docs: update release notes (#1636)

* add description of the bug fixed by PR #1633
* extend test_gwf_sfr_inactive autotest to reactivate sfr reaches after inactivating 3 of 6 reaches
* update test_gwf_sfr_inactive autotest test description

autotest/test_gwf_sfr_inactive.py

@@ -1,4 +1,28 @@
-# test based on issue 1585 fix
+"""
+This test inactivation of SFR reaches during a simulation.
+The test is based on the example provided with issue 1585,
+which resulted in a divide by zero error when reaches were
+inactivated in the second stress period.
+
+The test has 6 sfr reaches that are not connected to the 
+groundwater model.
+
+            Reaches
+   1 -o- 2 -o- 3 -o- 4 -o- 5 -o- 6
+
+Test parameters:
+  
+  1. initially all reaches are active
+  2. in the 2nd stress period reaches 4, 5, and 6 are 
+     inactivated
+  3. in the 3rd stress period reach 4 is reactivated
+  4. in the 4th stress period reach 5 is reactivated
+  5. in the 5th stress period reach 6 is reactivated
+  
+The test evaluates OUTFLOW and EXT-OUTFLOW for reaches
+3, 4, 5, and 6 against expected values.
+"""
+
 import flopy
 import numpy as np
 import pytest
@@ -12,7 +36,7 @@
 def build_models(idx, test):
     # static model data
     # temporal discretization
-    nper = 2
+    nper = 5
     tdis_rc = []
     for _ in range(nper):
         tdis_rc.append((1.0, 1, 1.0))
@@ -188,16 +212,22 @@ def build_models(idx, test):
             [4, "status", "inactive"],
             [5, "status", "inactive"],
         ],
+        2: [
+            [3, "status", "active"],
+        ],
+        3: [
+            [4, "status", "active"],
+        ],
+        4: [
+            [5, "status", "active"],
+        ],
     }
 
-    sfr_dict = {
-        f"{paktest}_obs.csv": [
-            ("r3_out", "outflow", (2,)),
-            ("r3_ext", "ext-outflow", (2,)),
-            ("r6_out", "outflow", (5,)),
-            ("r6_ext", "ext-outflow", (5,)),
-        ]
-    }
+    sfr_obs = []
+    for i in range(2, 6):
+        sfr_obs.append((f"r{i + 1}_out", "outflow", (i,)))
+        sfr_obs.append((f"r{i + 1}_ext", "ext-outflow", (i,)))
+    sfr_dict = {f"{paktest}_obs.csv": sfr_obs}
     sfr = flopy.mf6.ModflowGwfsfr(
         gwf,
         print_stage=True,
@@ -224,10 +254,14 @@ def check_output(idx, test):
     print("Checking sfr outflow and external outflow")
     obs_values = flopy.utils.Mf6Obs(test.workspace / f"{paktest}_obs.csv")
     test_values = {
-        "R3_OUT": [-1.0, 0.0],
-        "R3_EXT": [0.0, -1.0],
-        "R6_OUT": [0.0, 0.0],
-        "R6_EXT": [-1.0, 0.0],
+        "R3_OUT": [-1.0, 0.0, -1.0, -1.0, -1.0],
+        "R3_EXT": [0.0, -1.0, 0.0, 0.0, 0.0],
+        "R6_OUT": [0.0, 0.0, 0.0, 0.0, 0.0],
+        "R6_EXT": [-1.0, 0.0, 0.0, 0.0, -1.0],
+        "R4_OUT": [-1.0, 0.0, 0.0, -1.0, -1.0],
+        "R4_EXT": [0.0, 0.0, -1.0, 0.0, 0.0],
+        "R5_OUT": [-1.0, 0.0, 0.0, 0.0, -1.0],
+        "R5_EXT": [0.0, 0.0, 0.0, -1.0, 0.0],
     }
     for key, value in test_values.items():
         assert np.array_equal(

doc/ReleaseNotes/develop.tex

@@ -17,7 +17,7 @@
 	%	\item xxx
 	%\end{itemize}
 
-	%\textbf{\underline{BUG FIXES AND OTHER CHANGES TO EXISTING FUNCTIONALITY}} \\
+	\textbf{\underline{BUG FIXES AND OTHER CHANGES TO EXISTING FUNCTIONALITY}} \\
 	%\underline{BASIC FUNCTIONALITY}
 	%\begin{itemize}
 	%	\item xxx
@@ -39,12 +39,12 @@
 	%	\item xxx
 	%\end{itemize}
 
-	%\underline{ADVANCED STRESS PACKAGES}
-	%\begin{itemize}
-	%	\item 
+	\underline{ADVANCED STRESS PACKAGES}
+	\begin{itemize}
+		\item A divide by zero error would occur in the Streamflow Routing package when reaches were deactivated during a simulation. This bug was fixed by checking if the downstream reach is inactive before calculating the flow to the downstream reach.
 	%	\item xxx
 	%	\item xxx
-	%\end{itemize}
+	\end{itemize}
 
 	%\underline{SOLUTION}
 	%\begin{itemize}