States Fsh and Wldlfe Servce (USFWS) and CESA s regulated by CDFG. The project's effects on all lsted speces must be reconcled and penntted under both of those Acts. Bologcal surveys to determne the presence of all state and federally lsted speces of plants and anmals n the project area are essental to effectve reconclaton of both Acts. The law requres federal agences to consult wth the USFWS to ensure that the actons they authorze ftmd or carry out wll not jeopardze lsted speces. n ths case the consultaton may be ntated by the Bureau of Reclamaton wth the ACOE as a cooperatng agency. n the event N:\S81\Oocuments\Fnal Report\. Classfcaton.doc -1

11 that the USFWS determnes the proposed acton wll jeopardze the speces they must ssue a ''bologcal opnon" offerng "reasonable and prudent alternatves" about how the proposed acton could be modfed to avod jeopardy to lsted speces. t s a rare excepton where projects are wthdrawn or termnated because of jeopardy to a lsted speces. The ESA secton 7 process can span up to a 35-day perod and s the most expedtous way to reconcle the ESA wth the USFWS. Reconclaton of CESA wth CDFG would follow the concluson of the secton 7 consultaton wthn 6 days va a 8.1 consstency determnaton. Whle there are several lsted speces that may be affected by the proposed project only surveys of the project stes wll determne ther presence or absence and potental to be affected. The lsted speces that could be affected by the proposed project that would be covered by the secton 7 consultaton and 8.1 consstency determnaton are shown n Table.4.1. Envronmental Complance The Bureau of Reclamaton would be the lead agency for the project's complance wth the Natonal Envronmental Polcy Act (NEPA). Envronmental documentaton s requred under NEP A n conjuncton wth the Secton 44 permt to be ssued by the ACOE and ts secton 7 consultaton wth the USFWS. The CDFG would be the lead agency for the project's complance under the Calforna Envronmental Qualty Act (CEQA) and there may be several respondng agences such as The mperal rrgaton Dstrct. An Envronmental mpact Report (ER) would also need to be prepared to satsfy CEQA requrements of the Calforna Department of Fsh and Game (CDFG) and the Regonal Water Qualty Control Board (RWQCB). We recommend the preparaton of a jont CEQAlNEPA document. The ACOE alternatves analyses wll focus on effects on jursdctonal Waters of the U.S. (under the Clean Water Act) whereas those requred by the USFWS focus on the Endangered Speces Act. A combned document would have to adequately analyze alternatves n ways that both regulatory processes are reconcled. An Envronmental mpact Statement (ES) or an Envronmental Assessment (EA) are the possble types of NEP A documentaton applcable to the project. The ACOE typcally requres an ES for mpacts to extensve areas under ther jursdcton. Those documents wll need to consder ndrect as well as drect mpacts of the project and consder bologcal resources water qualty cultural ssues and all other major envronmental ssues ncludng water qualty n the Salton Sea. Permttng Strategy Wthout a complete jursdctonal delneaton and ndvdual project ste constructon drawngs the proper permt strategy cannot be determned. However two optons are outlned below. The easest and most expedtous permt method would be to seek approval to proceed wth constructon under an exstng 44 Natonwde Permt (NWP). A NWP s a general permt that s consdered to have mnmal negatve effects on jursdctonal resources nvolves mnmal analyss has a quck turn-around (45 days for ssuance) and s not subject to publc scrutny. n ths case NWP 7 (Stream and Wetland Restoraton Actvtes) could apply and unlke most NWP's t s not lmted by acreage. Projects that have a sgnfcant negatve effect on jursdctonal resources requre an ndvdual 44 Permt (P). An P effectvely has no ssuance N:\SD81\Documents\Fnal Report\. Classfcaton.doc -11

12 tme lmtaton requres detaled analyss ncludng a 44 (b)(1) Publc nterest Revew Envronmental Assessment (Alternatves Analyss) and s formally-notced and subjected to 3 days of publc comment. The project's effects on lsted speces would be ncorporated nto ether type of 44 Permt process va a secton 7 consultaton between the ACOE and the USFWS. nformaton Needs A jursdctonal delneaton of all aquatc areas n the entre plan area wll be needed. A complete resource nventory whch ntally focuses on presence or absence of lsted speces wll also be needed. Potental downstream hydrologcal effects from the projects must also be consdered. A complete bologcal nventory wll be necessary ncludng prvate parcels. More detaled nformaton than s provded by presence/absence surveys may be necessary to support the proposed conservaton strategy. t s mportant that all bologcal surveys conform to the USFWS protocols and CDFG's gudelnes for assessng the effects of proposed projects on rare threatened and endangered plants and natural communtes. Envronmental Documentaton and Permttng Wo'c Flow The followng tasks are lsted n the order of the sequence that they would be ntated: Perform jursdctonal delneaton and prepare report. Perform bologcal surveys and prepare bologcal techncal report. Consultaton wth resource agences. Prepare constructon drawngs that show all mpacts to jursdctonal areas and crtcal resources. Modfy project plans to avod or mnmze mpacts. Prepare a lst of all permts needed. Prepare a draft Table of Contents for the combned CEQAlNEP A document for agency revew. Prepare a draft of the jont CEQAlNEP A documentaton. Crculate CEQAlNEP A document for publc revew. Revse CEQAlNEP A document and respond to comments. Approve CEQAlNEP A document. Prepare permt applcatons. Process permts. The proposed wetlands and sedmentaton basns must receve several permts to be approved for constructon. Many of these permts are standard constructon permts whle others are project specfc resource protecton complance permts. Permt condtons may cause desgn modfcatons or certan exemptons. N:\SD81\Documents\Fnal Report\. Classfcaton.doc -1

13 The proposed project must comply wth the Federal Clean Water Act whch s regulated by the U.S. Army Corps of Engneers (ACOE) under Secton 44 as well as the Calforna Regonal Water Qualty Control Board (CRWQCB) under Secton 41. Currently prelmnary dscussons wth the ACOE are underway. The ACOE may facltate ssuance of a sngle permt coverng all of the project stes. Determnaton of the type of permt expected date of approval and possble rntgaton measures are undetermnable at ths tme thus t s mportant that dscussons wth the ACOE contnue. The project s also subject to Secton 16 of the Calforna Fsh and Game Code and a 161 Streambed Alteraton Agreement would be requred. As mentoned n Secton. complance wth the Federal Endangered Speces Act Calforna Endangered Speces Act and any local resource protecton ordnances wll requre permt(s). The types and number of permts wll be determned upon completon of focused bologcal surveys. However the proposed project s expected to have mnmal mpacts on senstve speces and may mprove and expand wldlfe habtat. t s antcpated that wldlfe agences wll favorably vew the proposed project..6 Cultural Resources An ntal cultural resources study was completed for the top 35 stes along the New and Alamo Rvers n December 1 (Kyle 1). Ths study ncluded a lterature revew record search and wndsheld check. A dscusson of the results from ths study follows. The complete report s ncluded as Appendx C. Remnants from prehstorc and pre-columban cvlzatons and from poneers may be found throughout the mperal Valley. The New Rver and Alamo Rver flow wthn ancent streambeds that hstorc research ndcates may have once been heavly used by natve peoples such as the Kama for huntng washng gatherng and lvng stes as late as the rnd 18s. The New Rver corrdor was used as an ndan tral later as the Southern mmgrant Trals used by forty-nners rnltary teams and Anglos movng to Calforna n 1858 the route between the USlMexco Border and Hghway 8 became part of the Butterfeld Overland Mal Route from San Antono Texas to San Dego Calforna. Many agrcultural felds used today are founded upon and may stll use nfrastructure nstalled by early European farmers. However durng the formaton of the Salton Sea n the early 19s the New and Alamo Rvers experenced severe down cuttng; exceedng 3 feet n some places. Ths sgnfcant eroson of rverbeds and bank areas decreases the lkelhood of sgnfcant resources beng present wthn some of the proposed wetland stes. The dentfcaton recovery and protecton of cultural resources wll follow the requrements of the Calforna Envronmental Qualty Act (CEQA) as well as Federal laws procedures and polces that affect cultural resources as dscussed n Secton 5.. whch may possbly nfluence fmal ste selecton and desgn of the wetlands and basns. Although these ssues are an essental consderaton n formulatng the fmal product ste-specfc evaluaton wll occur durng a later phase of the project when focused studes are completed. Evaluaton of past records ndcates that a majorty of the proposed project stes have a good to excellent chance of contanng cultural resources. n addton The County of mperal General Plan has dentfed the Alamo and New rvers as areas wth the potental for sgnfcant cultural resources. A wndsheld survey concluded that the banks between the streambed and agrcultural felds are largely undsturbed and thus retan a good to excellent chance of contanng prehstorc artfacts. The lterature revew and record search dentfed few prevous studes or N:\SD81\Documents\Fnal Report\. Classfcaton.doc -13

14 recorded cultural resources wthn the proposed development ste areas. The lack of known cultural resources wthn the project area does not mply that any ste mayor may not contan sgnfcant cultural resources. However there s no certan ndcaton at ths pont that any proposed ste contans sgnfcant cultural resources that would result n ste excluson. n the future proposed project stes wll requre a walkover by a qualfed professonal archaeologst to examne the ste for surface evdence of archaeologcal remans pror to any earth movement and to properly evaluate and record any artfacts that may be found. n addton hstorc research wll be necessary. The sgnfcance sze and number of resources wthn each project ste wll determne future actons. Stes contanng cultural resources dentfed as sgnfcant/mportant wll requre further study excavaton and reportng as part of a data recovery program as defmed by Secton of the State CEQA Gudelnes and applcable Federal laws procedures and polces. Stes contanng cultural resources whch are dentfed as not sgnfcant wll requre no further acton..7 Evaluaton Methodology and Selecton Crtera The selecton of the 35 best-suted stes for wetlands and/or sedmentaton basns was conducted usng a numercal ratng system for both the selecton crtera and for ste sutablty. Three areas of general crtera were dentfed: constructablty socal factors and mantenance. Ten crtera fallng wthn these three areas were dentfed and are consdered mportant factors. The crtera are descrbed n the followng paragraphs. Each crteron was gven a weght between and 3 based upon ts mportance to the feasblty of the ste. A weght of 1 dentfes a crteron that s of lesser mportance whle a weght of 3 dentfes a crteron of greater mportance. Thereafter a scale was prepared for each crteron specfyng fve levels of performance that could be obtaned by a ste. Each ste was evaluated and gven a score between 1 and 5 for each crteron (one beng most favorable and 5 beng least favorable). The scores receved by each ste for a gven crteron were multpled by ts weght to obtan weghted scores. The weghted scores were summed and totals obtaned for each ste. The stes were ranked wth the lowest total scores ndcatng the most sutable stes. The weghts scales scores and rankng are shown n the mult-page Crtera Matrx at the end of Secton. Ths evaluaton was based on avalable data. The fmal scores and rankng may change to ncorporate comments provded by the Task Force resource agences and other nvolved partes. Fnal scores wll be adjusted to reflect the fmdngs of future bologcal and cultural resource studes and permttng requrements. An explanaton of these ssues s provded n Sectons. through.4. A descrpton of each crteron and the scale used to evaluate the stes are provded below. Consfrucfablty Topography Topographc features were evaluated to determne the feasblty of usng gravty flow to supply water to constructed wetlands. Successful wetlands constructon requres flow through the system wthout stagnaton. n constructed wetlands creatng the approprate landform and the use of pumpng systems may be costly. N:\SD81\Documents\Fnal Report\. Classfcaton.doc -14

15 n evaluatng the topographcal features of each ste rver bank: heghts helped dstngush Category 1 or stes from Category 3 stes. Where the rver overbanks are sgnfcantly hgher than the base flow elevaton major excavaton may be requred to transport flows from the rver to the proposed basn. Thus stes wth steep overbanks were classfed as Category 3 stes unless a drop structure was found n the ste. The followng scale was used to dentfy wetland and sedmentaton basn stes that mnmze constructon and operatons costs: 1 = -3 feet bank: heght = 4-7 feet bank: heght 3 = 8-11 feet bank: heght 4 = 1-15 feet bank: heght 5 = 16 or more feet bank: heght Ox-bows typfy flat meanderng sectons of rvers. Ox-bow meanders were dentfed as prme locatons for wetland basns. Dvertng flows from the upstream to the downstream porton of the ox-bow steepens the gradent somewhat through the wetlands ncreasng the velocty. Thus check structures and pumpng systems are less lkely to be requred. Sedmentaton-Basn-Only stes present dfferent topographc propertes and are not comparatve to wetland stes. ncomng drans are generally excellent locatons for sedment basns. The water can be detaned by expandng the area along these drans and wll result n the depost of sedment. The relatve dfference n elevaton between ncomng drans and adjacent ground elevatons was consdered to evaluate Sedment Basn Only stes. Drans must be hgh enough so gravty flow can be used but not so hgh that eroson wll result. The dfference n elevaton must also be enough so that no backflow nto the dran occurs. Accessblty Accessblty can be a major cost tem wth ste costs ncreasng sgnfcantly when access road mprovements need to be constructed. The followng scale was used for the accessblty crtera: 1 = Access by exstng freeway or major road 3 = Access by exstng unpaved road 5 = No exstng access roads to proposed ste Surroundng Land Use A key factor when evaluatng wetland stes s adjacent land use partcularly f land would have to be purchased to create the wetland. A typcal wetlands or sedmentaton basn wll requre several acres. f the avalable area s very small t may not be cost effectve to construct a basn f land acquston costs are hgh even though t may score well n other crtera. Land uses along the rver reaches nclude prme agrcultural land uncultvated land wth nvasve weeds rparan vegetaton and open space. Acquston costs vary dependng on the exstng uses. The followng scale was used for evaluatng the stes for surroundng land uses: N:\S81\Oocuments\Fnal Report\. Classfcaton.doc -15

16 = Barren land = Vegetated land 3 = Agrcultural use 4 = Prme agrculture or commercal use 5 = Surroundng clffs or housng Exstng nfrastructure Exstng drop structures located n the rvers provde sgnfcant drops n water elevaton as the rver flows downstream. The grade change allows flow through wetlands to functon by gravty wth flows movng through vegetaton wthout stagnatng. Every ste wth a drop structure and suffcent land surroundng t for constructon of wetlands or sedmentaton basn was classfed as a Category or ste. Stes wth water dscharges from agrcultural and/or muncpal drans are also good locatons for wetlands or sedmentaton basns. These stes receve a steady nflow of water allowng the wetlands vegetaton to floursh and functon correctly. The followng scale was used for evaluatng the stes for exstng nfrastructure: Socal Locaton = Exstence of drop structure and at least one dran flowng nto the ste. = Exstence of a drop structure or dran flowng nto the area 5 = Nether drop structures nor drans are found n the ste. Stes located near ctes or towns have the potental to add recreatonal value than stes farther away. Stes located downstream of ctes may treat non-pont source pollutants from legal and llct dscharges wthn the cty. Treatment wetlands located upstream of communtes can enhance downstream rver reaches through ctes and create mult-use corrdors. Park amentes bke trals and other uses may be mplemented along the rverbanks f suffcent water qualty mprovements are made. The followng scale was used for evaluatng the stes for locaton: = Ste les upstream or downstream from communty and wldlfe refuge or other stes feasble for recreatonal purposes. = Ste les upstream or downstream from communty or next to a wldlfe refuge or other stes feasble for recreatonal purposes. 3 = Ste found n vcnty of a communty and next to other stes feasble for recreatonal purposes. 4 = Ste found n vcnty of a communty or next to other stes feasble for recreatonal purposes. 5 = Ste located far from a communty and other stes feasble for recreatonal purposes. N:\SD81\Documenls\Fnal Report\. Classfcaton.doc -16

17 Publc Support Publc support s an mportant consderaton pror to constructng any ste. Stes located upstream from communtes wll mprove the rver water qualty through the communty. Stes located downstream from communtes are also favorable because dscharges from these communtes wll receve treatment. Stes that may be used as recreatonal areas wll also have better publc support. Durng feld vsts support was noted for nearby wetlands when local resdents made comments. The followng scale was used for evaluatng the stes for publc support: Multple Uses 1 = Ste les upstream or downstream from communty and wldlfe refuge or other stes feasble for recreatonal purposes. Evdence exsts of publc support for usng the ste. = Ste les upstream or downstream from communty or next to a wldlfe refuge or other stes feasble for recreatonal purposes. 3 = Ste found n vcnty of a communty and next to other stes feasble for recreatonal purposes. 4 = Ste found n vcnty of a communty or next to other stes feasble for recreatonal purposes. 5 = Ste located far from a communty and other stes feasble for recreatonal purposes. Evdence exsts of publc dslke for ste. The ratng for ths category was based on the future wetlands' ablty to support other uses prmarly recreatonal actvtes. Stes receved a better score when adjacent to exstng multple use areas such as a wldlfe refuge park or bcycle/pedestran/equestran path or trals. The followng scale was used for evaluatng the stes for multple uses: 1 = Project ste s adjacent to an exstng multple-use area and the ste desgn can easly accommodate multple recreatonal uses. = Project ste s wthn close proxmty to but not adjacent to «.5 mle) exstng multple-use areas and ste desgn can easly accommodate multple recreatonal uses. 3 = Project ste s not wthn close proxmty of an exstng multple-use area but can support other uses on a stand-alone bass because the ste sze (at least acres) and desgn that may allow for other uses. 4 = Project ste s not wthn close proxmty of an exstng multple-use area and desgn would only accommodate select uses and/or other uses may conflct wth exstng surroundng land use (5 to acres n sze). Multple use capacty of ths area would be mnmal. 5 = Project ste s not conducve to other uses because of one or more of the followng reasons: proxmty to exstng multple-use areas; ste desgn (less than 5 acres n sze); and conflctng exstng surroundng land use. Multple use of ths area s nfeasble. N:\SD81\Documents\Fnal Report\. Classfcaton.doc -17

18 Mantenance Locaton t s assumed that a mantenance center would be centrally located to provde access to both rvers. The scale shown below s based on havng a mantenance center wthn the cty of E Centro. Stes located closer to the center receved a hgher score than those located farther away. The followng scale was used for evaluatng the stes for mantenance locaton: Access 1 = Stes closest to proposed mantenance center.e. less than 8 mles from center = Stes close to proposed mantenance center.e. between 8 and 1 mles from center 3 = Stes at a medum dstance from proposed mantenance center.e. between 1 and 18 mles from center 4 = Stes far from proposed mantenance center.e. between 18 and 5 mles from center 5 = Farthest stes from proposed mantenance center.e. greater than 5 mles from center Stes must have roadway access for mantenance vehcle access. Proposed stes wth access va an arteral road or freeway receved the best ratng whle stes wthout exstng roadway access receved an unfavorable ratng. The followng scale was used for evaluatng the stes for mantenance access: 1 = Access by exstng freeway or major road 3 = Access by exstng unpaved road 5 = No exstng access roads to proposed ste Sze to Cost Rato A larger area provdes greater overall envronmental benefts and lower per acre constructon and mantenance costs than smaller stes. Therefore larger stes receved a better ratng than smaller ones. The followng scale was used for evaluatng the stes for sze to cost rato: 1 = Ste s larger or equal to acres = Ste s between 1 and acres 3 = Ste s between 5 and 1 acres 4 = Ste s between 35 and 5 acres 5 = Ste s smaller than 35 acres N:\SD81\Documents\Fnal Report\. Classfcaton.doc -18

19 .8 Summary of Ste Evaluaton Each of the stes was evaluated accordng to the crtera descrbed above and assgned a ratng. Ratngs ranged from 1 for excellent to 5 for poor. Each of the crtera was assgned a weghtng of mportance from for least mportant to 3 for very mportant The weghted ratngs assgned to each ste for each crteron were summed to produce a fnal weghted score. From the weghted scores the stes could be ranked and the top 35 stes easly dentfed. Table.8.1 and.8 provde all of the weghtng ratngs weghted scores and total scores for the New and Alamo rver stes. N:\SD81\Documents\Fnal Report\. Classfcaton.doc -19

20 Locaton Table.8.1 Evaluaton and Scores for New Rver Stes Weght ssues 1 Constructon NR NR NR3 NR4 NR5 NR6 NR7 NR8 NR9 NRO NR NR NR3 NR5 Ratng 1 Score Ratng 1 Score Ratng 1 Score Ratng 1 Score Ratng 1 Score Ratng 1 Score Ratng 1 Score Ratng 1 Score Ratng 1 Score Ratng 1 Score Ratng Score Ratng 1 Score Ratng Score Ratng 1 Score Sedment Ban Topography m m Accessblty )( 4 4 )( E" E".. Surroundng Land Use co to co Exstng nfrastructure Socal to to 4 5 m Locaton ::J < a' en Q) ::J 3 1' co ~ ::J Publc Support Multple Use Mantenance or :::: Locaton Access to Locaton Sze:Cost 3 5! 15 5! 15 5! 15 4! 1 5! 15 3! 9! 6 3! 9 5! 15 5! 15 3! 9 5! 15 Total Score ~ 51 ~ 37 ~ 5 ssues Weght NR6 NR7 NR8 NR9 NR NR1 NR NR3 NR4 NR5 NR6 NR7 NR8 NR9 Ratng Score Ratng Score Ratng Score Ratng Score Ratng Score Ratng Score Ratng Score Ratng Score Ratng Score Ratng Score Ratng 1 Score Ratng 1 Score Ratng Score Ratng 1 Score Constructon Sedment Basn Topography Accessblty Surroundng Land Use Exstng nfrastructure Socal m ~. 5' OQ to to 5 to to Locaton ' Publc Support ' : ":J. e- o Multple Use Mantenance Crtera Locaton! 4! 4! 4! 4!!! 4! 4! 4! 4! 4! 4! 4 ::E ~ Access!! ~! ;;;- ~!! 3! 6!!!!! "!!!! ~!!!!! ~ ~ ~ ~ Sze:Cost Total Score ~ 34 ~ 46 5 ~ 66 Matrx7.xlsNew Rver

21 Table.8.1 Evaluaton and Scores for New Rver Stes ssues Weght Locaton NR3 NR31 NR3 NR33 NR34 NR35 NR36 NR37 NR38 NR39 NR4 NR41 Ratng Score Ratng Score Ratng Score Ratng Score Ratng Score Ratng Score Ratng Score Ratng Score Ratng Score Ratng Score Ratng Score Ratng Score Constructon Topography Accessblty Surroundng Land Use Exstng nfrastructure Socal Locaton Publc Support Multple Use : m (") C- a. a ~ 6 ~ )( <1> en D> CD :g Mantenance Locaton Access Sze:Cost Total Score Footnotes 1. Crtera Weghtng = least mportant = mportant 3=Very mportant! ! ! 33 4! ! 4! 58! 53! 61! 54! 48! 44. Ratng Defntons 1. Excellent Mnor lmtatons. Acceptable Number of Lmtatons 3. Far Many Surmountable lmtatons 4. Dffcult Sgnfcant yet resolvable lmtatons 5. Poor Many large lmtatons requrng medum effort to resolve Crtera Matrx 7.xlsNew Rver

22 Table.8. Evaluaton and Scores for Alamo Rver Stes Weght ssues 1 Locaton AR1 AR AR3 AR4 AR5 AR6 AR7 AR8 AR9 AR1 AR11 AR1 AR13 Ratng Score Ratng Score Ratng Score Ratng Score Ratng Score Ratng Score Ratng Score Ratng Score Ratng Score Ratng Score Ratng Score Ratng Score Ratng 1 Score Constructon Sedment Basn Sedment Basn Sedment Basn Sedment Basn Sedment Basn Topography m Accessblty x " C a. Surroundng Land Use CD a Exstng nfrastructure Socal m Locaton 1 ::J < ~r Publc Support 1 ::J CD ::J Multple Use 1 ~ Mantenance Locaton 5 ~ 1 3 ~ 6 5 ~ 1 3 ~ 6 4 ~ 8 3 ~ 6 4 ~ 8 3 ~ 6 3! 6 3! 6 3! 6 3! 6 Locaton Access 3 ~ 6 3 ~ 6 3 ~ 6 3 ~ 6 3 ~ 6 3 ~ 6 ~ 4 1 ~ 1 ~ 1 ~ 1 ~ 1 ~ Sze:Cost 3 5 ~ 15 5 ~ 15 5 ~ 15 5 ~ 15 5 ~ : 9 4 : 1 Total Score ssues Weght AR14 AR15 AR16 AR17 AR18 AR19 AR AR1 AR AR3 AR4 AR5 AR6 Ratng Score Ratng Score Ratng Score Ratng Score Ratng Score Ratng Score Ratng Score Ratng J Score Ratng Score Ratng Score Ratng Score Ratng Score Ratng Score 5 Constructon Topography j 6 Accessblty 1 Surroundng Land Use 3 Exstng nfrastructure m x : " c a. 6 CD ! a.! Socal Locaton 1 m ! ::J < a Publc Support ::J CD ::J Multple Use Mantenance 5/9/6:35 Locaton 3 Access 1 Sze: Cost 3 1 Total Score AM

23 Table.8. Evaluaton and Scores for Alamo Rver Stes ssues Constructon Weght Locaton AR7 AR8 AR9 AR3 AR31 AR3 AR33 AR34 AR35 Ratng Score Ratng Score Ratng Score Ratng Score Ratng Score Ratng Score Ratng Score Ratng Score Ratng Score AR36 1 AR37 AR38 1 AR39 Ratng Score Ratng Score Ratng Score Ratng Score Topography Accessblty Surroundng Land Use Exstng nfrastructure Socal Locaton Publc Support Multple Use l Mantenance Locaton Access Sze:Cost Total Score Footnotes 1. Crtera Weghtng 1 = least mportant = mportant 3=Very mportant. Ratng Defntons 1. Excellent. Acceptable 3. Far 4. Dffcult 5. Poor Mnor lmtatons Number of Lmtatons Many Surmountable lmtatons Sgnfcant. yet resolvable lmtatons Many large lmtatons requrng medum effort to resolve 5/916:35 AM

24 .9 Summary of Top Ranked Wetlands Stes The 79 stes were evaluated numercally ranked and the top 35 stes dentfed. Stes wth the lowest scores are the top-ranked potental wetland and sedmentaton basn stes. Table.9.1 lsts the top-ranked stes wth ther approxmate acreage classfcaton as Category 1 or Category total dran and rver flows and avalable treatment capactes. The 35 top-ranked stes nclude 19 from the New Rver and 16 from the Alamo Rver. The avalable treatment capactes lsted n Table.9.1 are estmates. Actual treatment rates may vary dependng on the fmal desgn of sedmentaton basns and wetland systems. n calculatng the treatment rates we assumed a resdence tme of 7 days wthn a wetland system when treatng flows from the rvers and a 3-day resdence tme for treatng dran water n a sedmentaton basn. n some cases the avalable treatment capactes are greater than the actual dran flows. n these locatons the sedmentaton basn sze could be reduced the treatment effcency ncreased or a combnaton of both. Based on the assumed resdence tmes the 19 stes along the New Rver have the capacty to treat approxmately 1 cfs of dran flows and 75 cfs of rver flow (or approxmately 15% of the New Rver base flow). The 16 stes along the Alamo Rver have the capacty to treat 8 cfs of dran flows and 33 cfs of rver flow (or approxmately 5% of the Alamo Rver base flow). Sedmentaton Basn Only stes have dfferent propertes than stes possbly used as both wetlands and sedmentaton basns; thus scores are not comparable to Category 1 or stes. Sedmentaton Basn Only stes are not consdered n the 35 top-ranked stes. Secton.1 provdes a summary of these stes and ther rankng scores from the crtera matrx shown n Secton.8. The Task Force establshed a 35-ste lmt n order to quantfy the number of stes for whch conceptual desgn and detaled cost estmates would be prepared. The extent of the future program s not lmted to these 35 stes but wll nclude constructon of all feasble Category 1 and stes. N:\SD81 \Documents\Fnal Report\. Classfcaton.doc -4

25 Ste Rankngs Category Area Score (acres) NR NR AR NR NR AR AR AR NR NR NR AR AR AR NR AR AR AR NR AR NR NR NR NR NR AR AR NR AR NR AR NR NR NR AR Notes These stes have ncomplete or no dran flow nformaton Table Top-Ranked Wetland Stes New and Alamo Rvers Total Dran Avalable Dran Flow Treatment Rate ( cubc-ft/sec) (cu bc-ftlsec) * * * 1 * * * * Total Rver Flow (cu bc-ft/sec) Avalable Rver Treatment Rate (cubc-ftlsec) N:\SD81\Documents\Fnal Report\. Classfcaton.doc -5

26 .1 Sedmentaton Basn Only Stes Sedmentaton basns are constructed to collect and store debrs or sedment only. The capacty of the sedmentaton basns should be suffcent to retan rrgaton flows long enough to allow most of the sedment to settle out. Sedment basns must be cleaned regularly to mantan ther capacty and effectveness. The most sgnfcant sources of sedment n both rvers are agrcultural dscharges. Other sedment sources of concern are the mperal rrgaton Dstrct's dran mantenance operatons whch nclude dredgng and vegetaton removal. Mnor sources of sedment and suspended solds are n-stream eroson and wnd deposton. Table.1.1 lsts Sedmentaton Basn Only stes wth ther scores taken from Tables.8.1 and.8. ther areas and total dran flows. Table.1.1 Stes Sutable for Sedmentaton Basns Only New and Alamo Rvers Ste Score Area Total Dran Flow (acres) ( acre-ftlyr) NR NA AR NR1 53 NA AR AR AR AR Note: NA = Not Avalable The majorty of ld drans that flow nto the New or Alamo Rvers are sutable sedmentaton basn stes. Only a few stes are lsted here because most were ncluded n the wetland stes. Because of ther relatvely small sze and gravty operaton sedmentaton basns may be constructed n drans that are not part of the 35 top-ranked wetland stes thereby mprovng dran water qualty before t enters the rvers. A lst of 53 ld drans that may be used for sedmentaton basn stes along the New Rver s provded n Table.1.. Table.1.3 lsts 74 drans that flow nto the Alamo Rver wth potental stes for sedmentaton basns. Drans n both tables are lsted accordng to the secton of the rver to whch they flow nto. The numbers at the bottom of each column show the total number of drans along the partcular rver reach. Fgure.1 shows the locaton of these drans along the dfferent secton of the New and Alamo rvers. N:\SD81\Documents\Fnal Report\. Classfcaton.doc -6

27 Table.1. New Rver Potental Sedmentaton Basn Ste Drans Upper New Rver Central New Rver Lower New Rver Trfolum 11 Raymond 5 Fllaree Trfolum 1 Spruce 4 Flax Val Meserve Elder 14 Trfolum 9 Baughman Sunbeam Thompson Cole Wxom Trfolum 8 Best Fg Trfolum 7 Spruce Wormwood 7 Trfolum 6 Spruce 3 Blue Lake Trfolum 4 Lvesley Greeson O'Bren Gardner Elder No.3 Trfolum 3 Spruce 1 Elder No.1 Reed 15 Mansfeld Beech Tmothy Malan Brch 3 Reed 13 Cook A.A. No.9 Tmothy 1 Sumac A.A. No. 1 Rley 1 North Central Tamarack Sumac Gerard Rce Pnner Rce Upper Table.1.3 Alamo Rver Potental Sedmentaton Basn Ste Drans Alamo Rver Central Alamo Rver Holtvlle Man Dran Rose Dran System Central Dran systeml Lower Alamo Rver N Baley Orange Rose Central Nnth St. A Standard Oxals Redv.ood 4 South Central M Jones Olloe Graeser Barbara Worth L Margold Holtlo1l1e Man Ash K Mayflower Occdent Ash J Mahe Orent Warren Lews Oass Verde G Mulberry Oat So. Alamo No. 1 E Munyon Townshp So. Alamo Myrtle Pepper Toland Val 1 Moorhead Pomelo AA No.6 C Mullen Palm AA No. 6-A Rock'MJOd Darlng Pne Nectarne Maple Plum Nutmeg Mesqute Peach Nettle Magnola Palmetto Narcssus Moss Wlls Oak Osage Orta Bryant Wares Oleander Ohmar N:\SD81\Documents\Fnal Report\. Classfcaton.doc -7

28 Salton Sea NPt!t! 1 MOzv! Dra;n Legend Lower New Rver (LNR) Central New Rver (CNR) Upper New Rver (UNR) Salton Sea (5S) Upper Alamo Rver (UAR) Central Alamo Rver(CAR) Rose Dran System (RO) Holtvlle Man Dran (HMO) Central Dran System (CD) Lower Alamo Rver (LAR) rrr~~-----':~~ ~. ~~ f f ' " " l l - 1:1... o..n '"... ltv ~ ""*'ra! -rr --l n 11 m r ~non"'" - ~ - - ~- \ f.-.---l 11 t "L f=- ~.. ~ _ ar- ~ ~ L- ['ll--' '" -. y... J h= NTS 1"(" E DATE;.. 'YOO COOQ CA ~ 444 l SlT. :un: C 1Q.4B.UX m. 1O.4&.UX fax L l oolol!! nwe.: A~ Agrcultural Drans wth Potental Stes 9 T """... for Sedmentaton Basns FG -1.. PLOT.. _.. ' "... --=::: OESGHER~ Llt:R RRR <X..." PREPARED FOR CCTF ON THE NEW RVER DATE SUBMTTED 1 JOB NU....