diff --git a/NAMESPACE b/NAMESPACE
index f725248..2449c42 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -14,6 +14,14 @@ export(flow_threshold_remove_baseflow)
 export(flow_threshold_remove_baseflow_apply)
 export(flow_threshold_split)
 export(flow_threshold_split_apply)
+export(habitat_drc)
+export(habitat_drc_weighted)
+export(habitat_fsa)
+export(habitat_fsa_duration)
+export(habitat_fsa_duration_reach)
+export(habitat_fsa_reach)
+export(habitat_fsa_reach_scaled)
+export(habitat_predict)
 export(hex_color_blend)
 export(linterp)
 export(oom_range)
diff --git a/R/habitat.R b/R/habitat.R
new file mode 100644
index 0000000..b17a929
--- /dev/null
+++ b/R/habitat.R
@@ -0,0 +1,542 @@
+#' Create Flow-To-Suitable-Area-Curve for Individual Reach (unscaled)
+#'
+#' @param reach Integer `comid` identifier for reach
+#' @param habitat_type Either "rearing" or "spawning"
+#' @param units Desired units for output, either "ft" for square ft per linear ft, or "ac" for total acres
+#'
+#' @returns A `tibble` with columns for flow (`flow_cfs`) and suitable habitat (`habitat`)
+#' @md
+#' @export
+#'
+#' @examples
+#'
+#' habitat_fsa_reach(reach = 7978069)
+#'
+habitat_fsa_reach <- function(reach, habitat_type = "rearing", units = "ft") {
+
+  mode_unit <-
+    if (units %in% c("ft", "feet", "ft2/lf")) "ft" else
+      if(units %in% c("ac", "acres")) "ac"
+
+  fsa <-
+    switch(mode_unit,
+           "ft" =
+             habistat::wua_predicted |>
+             filter(habitat == habitat_type) |>
+             filter(comid == reach) |>
+             select(flow_cfs,
+                    habitat = wua_per_lf_pred),
+           "ac" =
+             habistat::wua_predicted |>
+             filter(habitat == habitat_type) |>
+             filter(comid == reach) |>
+             transmute(flow_cfs,
+                       habitat = wua_per_lf_pred * reach_length_ft / 43560))
+
+  return(fsa)
+
+}
+
+#' Create Flow-To-Suitable-Area Curve for Individual Reach (scaled by multiplier)
+#'
+#' @param reach Integer `comid` identifier for reach
+#' @param multiplier Numeric multiplier to scale flow
+#' @param habitat_type Either "rearing" (default) or "spawning"
+#' @param units Desired units for output, either "ft" for square ft per linear ft, or "ac" for total acres
+#'
+#' @returns A `tibble` with columns for flow (`flow_cfs`) and suitable habitat (`habitat`)
+#' @md
+#' @export
+#'
+#' @examples
+#'
+#' habitat_fsa_reach_scaled(reach = 7978069)
+#'
+habitat_fsa_reach_scaled <- function(reach, multiplier, habitat_type = "rearing", units = "ft") {
+
+  fsa <-
+    habistat::habitat_fsa_reach(reach,
+                                habitat_type = habitat_type,
+                                units = units)
+
+  return(tibble(flow_cfs = fsa$flow_cfs,
+                habitat = approx(x = fsa$flow_cfs * multiplier,
+                                 y = fsa$habitat,
+                                 xout = fsa$flow_cfs,
+                                 rule = 2:2,
+                                 method = "linear",
+                                 na.rm = F)$y))
+
+}
+
+#' Create Flow-To-Suitable-Area Curve for Reach, Mainstem, or Watershed
+#'
+#' @param reach Integer `comid` identifier for reach (must provide either reach, mainstem, OR watershed)
+#' @param mainstem String name for mainstem (refer to `cv_mainstems` dataset for options)
+#' @param watershed String name for watershed (refer to `cv_watersheds` dataset for options)
+#' @param habitat_type Either "rearing" (default) or "spawning"
+#' @param units Either "ft" for square ft per linear ft, or "ac" for total acres
+#'
+#' @returns A `tibble` with columns for flow (`flow_cfs`) and suitable habitat (`habitat`)
+#' @md
+#' @export
+#'
+#' @examples
+#'
+#' habitat_fsa(reach = 7978069, units = "ft")
+#'
+#' habitat_fsa(mainstem = "Feather River", units = "ac")
+#'
+habitat_fsa <- function(reach, mainstem, watershed,
+                        habitat_type = "rearing", units = "ft") {
+
+  mode_geom <-
+    if (!missing(reach)) "reach" else
+      if (!missing(mainstem)) "mainstem" else
+        if (!missing(watershed)) "watershed"
+
+  mode_unit <-
+    if (units %in% c("ft", "feet", "ft2/lf")) "ft" else
+      if(units %in% c("ac", "acres")) "ac"
+
+  if (mode_geom == "reach") {
+
+    habitat_fsa_reach(reach = reach,
+                      habitat_type = habitat_type,
+                      units = units)
+
+  } else if (mode_geom %in% c("mainstem", "watershed")) {
+
+    group_var <-
+      switch(mode_geom,
+             "mainstem" = "river_cvpia",
+             "watershed" = "watershed_level_3")
+
+    flow_xw <-
+      switch(mode_geom,
+             "mainstem" = habistat::cv_mainstems_flow_xw,
+             "watershed" = habistat::cv_watersheds_flow_xw)
+
+    comids <-
+      switch(mode_geom,
+             "mainstem" =
+               habistat::cv_mainstems |>
+               filter(river_cvpia == mainstem) |>
+               pull(comid),
+             "watershed" =
+               habistat::cv_watersheds |>
+               filter(river_cvpia == mainstem) |>
+               pull(comid))
+
+    scaled_predictions <-
+      flow_xw |>
+      filter(comid %in% comids) |>
+      mutate(fsa = map2(comid, multiplier, function(x, y) {
+        habistat::habitat_fsa_reach_scaled(reach = x,
+                                           multiplier = y,
+                                           habitat_type = habitat_type,
+                                           units = "ft")})) |> # output in units ft2/ft
+      inner_join(habistat::flowline_attr |> select(comid, reach_length_ft),
+                 by = join_by(comid)) |>
+      unnest(fsa) |>
+      mutate(habitat_ft2 = habitat * reach_length_ft)
+
+    switch(mode_unit,
+           "ft" =
+             scaled_predictions |>
+             group_by(flow_cfs) |>
+             summarize(habitat = sum(habitat_ft2, na.rm = T) / sum(reach_length_ft),
+                       .groups = "drop"),
+           "ac" =
+             scaled_predictions |>
+             group_by(flow_cfs) |>
+             summarize(habitat = sum(habitat_ft2, na.rm = T) / 43560,
+                       .groups = "drop"))
+
+  }
+
+}
+
+#' Create Duration Suitability Rating Curve for a streamgage
+#'
+#' @param streamgage Three-letter CDEC identifier for the streamgage
+#' @param habitat_type Either "rearing" (default) or "spawning"
+#' @param run One of "fall" (default), "late fall", "winter", "spring", or "steelhead"
+#' @param wy_group Either "Dry" or "Wet" for water year type scenario
+#' @param gradient For rearing, either "Valley Foothill" (default) or "Valley Lowland"
+#'
+#' @returns A `tibble` with columns for flow (`flow_cfs`) and duration habitat suitability index (`durhsi`)
+#' @md
+#' @export
+#'
+#' @examples
+#'
+#' habitat_drc("FSB", habitat_type="rearing", gradient = "Valley Foothill")
+#'
+habitat_drc <- function(streamgage,
+                        habitat_type = "rearing",
+                        run = "fall",
+                        wy_group = "Dry",
+                        gradient = "Valley Foothill") {
+
+  drc_filtered <-
+    habistat::streamgage_duration_rating_curves |>
+    filter((station_id == str_to_lower(streamgage)) &
+             (run == str_to_lower(run)) &
+             (habitat_type == str_to_lower(habitat_type)) &
+             (wy_group == str_to_title(wy_group)))
+
+  varname <- case_when(
+    habitat_type == "spawning" ~ "durhsi_spawning",
+    str_to_title(gradient) == "Valley Lowland" ~ "durhsi_rearing_vl",
+    TRUE ~ "durhsi_rearing_vf")
+
+  drc_selected <-
+    drc_filtered$data[[1]] |>
+    select(flow_cfs = model_q,
+           durhsi = !!sym(varname))
+
+  return(drc_selected)
+
+}
+
+#' Create Duration Suitability Rating Curve for a streamgage (scaled to prediction point by drainage area and precipitation)
+#'
+#' @param streamgage Three-letter CDEC identifier for the streamgage
+#' @param reach Integer `comid` identifier for reach identifying the prediction point (used for scaling)
+#' @param scale Either "durhsi" to keep original flow scale and adjust duration HSI values (default), or "flow" to keep original duration HSI scale and adjust flow values.
+#' @param habitat_type Either "rearing" (default) or "spawning"
+#' @param run One of "fall" (default), "late fall", "winter", "spring", or "steelhead"
+#' @param wy_group Either "Dry" or "Wet" for water year type scenario
+#' @param gradient For rearing, either "Valley Foothill" (default) or "Valley Lowland"
+#'
+#' @returns A `tibble` with columns for flow (`flow_cfs`) and duration habitat suitability index (`durhsi`)
+#' @md
+#' @export
+#'
+#' @examples
+#'
+#' habitat_drc_weighted("FSB", habitat_type="rearing", gradient = "Valley Foothill", reach = 7978069)
+#'
+habitat_drc_weighted <- function(streamgage,
+                                 reach,
+                                 scale = "durhsi",
+                                 habitat_type = "rearing",
+                                 run = "fall",
+                                 wy_group = "Dry",
+                                 gradient = "Valley Foothill") {
+
+  gage_attr <-
+    habistat::streamgage_da_attr |>
+    filter(station_id == str_to_lower(streamgage)) |>
+    as.list()
+
+  comid_attr <-
+    habistat::flowline_attr |>
+    filter(comid == reach) |>
+    select(comid, da_area_sq_km, da_ppt_mean_mm) |>
+    as.list()
+
+  multiplier <-
+    (comid_attr$da_area_sq_km / gage_attr$da_gage) *
+    (comid_attr$da_ppt_mean_mm / gage_attr$pc_gage)
+
+  drc_unweighted <-
+    habistat::habitat_drc(streamgage = streamgage,
+                habitat_type = habitat_type,
+                run = run,
+                wy_group = wy_group,
+                gradient = gradient)
+
+  result <-
+    switch(scale,
+           "durhsi" =
+             tibble(flow_cfs = drc_unweighted$flow_cfs,
+                    durhsi = approx(x = drc_unweighted$flow_cfs * multiplier,
+                                    xout = drc_unweighted$flow_cfs,
+                                    y = drc_unweighted$durhsi,
+                                    method = "linear",
+                                    rule = 2:2,
+                                    na.rm = FALSE)$y),
+           "flow" =
+             drc_unweighted |>
+             mutate(flow_cfs = flow_cfs * multiplier))
+  return(result)
+
+}
+
+
+#' Create Flow-To-Suitable-Area Curve (with Duration HSI applied) for Reach
+#'
+#' @param reach Integer `comid` identifier for reach
+#' @param streamgage Three-letter CDEC identifier for the streamgage
+#' @param habitat_type Either "rearing" or "spawning"
+#' @param units Desired units for output, either "ft" for square ft per linear ft, or "ac" for total acres
+#' @param run One of "fall" (default), "late fall", "winter", "spring", or "steelhead"
+#' @param wy_group Either "Dry" or "Wet" for water year type scenario
+#' @param gradient For rearing, either "Valley Foothill" (default) or "Valley Lowland"
+#'
+#' @returns A `tibble` with columns for flow (`flow_cfs`) and suitable habitat (`habitat`)
+#' @md
+#' @export
+#'
+#' @examples
+#'
+#' habitat_fsa_duration_reach(reach = 7978069, streamgage = "FSB")
+#'
+habitat_fsa_duration_reach <- function(reach,
+                                       streamgage,
+                                       habitat_type = "rearing",
+                                       units = "ft",
+                                       run = "fall",
+                                       wy_group = "Dry",
+                                       gradient = "Valley Foothill") {
+
+  fsa <-
+    habistat::habitat_fsa(reach = reach,
+                          habitat_type = habitat_type,
+                          units = units)
+
+  drc <-
+    habistat::habitat_drc_weighted(streamgage = streamgage,
+                                   reach = reach,
+                                   habitat_type = habitat_type,
+                                   run = run,
+                                   wy_group = wy_group,
+                                   gradient = gradient)
+
+  fsa_weighted <-
+    habistat::duration_apply_dhsi_to_fsa_curve(fsa = fsa,
+                                               drc = drc,
+                                               # var names
+                                               fsa_q = flow_cfs,
+                                               fsa_wua = habitat,
+                                               drc_q = flow_cfs,
+                                               drc_dhsi = durhsi)
+
+  return(tibble(flow_cfs = fsa$flow_cfs,
+                habitat = approx(x = fsa_weighted$q,
+                                 xout = fsa$flow_cfs,
+                                 y = fsa_weighted$durwua,
+                                 rule = 2:2,
+                                 na.rm = F)$y))
+
+}
+
+
+#' Create Flow-To-Suitable-Area Curve (with Duration HSI applied) for Reach, Mainstem, or Watershed
+#'
+#' @param reach Integer `comid` identifier for reach (must provide either reach, mainstem, OR watershed)
+#' @param mainstem String name for mainstem (refer to `cv_mainstems` dataset for options)
+#' @param watershed String name for watershed (refer to `cv_watersheds` dataset for options)
+#' @param streamgage Three-letter CDEC identifier for the streamgage
+#' @param habitat_type Either "rearing" (default) or "spawning"
+#' @param units Desired units for output, either "ft" for square ft per linear ft, or "ac" for total acres
+#' @param run One of "fall" (default), "late fall", "winter", "spring", or "steelhead"
+#' @param wy_group Either "Dry" or "Wet" for water year type scenario
+#' @param gradient For rearing, either "Valley Foothill" (default) or "Valley Lowland"
+#'
+#' @returns A `tibble` with columns for flow (`flow_cfs`) and suitable habitat (`habitat`)
+#' @md
+#' @export
+#'
+#' @examples
+#'
+#' habitat_fsa_duration(reach = 7978069, streamgage = "FSB")
+#'
+#' habitat_fsa_duration(mainstem = "Feather River", streamgage = "FSB")
+#'
+habitat_fsa_duration <- function(reach,
+                                 mainstem,
+                                 watershed,
+                                 streamgage,
+                                 habitat_type = "rearing",
+                                 units = "ft",
+                                 run = "fall",
+                                 wy_group = "Dry",
+                                 gradient = "Valley Foothill") {
+
+  mode_geom <-
+    if (!missing(reach)) "reach" else
+      if (!missing(mainstem)) "mainstem" else
+        if (!missing(watershed)) "watershed"
+
+  if (mode_geom == "reach") {
+
+    habitat_fsa_duration_reach(reach = reach,
+                               streamgage = streamgage,
+                               habitat_type = habitat_type,
+                               units = units,
+                               run = run,
+                               wy_group = wy_group,
+                               gradient = gradient)
+
+  } else if (mode_geom %in% c("mainstem", "watershed")) {
+
+    group_var <-
+      switch(mode_geom,
+             "mainstem" = "river_cvpia",
+             "watershed" = "watershed_level_3")
+
+    flow_xw <-
+      switch(mode_geom,
+             "mainstem" = habistat::cv_mainstems_flow_xw,
+             "watershed" = habistat::cv_watersheds_flow_xw)
+
+    comids <-
+      switch(mode_geom,
+             "mainstem" =
+               habistat::cv_mainstems |>
+               filter(river_cvpia == mainstem) |>
+               pull(comid),
+             "watershed" =
+               habistat::cv_watersheds |>
+               filter(river_cvpia == mainstem) |>
+               pull(comid))
+
+    scaled_predictions <-
+      flow_xw |>
+      filter(comid %in% comids) |>
+      mutate(fsa = map2(comid, multiplier, function(x, y) {
+        habistat::habitat_fsa_reach_scaled(reach = x,
+                                           multiplier = y,
+                                           habitat_type = habitat_type,
+                                           units = "ft")})) |> # output in units ft2/ft
+      mutate(drc = map2(comid, streamgage, function(x, y) {
+        habistat::habitat_drc_weighted(reach = x,
+                                       streamgage = y,
+                                       run = run,
+                                       wy_group = wy_group,
+                                       gradient = gradient,
+                                       scale = "flow")})) |>
+      mutate(fsa_x_drc = map2(fsa, drc, function(f, d) {
+        fsa_weighted <-
+          habistat::duration_apply_dhsi_to_fsa_curve(fsa = f,
+                                                     drc = d,
+                                                     # var names
+                                                     fsa_q = flow_cfs,
+                                                     fsa_wua = habitat,
+                                                     drc_q = flow_cfs,
+                                                     drc_dhsi = durhsi)
+        return(tibble(flow_cfs = f$flow_cfs,
+                      habitat = approx(x = fsa_weighted$q,
+                                       xout = f$flow_cfs,
+                                       y = fsa_weighted$durwua,
+                                       rule = 2:2,
+                                       na.rm = F)$y))
+      })) |>
+      inner_join(habistat::flowline_attr |>
+                   select(comid, reach_length_ft),
+                 by = join_by(comid)) |>
+      select(-fsa, -drc) |>
+      unnest(fsa_x_drc) |>
+      mutate(habitat_ft2 = habitat * reach_length_ft)
+
+    switch(mode_unit,
+           "ft" =
+             scaled_predictions |>
+             group_by(flow_cfs) |>
+             summarize(habitat = sum(habitat_ft2, na.rm = T) / sum(reach_length_ft),
+                       .groups = "drop"),
+           "ac" =
+             scaled_predictions |>
+             group_by(flow_cfs) |>
+             summarize(habitat = sum(habitat_ft2, na.rm = T) / 43560,
+                       .groups = "drop"))
+
+  }
+
+}
+
+#' Predict Habitat Area using a Flow-to-Suitable-Area Curve
+#'
+#' @param x A vector of flows at which to predict suitable habitat values
+#' @param reach Integer `comid` identifier for reach (must provide either reach, mainstem, OR watershed)
+#' @param mainstem String name for mainstem (refer to `cv_mainstems` dataset for options)
+#' @param watershed String name for watershed (refer to `cv_watersheds` dataset for options)
+#' @param streamgage (optional) Three-letter CDEC identifier for a streamgage
+#' @param habitat_type Either "rearing" (default) or "spawning"
+#' @param units Desired units for output, either "ft" for square ft per linear ft, or "ac" for total acres
+#' @param run (required if streamgage is provided) One of "fall" (default), "late fall", "winter", "spring", or "steelhead"
+#' @param wy_group (required if streamgage is provided) Either "Dry" or "Wet" for water year type scenario
+#' @param gradient (required if streamgage is provided) For rearing, either "Valley Foothill" (default) or "Valley Lowland"
+#' @param fsa_x (optional) Vector of flows for manually defined flow-to-suitable-area curve. If provided, overrides reach, mainstem, or watershed lookup.
+#' @param fsa_y (optional) Vector of habitat values for manually defined flow-to-suitable-area curve, of same length as `fsa_x`
+#'
+#' @returns A vector of the same length as `x` containing predicted suitable habitat values
+#' @md
+#' @export
+#'
+#' @examples
+#'
+#' # example non-temporal prediction given comid
+#' habitat_predict(c(0, 10, 150, 300, 9999), reach = 7978069)
+#'
+#' # example temporal prediction given comid and streamgage
+#' habitat_predict(c(0, 10, 150, 300, 9999), reach = 7978069, streamgage = "FSB")
+#'
+#' # example non-temporal prediction given mainstem
+#' habitat_predict(c(0, 10, 150, 300, 9999), mainstem = "Feather River")
+#'
+#' # example temporal prediction given comid and streamgage
+#' habitat_predict(c(0, 10, 150, 300, 9999), mainstem = "Feather River", streamgage = "FSB")
+#'
+#' # example manual prediction given custom provided flow-to-suitable-area curve
+#' habitat_predict(c(0, 10, 150, 300, 9999), fsa_x = c(0, 100, 1000), fsa_y = c(47, 470, 4700))
+#'
+habitat_predict <- function(x,
+                            reach, mainstem, watershed,
+                            streamgage,
+                            fsa_x,
+                            fsa_y,
+                            habitat_type = "rearing",
+                            units = "ft",
+                            run = "fall",
+                            wy_group = "Dry",
+                            gradient = "Valley Foothill") {
+
+  mode_geom <-
+    if (!missing(reach)) "reach" else
+      if (!missing(mainstem)) "mainstem" else
+        if (!missing(watershed)) "watershed"
+
+  mode_unit <-
+    if (units %in% c("ft", "feet", "ft2/lf")) "ft" else
+      if(units %in% c("ac", "acres")) "ac"
+
+  if (isTRUE((!missing(fsa_x) && (!missing(fsa_y))))) {
+
+    fsa <- tibble(flow_cfs = fsa_x,
+                  habitat = fsa_y)
+
+  } else if (!missing(streamgage)) {
+
+    fsa <- habistat::habitat_fsa_duration(reach = reach,
+                                          mainstem = mainstem,
+                                          watershed = watershed,
+                                          streamgage = streamgage,
+                                          habitat_type = habitat_type,
+                                          units = units,
+                                          run = run,
+                                          wy_group = wy_group,
+                                          gradient = gradient)
+
+  } else {
+
+    fsa <- habistat::habitat_fsa(reach = reach,
+                                 mainstem = mainstem,
+                                 watershed = watershed,
+                                 habitat_type = habitat_type,
+                                 units = units)
+
+  }
+
+  result <- approx(x = if_else(fsa$flow_cfs > 0, log10(fsa$flow_cfs), 0),
+                   y = fsa$habitat,
+                   xout = if_else(x > 0, log10(x), 0),
+                   method = "linear",
+                   rule = 2:2)
+
+  return(result$y)
+
+}
diff --git a/man/habitat_drc.Rd b/man/habitat_drc.Rd
new file mode 100644
index 0000000..0275046
--- /dev/null
+++ b/man/habitat_drc.Rd
@@ -0,0 +1,36 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/habitat.R
+\name{habitat_drc}
+\alias{habitat_drc}
+\title{Create Duration Suitability Rating Curve for a streamgage}
+\usage{
+habitat_drc(
+  streamgage,
+  habitat_type = "rearing",
+  run = "fall",
+  wy_group = "Dry",
+  gradient = "Valley Foothill"
+)
+}
+\arguments{
+\item{streamgage}{Three-letter CDEC identifier for the streamgage}
+
+\item{habitat_type}{Either "rearing" (default) or "spawning"}
+
+\item{run}{One of "fall" (default), "late fall", "winter", "spring", or "steelhead"}
+
+\item{wy_group}{Either "Dry" or "Wet" for water year type scenario}
+
+\item{gradient}{For rearing, either "Valley Foothill" (default) or "Valley Lowland"}
+}
+\value{
+A \code{tibble} with columns for flow (\code{flow_cfs}) and duration habitat suitability index (\code{durhsi})
+}
+\description{
+Create Duration Suitability Rating Curve for a streamgage
+}
+\examples{
+
+habitat_drc("FSB", habitat_type="rearing", gradient = "Valley Foothill")
+
+}
diff --git a/man/habitat_drc_weighted.Rd b/man/habitat_drc_weighted.Rd
new file mode 100644
index 0000000..a892dcd
--- /dev/null
+++ b/man/habitat_drc_weighted.Rd
@@ -0,0 +1,42 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/habitat.R
+\name{habitat_drc_weighted}
+\alias{habitat_drc_weighted}
+\title{Create Duration Suitability Rating Curve for a streamgage (scaled to prediction point by drainage area and precipitation)}
+\usage{
+habitat_drc_weighted(
+  streamgage,
+  reach,
+  scale = "durhsi",
+  habitat_type = "rearing",
+  run = "fall",
+  wy_group = "Dry",
+  gradient = "Valley Foothill"
+)
+}
+\arguments{
+\item{streamgage}{Three-letter CDEC identifier for the streamgage}
+
+\item{reach}{Integer \code{comid} identifier for reach identifying the prediction point (used for scaling)}
+
+\item{scale}{Either "durhsi" to keep original flow scale and adjust duration HSI values (default), or "flow" to keep original duration HSI scale and adjust flow values.}
+
+\item{habitat_type}{Either "rearing" (default) or "spawning"}
+
+\item{run}{One of "fall" (default), "late fall", "winter", "spring", or "steelhead"}
+
+\item{wy_group}{Either "Dry" or "Wet" for water year type scenario}
+
+\item{gradient}{For rearing, either "Valley Foothill" (default) or "Valley Lowland"}
+}
+\value{
+A \code{tibble} with columns for flow (\code{flow_cfs}) and duration habitat suitability index (\code{durhsi})
+}
+\description{
+Create Duration Suitability Rating Curve for a streamgage (scaled to prediction point by drainage area and precipitation)
+}
+\examples{
+
+habitat_drc_weighted("FSB", habitat_type="rearing", gradient = "Valley Foothill", reach = 7978069)
+
+}
diff --git a/man/habitat_fsa.Rd b/man/habitat_fsa.Rd
new file mode 100644
index 0000000..ef30159
--- /dev/null
+++ b/man/habitat_fsa.Rd
@@ -0,0 +1,32 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/habitat.R
+\name{habitat_fsa}
+\alias{habitat_fsa}
+\title{Create Flow-To-Suitable-Area Curve for Reach, Mainstem, or Watershed}
+\usage{
+habitat_fsa(reach, mainstem, watershed, habitat_type = "rearing", units = "ft")
+}
+\arguments{
+\item{reach}{Integer \code{comid} identifier for reach (must provide either reach, mainstem, OR watershed)}
+
+\item{mainstem}{String name for mainstem (refer to \code{cv_mainstems} dataset for options)}
+
+\item{watershed}{String name for watershed (refer to \code{cv_watersheds} dataset for options)}
+
+\item{habitat_type}{Either "rearing" (default) or "spawning"}
+
+\item{units}{Either "ft" for square ft per linear ft, or "ac" for total acres}
+}
+\value{
+A \code{tibble} with columns for flow (\code{flow_cfs}) and suitable habitat (\code{habitat})
+}
+\description{
+Create Flow-To-Suitable-Area Curve for Reach, Mainstem, or Watershed
+}
+\examples{
+
+habitat_fsa(reach = 7978069, units = "ft")
+
+habitat_fsa(mainstem = "Feather River", units = "ac")
+
+}
diff --git a/man/habitat_fsa_duration.Rd b/man/habitat_fsa_duration.Rd
new file mode 100644
index 0000000..1d8ca3a
--- /dev/null
+++ b/man/habitat_fsa_duration.Rd
@@ -0,0 +1,49 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/habitat.R
+\name{habitat_fsa_duration}
+\alias{habitat_fsa_duration}
+\title{Create Flow-To-Suitable-Area Curve (with Duration HSI applied) for Reach, Mainstem, or Watershed}
+\usage{
+habitat_fsa_duration(
+  reach,
+  mainstem,
+  watershed,
+  streamgage,
+  habitat_type = "rearing",
+  units = "ft",
+  run = "fall",
+  wy_group = "Dry",
+  gradient = "Valley Foothill"
+)
+}
+\arguments{
+\item{reach}{Integer \code{comid} identifier for reach (must provide either reach, mainstem, OR watershed)}
+
+\item{mainstem}{String name for mainstem (refer to \code{cv_mainstems} dataset for options)}
+
+\item{watershed}{String name for watershed (refer to \code{cv_watersheds} dataset for options)}
+
+\item{streamgage}{Three-letter CDEC identifier for the streamgage}
+
+\item{habitat_type}{Either "rearing" (default) or "spawning"}
+
+\item{units}{Desired units for output, either "ft" for square ft per linear ft, or "ac" for total acres}
+
+\item{run}{One of "fall" (default), "late fall", "winter", "spring", or "steelhead"}
+
+\item{wy_group}{Either "Dry" or "Wet" for water year type scenario}
+
+\item{gradient}{For rearing, either "Valley Foothill" (default) or "Valley Lowland"}
+}
+\value{
+A \code{tibble} with columns for flow (\code{flow_cfs}) and suitable habitat (\code{habitat})
+}
+\description{
+Create Flow-To-Suitable-Area Curve (with Duration HSI applied) for Reach, Mainstem, or Watershed
+}
+\examples{
+habitat_fsa_duration(reach = 7978069, streamgage = "FSB")
+
+habitat_fsa_duration(mainstem = "Feather River", streamgage = "FSB")
+
+}
diff --git a/man/habitat_fsa_duration_reach.Rd b/man/habitat_fsa_duration_reach.Rd
new file mode 100644
index 0000000..143ce5a
--- /dev/null
+++ b/man/habitat_fsa_duration_reach.Rd
@@ -0,0 +1,42 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/habitat.R
+\name{habitat_fsa_duration_reach}
+\alias{habitat_fsa_duration_reach}
+\title{Create Flow-To-Suitable-Area Curve (with Duration HSI applied) for Reach}
+\usage{
+habitat_fsa_duration_reach(
+  reach,
+  streamgage,
+  habitat_type = "rearing",
+  units = "ft",
+  run = "fall",
+  wy_group = "Dry",
+  gradient = "Valley Foothill"
+)
+}
+\arguments{
+\item{reach}{Integer \code{comid} identifier for reach}
+
+\item{streamgage}{Three-letter CDEC identifier for the streamgage}
+
+\item{habitat_type}{Either "rearing" or "spawning"}
+
+\item{units}{Desired units for output, either "ft" for square ft per linear ft, or "ac" for total acres}
+
+\item{run}{One of "fall" (default), "late fall", "winter", "spring", or "steelhead"}
+
+\item{wy_group}{Either "Dry" or "Wet" for water year type scenario}
+
+\item{gradient}{For rearing, either "Valley Foothill" (default) or "Valley Lowland"}
+}
+\value{
+A \code{tibble} with columns for flow (\code{flow_cfs}) and suitable habitat (\code{habitat})
+}
+\description{
+Create Flow-To-Suitable-Area Curve (with Duration HSI applied) for Reach
+}
+\examples{
+
+habitat_fsa_duration_reach(reach = 7978069, streamgage = "FSB")
+
+}
diff --git a/man/habitat_fsa_reach.Rd b/man/habitat_fsa_reach.Rd
new file mode 100644
index 0000000..44fb91a
--- /dev/null
+++ b/man/habitat_fsa_reach.Rd
@@ -0,0 +1,26 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/habitat.R
+\name{habitat_fsa_reach}
+\alias{habitat_fsa_reach}
+\title{Create Flow-To-Suitable-Area-Curve for Individual Reach (unscaled)}
+\usage{
+habitat_fsa_reach(reach, habitat_type = "rearing", units = "ft")
+}
+\arguments{
+\item{reach}{Integer \code{comid} identifier for reach}
+
+\item{habitat_type}{Either "rearing" or "spawning"}
+
+\item{units}{Desired units for output, either "ft" for square ft per linear ft, or "ac" for total acres}
+}
+\value{
+A \code{tibble} with columns for flow (\code{flow_cfs}) and suitable habitat (\code{habitat})
+}
+\description{
+Create Flow-To-Suitable-Area-Curve for Individual Reach (unscaled)
+}
+\examples{
+
+habitat_fsa_reach(reach = 7978069)
+
+}
diff --git a/man/habitat_fsa_reach_scaled.Rd b/man/habitat_fsa_reach_scaled.Rd
new file mode 100644
index 0000000..ffdd08b
--- /dev/null
+++ b/man/habitat_fsa_reach_scaled.Rd
@@ -0,0 +1,33 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/habitat.R
+\name{habitat_fsa_reach_scaled}
+\alias{habitat_fsa_reach_scaled}
+\title{Create Flow-To-Suitable-Area Curve for Individual Reach (scaled by multiplier)}
+\usage{
+habitat_fsa_reach_scaled(
+  reach,
+  multiplier,
+  habitat_type = "rearing",
+  units = "ft"
+)
+}
+\arguments{
+\item{reach}{Integer \code{comid} identifier for reach}
+
+\item{multiplier}{Numeric multiplier to scale flow}
+
+\item{habitat_type}{Either "rearing" (default) or "spawning"}
+
+\item{units}{Desired units for output, either "ft" for square ft per linear ft, or "ac" for total acres}
+}
+\value{
+A \code{tibble} with columns for flow (\code{flow_cfs}) and suitable habitat (\code{habitat})
+}
+\description{
+Create Flow-To-Suitable-Area Curve for Individual Reach (scaled by multiplier)
+}
+\examples{
+
+habitat_fsa_reach_scaled(reach = 7978069)
+
+}
diff --git a/man/habitat_predict.Rd b/man/habitat_predict.Rd
new file mode 100644
index 0000000..87c8ef2
--- /dev/null
+++ b/man/habitat_predict.Rd
@@ -0,0 +1,69 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/habitat.R
+\name{habitat_predict}
+\alias{habitat_predict}
+\title{Predict Habitat Area using a Flow-to-Suitable-Area Curve}
+\usage{
+habitat_predict(
+  x,
+  reach,
+  mainstem,
+  watershed,
+  streamgage,
+  fsa_x,
+  fsa_y,
+  habitat_type = "rearing",
+  units = "ft",
+  run = "fall",
+  wy_group = "Dry",
+  gradient = "Valley Foothill"
+)
+}
+\arguments{
+\item{x}{A vector of flows at which to predict suitable habitat values}
+
+\item{reach}{Integer \code{comid} identifier for reach (must provide either reach, mainstem, OR watershed)}
+
+\item{mainstem}{String name for mainstem (refer to \code{cv_mainstems} dataset for options)}
+
+\item{watershed}{String name for watershed (refer to \code{cv_watersheds} dataset for options)}
+
+\item{streamgage}{(optional) Three-letter CDEC identifier for a streamgage}
+
+\item{fsa_x}{(optional) Vector of flows for manually defined flow-to-suitable-area curve. If provided, overrides reach, mainstem, or watershed lookup.}
+
+\item{fsa_y}{(optional) Vector of habitat values for manually defined flow-to-suitable-area curve, of same length as \code{fsa_x}}
+
+\item{habitat_type}{Either "rearing" (default) or "spawning"}
+
+\item{units}{Desired units for output, either "ft" for square ft per linear ft, or "ac" for total acres}
+
+\item{run}{(required if streamgage is provided) One of "fall" (default), "late fall", "winter", "spring", or "steelhead"}
+
+\item{wy_group}{(required if streamgage is provided) Either "Dry" or "Wet" for water year type scenario}
+
+\item{gradient}{(required if streamgage is provided) For rearing, either "Valley Foothill" (default) or "Valley Lowland"}
+}
+\value{
+A vector of the same length as \code{x} containing predicted suitable habitat values
+}
+\description{
+Predict Habitat Area using a Flow-to-Suitable-Area Curve
+}
+\examples{
+# example non-temporal prediction given comid
+habitat_predict(c(0, 10, 150, 300, 9999), reach = 7978069)
+
+# example temporal prediction given comid and streamgage
+habitat_predict(c(0, 10, 150, 300, 9999), reach = 7978069, streamgage = "FSB")
+
+# example non-temporal prediction given mainstem
+habitat_predict(c(0, 10, 150, 300, 9999), mainstem = "Feather River")
+
+# example temporal prediction given comid and streamgage
+habitat_predict(c(0, 10, 150, 300, 9999), mainstem = "Feather River", streamgage = "FSB")
+
+# example manual prediction given custom provided flow-to-suitable-area curve
+habitat_predict(c(0, 10, 150, 300, 9999), fsa_x = c(0, 100, 1000), fsa_y = c(47, 470, 4700))
+
+}