20210825-001a: Environmental Code and Common Variances Presentation — original pdf

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Environmental Code and Common Variances E nv i ro n m e n t a l C o m m i s s i o n Re t r e a t Au g u s t 2 5 , 2 0 2 1 C I T Y O F A U S T I N W A T E R S H E D P R O T E C T I O N D E P A R T M E N T A t h a P h i l l i p s E n v i r o n m e n t a l P r o g r a m C o o r d i n a t o r W a t e r s h e d P r o t e c t i o n D e p a r t m e n t Land Development Code 25-8 Environment and the Environmental Criteria Manual C I T Y O F A U S T I N W A T E R S H E D P R O T E C T I O N D E P A R T M E N T 2 25-8 Environment S U B C H A P T E R A – WAT E R Q UA L I T Y Development Services Department: Land Use Review – Environmental Review Watershed Protection Department CEF and Floodplain Modification Review S U B C H A P T E R B – T R E E A N D N AT U R A L A R E A P ROT E C T I O N ; E N DA N G E R E D S P E C I E S Development Services Department: Community Tree Division Land Use Review – Environmental Review (notification of Endangered Species only) C I T Y O F A U S T I N W A T E R S H E D P R O T E C T I O N D E P A R T M E N T 3 25-8 Environment SUB CHAPTER A – WATE R QUAL ITY • 25- 8- 211 Water Qual i ty Control Re qui rem ent • 25- 8- 261 Cri ti cal Water Qual i ty Zone D eve l opment • 25- 8- 262 Cri ti cal Water Qual i ty Zon e Stre et Crossi ngs • 25- 8- 281 Cri ti cal Envi ronm en tal Fe ature s • 25- 8- 301 and 302 Cons tructi on on Sl ope s • 25- 8- 341 and 342 Cut and F i l l • Ar ti c l e 8- 13 L i mi ts Imper vi ous Cover • Ar ti c l e 1 3 Save Ou r Spri ngs C I T Y O F A U S T I N W A T E R S H E D P R O T E C T I O N D E P A R T M E N T 4 25-8 Environment 2 5 - 8 - 2 1 1 : C R I T I C A L WAT E R Q U A L I T Y C O N T R O L R E Q U I R M E N T Wa t e r q u a l i t y m u s t b e p r o v i d e d f o r a l l c o m m e r c i a l a n d m u l t i- f a m i l y p r o j e c t s, a n d s u b d i v i s i o n s a s a w h o l e. • Sedimentation/Filtration is most standard • Green Stormwater Infrastructure • Raingardens • Bio-filtration • Vegetated Filter strips • Retention Irrigation N o Va r i a n c e b u t s o m e p r o j e c t s c a n a p p l y f o r p a y m e n t i n l i e u . C I T Y O F A U S T I N W A T E R S H E D P R O T E C T I O N D E P A R T M E N T 5 Water Qual i ty Control s S e d i m e n t a t i o n / F i l t r a t i o n P o n d R a i n g a r d e n C I T Y O F A U S T I N W A T E R S H E D P R O T E C T I O N D E P A R T M E N T 6 25-8 Environment 2 5 - 8 - 2 6 1 : C R I T I C A L WAT E R Q U A L I T Y Z O N E D E V E L O P M E N T O n l y c e r t a i n d e v e l o p m e n t i s a l l o w e d w i t h i n a c r e e k b u f f e r • Open Space along with trails • Sustainable Urban Agriculture • Athletic fields • Utility Lines • Certain types of water quality ponds Va r i a n c e • Construction within the critical due to constrained conditions • Utility alignments • Anything else that is not listed as allowable C I T Y O F A U S T I N W A T E R S H E D P R O T E C T I O N D E P A R T M E N T 7 Creek E rosi on and Creek Heal th C I T Y O F A U S T I N W A T E R S H E D P R O T E C T I O N D E P A R T M E N T 8 Creek E rosi on and Creek Heal th Wa s t e w a t e r a n d m a n h o l e C I T Y O F A U S T I N W A T E R S H E D P R O T E C T I O N D E P A R T M E N T Wa s t e w a t e r p i p e a n d c o n c r e t e 9 25-8 Environment 2 5 - 8 - 2 6 2 : C R I T I C A L WAT E R Q U A L I T Y Z O N E S T R E E T C R O S S I N G S O n l y c e r t a i n d e v e l o p m e n t i s a l l o w e d w i t h i n a c r e e k b u f f e r • Only certain crossings are allowed • Depending on the size of the Critical Water Quality Zone • Trails are allowed to cross the creek Va r i a n c e • To have a private drive cross the Critical Water Quality Zone • To cross the CWQZ multiple times within one project C I T Y O F A U S T I N W A T E R S H E D P R O T E C T I O N D E P A R T M E N T 10 Creek C rossi ngs C u l v e r t s S p a n B r i d g e C I T Y O F A U S T I N W A T E R S H E D P R O T E C T I O N D E P A R T M E N T 11 25-8 Environment 2 5 - 8 - 2 8 1 : C R I T I C A L E N V I R O N M E N T A L F E AT U R E D e v e l o p m e n t i s n o t a l l o w e d w i t h i n t h e b u f f e r • Must protect the feature by maintaining drainage and staying out of the buffer • Buffers can be modified administratively but cannot be less than 50 feet. Va r i a n c e • Variances within 500 feet from Lake Austin are not allowed by code • Boat docks constructed within the buffer require a variance C I T Y O F A U S T I N W A T E R S H E D P R O T E C T I O N D E P A R T M E N T 12 Cri ti cal Envi ronmen tal Features B u l l C r e e k R i m r o c k T r a m I n s t a l l a t i o n o n B l u f f C I T Y O F A U S T I N W A T E R S H E D P R O T E C T I O N D E P A R T M E N T 13 25-8 Environment 2 5 - 8 - 3 4 1 a n d 2 5 - 8 - 3 4 2 : C u t a n d f i l l C u t a n d F i l l a r e l i m i t e d t o m a i n t a i n t h e n a t u r a l c h a r a c t e r o f t h e l a n d . • Limited to 4 feet. • Urban and Suburban watershed classifications can administratively vary up to 8 feet. Va r i a n c e • To exceed the allowable amount of 4 feet. • If the administrative variance does not meet the requirements:  Not less than 100 feet from a classified waterway  Not on a slope with a gradient of more than 15% C I T Y O F A U S T I N W A T E R S H E D P R O T E C T I O N D E P A R T M E N T 14 Cut an d F i l l B a r t o n C r e e k M a l l C I T Y O F A U S T I N W A T E R S H E D P R O T E C T I O N D E P A R T M E N T 15 25-8 Environment 2 5 - 8 - 3 0 1 : C o n s t r u c t i o n o f r o a d w a y o r d r i v e w a y o n s l o p e s 2 5 - 8 - 3 0 2 : C o n s t r u c t i o n o f b u i l d i n g o r p a r k i n g a r e a o n s l o p e s C o n s t r u c t i o n o n s l o p e s i s l i m i t e d t o m a i n t a i n t h e n a t u r a l c h a r a c t e r o f t h e l a n d a n d p r o t e c t t h e i n t e g r i t y o f t h e s l o p e. • 25-8-301: Roads or drives cannot cross slopes greater than 15% unless it is necessary to provide primary access to 2 contiguous acres with less than 15% slope or a building site with at least 5 units. • 25-8-302: No building or parking structure on slope greater than 25% and no parking lot on slope greater than 15%. Va r i a n c e • Secondary access crossing slopes greater that 15% • Not meeting requirements for crossing slopes • Building on slopes greater than 25% C I T Y O F A U S T I N W A T E R S H E D P R O T E C T I O N D E P A R T M E N T 16 Constructi on of Sl opes E r o s i o n R e t a i n i n g w a l l C I T Y O F A U S T I N W A T E R S H E D P R O T E C T I O N D E P A R T M E N T 17 25-8 Environment A r t i c l e 8 t h r u A r t i c l e 1 3 : I m p e r v i o u s C o v e r L i m i t i n g i m p e r v i o u s c o v e r a l l o w s w a t e r t o i n f i l t r a t e o n s i t e w h i c h r e c h a r g e s g r o u n d w a t e r a n d h e l p s t o c o n t r o l r u n - o f f a n d f l o o d i n g . • Allowable impervious cover varies due to watershed classification and use • Desired Development Zone uses gross site area to calculate impervious cover • Drinking Water Protection Zone use net site area to calculate impervious cover • Net site area = Gross area minus CWQZ, WQTZ, WW fields, and % of certain slopes • Barton Springs Zone is the most restrictive Va r i a n c e • To increase the allowable impervious cover • Impervious cover increase within the BSZ requires an SOS amendment C I T Y O F A U S T I N W A T E R S H E D P R O T E C T I O N D E P A R T M E N T 18 25-8 Environment A r t i c l e 1 3 : S a v e O u r S p r i n g s L i m i t s i m p e r v i o u s c o v e r a n d r e q u i r e s a d d i t i o n a l w a t e r q u a l i t y. • Includes all area within the Barton Springs Zone watershed classification • Edwards Aquifer Recharge Zone - 15% NSA impervious cover • Barton Creek watershed- 20% NSA impervious cover • Edwards Aquifer Contributing Zone - 25% NSA impervious cover • Requires SOS non-degradation water quality N o v a r i a n c e s a l l o w e d t o i m p e r v i o u s c o v e r o r w a t e r q u a l i t y r e q u i r e m e n t s . M o d i f i c a t i o n w i l l r e q u i r e a s i t e - s p e c i f i c a m e n d m e n t t o S O S. C I T Y O F A U S T I N W A T E R S H E D P R O T E C T I O N D E P A R T M E N T 19 Questions? L i z J o h n s t o n , D e p u t y E n v i r o n m e n t a l O f f i c e r L i z . J o h n s t o n @ a u s t i n t e x a s . g o v A t h a P h i l l i p s, E n v i r o n m e n t a l P r o g r a m C o o r d i n a t o r A t h a . P h i l l i p s @ a u s t i n t e x a s . g o v C I T Y O F A U S T I N W A T E R S H E D P R O T E C T I O N D E P A R T M E N T 20